"Is Climate 'Lukewarmism' Legitimate?"

Guest post by David Middleton

A very thoughtful column by Ross Pomeroy at Real Clear Science…

Is Climate ‘Lukewarmism’ Legitimate?

To many, prominent writers Matt Ridley, Ross Douthat, and Oren Cass are a baffling bunch. They are the visible proponents of the position that climate change is real, manmade, and occurring as predicted by the Intergovernmental Panel on Climate Change (IPCC), yet it does not yet constitute a worrying or catastrophic problem. They are “lukewarmers.”

So what do we make of these climate change moderates, who do not hold the invalid, unevidenced opinions of those who deny the scientific consensus, yet at the same time, do not ascribe to the apocalyptic scenarios espoused by climate alarmists and the accompanying solutions to avert them?

As far as I can tell, lukewarmers’ views are legitimate. The mountains of evidence present in the most recent IPCC assessment report, comprising more than 9,200 peer-reviewed studies, cannot simply be cast aside as the product of a conspiracy or a statistical fluke of climate models. If lukewarmers accept the science, they are on solid ground.


To his credit, lukewarm New York Times columnist Ross Douthat agrees. “Every lukewarmer, including especially those in positions of political authority, should be pressed to identify trends that would push them toward greater alarmism and a sharper focus on the issue.”

In other words, they must recognize some level of evidence that will cause them to change their views. If they don’t, they have proven themselves not to be lukewarm moderates but dogmatic deniers.

Full Article on Real Clear Science

“Every lukewarmer, including especially those in positions of political authority, should be pressed to identify trends that would push them toward greater alarmism and a sharper focus on the issue.”

This is not a one-sided question. It should also be asked, “What trends would push a lukewarmer towards lesser alarmism and a sharper focus on the issue.”

For this lukewarmer, there is a level of evidence that would cause me to change my views.  This would be some level of evidence above…

Almost every catastrophic prediction is based on climate models using the RCP 8.5 scenario (RCP = relative concentration pathway) and a far-too high climate sensitivity. RCP 8.5 is not even suitable for bad science fiction. Actual emissions are tracking closer to RCP 6.0. When a realistic transient climate response is applied to RCP 6.0 emissions, the warming tracks RCP 4.5… A scenario which stays below the “2° C limit,” possibly even below 1.5° C.


Ensemble of RCP 4.5 models and observed temperatures ( Zeke Hausfather at Carbon Brief).

Note that the 2σ (95%) range in 2100 is 2° C (± 1° C)… And the model is running a little hot relative to the observations.  The 2016 El Niño should spike toward the top of the 2σ range, not toward the model mean.  I am working on a more detailed post on this and “Gavin’s Twitter Trick,” that I hope to post later this week – So I won’t be responding to comments about the hotness of the models in this thread.

Ross Douthat had an excellent column on this in the New York Times (of all places)…

Neither Hot Nor Cold on Climate

Ross Douthat JUNE 3, 2017

LIKE a lot of conservatives who write about public policy, my views on climate change place me in the ranks of what the British writer Matt Ridley once dubbed the “lukewarmers.”

Lukewarmers accept that the earth is warming and that our civilization’s ample CO2 emissions are a major cause. They doubt, however, that climate change represents a crisis unique among the varied challenges we face, or that the global regulatory schemes advanced to deal with it will work as advertised. And they raise an eyebrow at the contrast between the apocalyptic, absolutist rhetoric with which these schemes are regularly defended and their actual details, which seem mostly designed to enable the globe’s statesmen to greenwash the pursuit of economic and political self-interest.

More specifically, lukewarmers look at the Intergovernmental Panel on Climate Change’s official projections and see a strong likelihood that rising temperatures will drag on G.D.P. without leading to catastrophe. They look at the record of climatological predictions and see a pattern in which observed warming hugs the lower, non-disastrous end of the spectrum of projections. And they look at the substance of the Paris accord, which papered over a failed attempt to set binding emission rules with a set of fine-sounding promises, and see little to justify all the anguish and despair over Donald Trump’s decision to abandon it.


NY Times

Although, I do take issue with is this statement:

Lukewarmers accept that the earth is warming and that our civilization’s ample CO2 emissions are a major cause.

The Earth’s average surface temperature has warmed since the 1600’s and our CO2 emissions have played a role in that warming.  Relative to the total carbon flux, our emissions are hardly “ample” and 20-30% doesn’t strike me as a “major cause.”

And I would also take issue with Mr. Douthat’s answer to his own challenge:

I’ll answer that challenge myself: My own alarm over climate change has gone up modestly since the Obama-era cap-and-trade debates, as the decade or more in which observed warming was slow or even flat — the much-contested warming “pause” — has given way to a clearer rise in global temperatures.

If you chart this spike against the range of climate change projections, it brings the trend up into the middle of climatologists’ scenarios for the first time in some years. Maybe that will be temporary and it will fall back. But the closer the real trend gets to the worst-case projections, the more my lukewarmism will look Pollyannish and require substantial reassessment.

The 2016 El Niño spike didn’t bring “the *trend* up into the middle of climatologists’ scenarios.”  The bottom of the 2σ range is the P97.5 case, 97.5% of the model runs resulted in more warming than P97.5.  The model mean is the P50 case, 50% of the model runs resulted in more warming than P50.  The top of the 2σ range is the P02.5 case, 2.5% of the model runs resulted in more warming than P02.5. A major El Niño spike should spike from P50 toward P02.5, not from P97.5 toward P50.  For a discussion of this nomenclature see The Good, the Bad and the Null Hypothesis.

Lukewarmerism is well-grounded in science and economics.  I suppose it could even be viewed as a climatological version of Pascal’s wager.  Matt Ridley also has an excellent article on Lukewarmerism…


Published on: Tuesday, 20 January, 2015
The polarisation of the climate debate has gone too far

This article appeared in the Times on January 19, 2015:

I am a climate lukewarmer. That means I think recent global warming is real, mostly man-made and will continue but I no longer think it is likely to be dangerous and I think its slow and erratic progress so far is what we should expect in the future. That last year was the warmest yet, in some data sets, but only by a smidgen more than 2005, is precisely in line with such lukewarm thinking.

This view annoys some sceptics who think all climate change is natural or imaginary, but it is even more infuriating to most publicly funded scientists and politicians, who insist climate change is a big risk. My middle-of-the-road position is considered not just wrong, but disgraceful, shameful, verging on scandalous. I am subjected to torrents of online abuse for holding it, very little of it from sceptics.

I was even kept off the shortlist for a part-time, unpaid public-sector appointment in a field unrelated to climate because of having this view, or so the headhunter thought. In the climate debate, paying obeisance to climate scaremongering is about as mandatory for a public appointment, or public funding, as being a Protestant was in 18th-century England.



Marlo Lewis has provided a handy list of the range of opinions that come under the “lukewarmer” label. I subscribe to each of these in some form or to some degree:

“In general, I would describe a ‘lukewarmer’ as someone who:

– Thinks anthropogenic climate change is real but  very far from being a planetary emergency

– Takes due notice of the increasing divergence between climate model predictions and observations and the  growing body of scientific literature challenging IPCC climate sensitivity estimates.

– Regards the usual pastiche of remedies — carbon taxes, cap-and-trade, renewable energy quota, CO2 performance standards – as either an  expensive exercise in futility or a  ‘cure’ worse than the alleged disease (depending how aggressively those policies are implemented).

– Is impressed by — and thankful for — the immense albeit usually unsung benefits of the CO2 fertilization effect on  global agriculture and  green things generally.

– Recognizes that poverty remains the world’s leading cause of  preventable illness and premature death.

– Understands that plentiful, affordable, scalable energy (most of which comes from  CO2-emitting fossil fuels) is essential to poverty eradication and progress towards a  healthier, safer, more prosperous world.”


Update 2:

The main point of my article was to draw attention to how ad-hominem, vicious and personal the attacks on lukewarmers now are from the guardians of the flame of climate alarm. Though I had a huge and overwhelmingly positive response, I could not have wished for a better example of my point than some of the negative reactions to this article. An egregious example was the death threats I received from a Guardian contributor and Greenpeace “translator”, Gary Evans.

On 21 January The Guardian published an article by Dana Nuccitelli, specifically criticizing me. The article was illustrated with a picture of the severed head of a zombie. Beneath the article appeared the following comment from “Bluecloud”:

“Should that not be Ridley’s severed head in the photo?”


The Rational Optimist

Other Lukewarmers like Dr. Pat Michaels, Chip Knappenberger, Dr. Judith Curry, Dr. Roy Spencer and Dr. John Christy are routinely subjected to similar ad hominem attacks from the “guardians of the flame of climate alarm.”


So… If you are a fellow Lukewarmer… What evidence would push you toward alarmism?  What evidence would push you toward rejecting human impacts on the climate as being less than a rounding error? (Note: I view the impacts as only being slightly larger than a rounding error).

444 thoughts on “"Is Climate 'Lukewarmism' Legitimate?"

  1. There has been no doubt we have been in a warming trend over the past few decades. But before that we were in a cooling trend, and before that we were in a warming trend.
    Is there a pattern here?

      • At this time usefully accurate forecasts of the coming cooling to about 2650, with about 70 – 75 % probability of success ( according to my own expert opinion) can be made simply by convolving the 1000+/- and 60 year cycles. The establishment scientists and modelers , lukewarmers and the GWPF seem unable to grasp the common sense notion that the earth existed before about 1850 and that unless one knows where the earth is in relation to the longer term cycles – forecasting is futile.
        See Figs 1 – 12 at
        Here is the Abstract.
        The coming cooling: usefully accurate climate forecasting for policy makers.
        Dr. Norman J. Page
        Email: norpag@att.net
        DOI: 10.1177/0958305X16686488
        Energy & Environment
        0(0) 1–18
        (C )The Author(s) 2017
        Reprints and permissions:
        DOI: 10.1177/0958305X16686488
        This paper argues that the methods used by the establishment climate science community are not fit for purpose and that a new forecasting paradigm should be adopted. Earth’s climate is the result of resonances and beats between various quasi-cyclic processes of varying wavelengths. It is not possible to forecast the future unless we have a good understanding of where the earth is in time in relation to the current phases of those different interacting natural quasi periodicities. Evidence is presented specifying the timing and amplitude of the natural 60+/- year and, more importantly, 1,000 year periodicities (observed emergent behaviors) that are so obvious in the temperature record. Data related to the solar climate driver is discussed and the solar cycle 22 low in the neutron count (high solar activity) in 1991 is identified as a solar activity millennial peak and correlated with the millennial peak -inversion point – in the UAH temperature trend in about 2003. The cyclic trends are projected forward and predict a probable general temperature decline in the coming decades and centuries. Estimates of the timing and amplitude of the coming cooling are made. If the real climate outcomes follow a trend which approaches the near term forecasts of this working hypothesis, the divergence between the IPCC forecasts and those projected by this paper will be so large by 2021 as to make the current, supposedly actionable, level of confidence in the IPCC forecasts untenable
        Here is Fig 12
        Fig. 12 compares the IPCC forecast with the Akasofu (31) forecast (red harmonic) and with the simple and most reasonable working hypothesis of this paper (green line) that the “Golden Spike” temperature peak at about 2003 is the most recent peak in the millennial cycle. Akasofu forecasts a further temperature increase to 2100 to be 0.5°C ± 0.2C, rather than 4.0 C +/- 2.0C predicted by the IPCC. but this interpretation ignores the Millennial inflexion point at 2004. Fig. 12 shows that the well documented 60-year temperature cycle coincidentally also peaks at about 2003.Looking at the shorter 60+/- year wavelength modulation of the millennial trend, the most straightforward hypothesis is that the cooling trends from 2003 forward will simply be a mirror image of the recent rising trends. This is illustrated by the green curve in Fig. 12, which shows cooling until 2038, slight warming to 2073 and then cooling to the end of the century, by which time almost all of the 20th century warming will have been reversed.

      • I am one of those who accept that the globe has warmed since the LIA, but who has not seen convincing evidence that the globe today is any warmer than it was in the late 1930s/early 1940s, still less that CO2 has had any impact on the warming that has occurred. Indeed, I consider that there are multiple lines of evidence that suggest that the Northern Hemisphere is no warmer today than it was in the late 1930s/early 1940s, notwithstanding that since 1940 some 95% of all manmade CO2 has been emitted.
        It is interesting to have a quick look at HADCRUT4 and the warming and the rate of change of warming,viz:
        Now according to the IPCC, manmade CO2 emissions only became a significant factor after WW2, and that prior to then, manmade CO2 did not drive temperature rises.
        And yet there is no statistical difference in the rate of warming of the warming episodes that took place prior to WW2 when CO2 was not a factor (ie., the 1860 to 1880 warming, and the 1910 to 1940 warming), and the warming episode (late 20th century warming) when CO2 is claimed to be a factor.
        Phil Jones (the head of CRU) specifically confirmed that in the BBC interview:

        QUESTION: Do you agree that according to the global temperature record used by the IPCC, the rates of global warming from 1860-1880, 1910-1940 and 1975-1998 were identical?
        ANSWER:I have also included the trend over the period 1975 to 2009, which has a very similar trend to the period 1975-1998.
        So, in answer to the question, the warming rates for all 4 periods are similar and not statistically significantly different from each other.

        So it would appear that CO2 emissions post WW2 have not increased the rate of warming.
        Further one will note from the plot which only goes up to 2009, that as at 2009, the temperature anomaly was about +0.5 degC (may be +0.52 degC) and that in 1880 it was 0.4degC, 1940 it was +0.4 degC, and in 1943 it was +0.4 degC.
        Thus as at around 2009, the temperature anomaly was only around +0.1 degC more than it was in the 1940s, or for that matter only about 0.1 degC above that of 1880. Given the error bounds of this reconstruction, we cannot say that as in 2009, the temperature was any warmer than that seen in 1940 or for that matter in 1880.
        Given that CO2 is said to be an issue and driver of temperature change only post WW2, it follows that if CO2 has done anything, it has only increased the temperature by about 0.1degC over and above that seen in the 1940/43. So it would appear that manmade CO2 emissions are not doing much of substance (even if one were to accept that HADCRUT 4 is reasonably accurate).
        Of course, I accept that if this plot were to be updated through to 2017, the positive anomaly would be a little higher than the +0.5degC noted in 2009, but that is the result of the recent strong El Nino of 2015/16 and the ENSO cycle has yet to complete with a La Nina.
        Presently, the balance of forecasts is for a La Nina late 2017/early 2018, and if that foercast turns out to be correct, there will be a lag of a few months before it has a significant impact on temperatures. It follows that if there is such a La Nina, we may well be seeing in say April/May 2018, HADCRUT 4 with a positive anomaly around the 0.5degC mark and only some 0.1degC over and above temperatures seen in 1880 and in 1940/43 notwithstanding all that CO2 emitted by man over the intervening years.
        It is also interesting to have a look at HADCRUT for the Arctic (70 to 90 degN). Viz:
        It will be seen that the Arctic today is not as warm as it was in the 1930s/1940s. In the 24 year period between 1922 to 1946 some 12 years (ie., 50% of the time), there was a positive anomaly of +4 degC (or more), whereas in the recent 24 years between 1992 and 2016, there are only 6 years (ie., 25% of the time) where the temperature anomaly is + 4degC (or more). Indeed, recently the positive anomalies have only scrapped to the +4 deg C level, whereas in the past they were generally higher being +5 degC, + 6degC and even + 7degC. No recent year has reached the + 7 degC anomaly seen in 1937/8
        The temperature anomaly series do not withstand rigorous scientific study since they never compare like with like and are a constantly moving and altering feast, with stations coming and going, biases caused by high latitude station drop outs, increasing use of urban stations and drop out of rural stations, increasing use of airport stations (which airports have in any event undergone significant change), change of equipment from low sensitive slow response LIG thermometers in large volume enclosures, to high sensitive rapid response platinum resistance thermometers in small enclosures etc. etc
        I suspect that if we were to carry out a point by point remeasurement of the best sited stations (CRN1) in the Northern Hemisphere retrofitted with the same type of LIG thermometers as used in the past, and use the same practice and procedure as used at each station in the past, so that on a point by point basis modern day collected RAW data could be compared directly with historic RAW data collected at that station in the 1930s/1940s with no adjustments whatsoever, we would see that there has been no warming over and above the temperatures observed at the station in the 1930s/1940s. This would tell us a lot since this comparison would cover the period when some 95% of all manmade CO2 emissions have taken place.
        Our problem is poor quality data. What we require is good high quality data, and we should only work with high quality data. If not any signal to CO2 will inevitably be lost in the noise.

      • The funny is only that this pattern here and elsewhere has already been explained several times and there are still fellow-readers who ask: is there a pattern here? Loss of memory in younger people also seems to be a sign of the times. Or is it over-stimulation via smartphone that you can not remember anything?

      • richard verney, not at all impressed by your hand drawn arrows claiming to be trends. At least download some data and fit some linear trends and show the results or don’t bother.

      • Greg
        The trends illustrated by Richard Verney, which were the subject of the Phil Jones quote included in his comment, have appeared on WUWT several times. If you can’t be bothered to do some research for yourself, that’s your problem. So if you are not impresses, too bad.

      • Richard
        “It is interesting to have a quick look at HADCRUT4 and the warming and the rate of change of warming,viz:”
        This graph seems to go around for ever; it first appeared about 2010. It is not HADCRUT 4. And despite claims we don’t know who made it – the attribution is just to Jo Nova’s web site. And it disguises the fact that the warming since 1975, which is really a continuation of the earlier warming, has continued for a lot longer, and to much greater heights than shown. And shows no sign of stopping.

      • “richard verney September 25, 2017 at 9:03 am

        The temperature anomaly series do not withstand rigorous scientific study since they never compare like with like and are a constantly moving and altering feast, with stations coming and going, biases caused by high latitude station drop outs, increasing use of urban stations and drop out of rural stations, increasing use of airport stations (which airports have in any event undergone significant change), change of equipment from low sensitive slow response LIG thermometers in large volume enclosures, to high sensitive rapid response platinum resistance thermometers in small enclosures etc. etc

        Our problem is poor quality data. What we require is good high quality data, and we should only work with high quality data. If not any signal to CO2 will inevitably be lost in the noise.”


      • There’s an old philosophical question.
        How would you prove that God didn’t create the universe 1 second ago, with everything in place and everyone having full memories of their lives up to that point already in place.

    • We’ve not been in a warming trend for decades. We were in a warm cycle from the PDO flip of 1977 to the El Nino of 1999, but global average temperature has been flat since then, or cooling, except for the El Nino of 2016.
      Before that, as you note, we were in a cool cycle from the 1940s to 1977, and before that in a warm cycle. We’re recovering from the Little Ice Age Cold Period, which followed the Medieval Warm Period, which followed the Dark Ages CP, which followed the Roman WP, which followed the Greek Dark Ages CP, which followed the Minoan WP, which followed a CP, which followed the Egyptian WP, which followed a CP, which followed the Holocene Climatic Optimum.
      Despite the many pages of the IPCC, there is no actual evidence of a detectable human influence on global climate. Locally, yes. Witness Las Vegas, for instance.

      • Climate Guru Hansen said in 1999, that the 1930’s was 0.5C hotter than the year ,1998, and 2016, which makes the 1930’s the hottest years since that time, up to and including today.
        That doesn’t show up in the surface temperature charts because they have all been manipulated to show 1998 as hotter than the 1930’s
        Any surface temperature chart that does not show the 1930’s to be as hot or hotter than subsequent years (including 2016, which tied 1998 for temperature) means you are looking at a bogus, bastardized surface temperature chart. The Bastardizers are trying to fool you, and they do a pretty good job as even skeptics use these bogus charts to try to make their point.
        If the 1930’s doesn’t show hotter than 1998 and 2016, then you are looking at garbage being passed off as science.

      • TA,
        Yup, and when the world ceased warming after the 1990s, as Hansen expected or hoped would not be the case, then no problem! Just cook the books.

      • Sixto

        We were in a warm cycle from the PDO flip of 1977 to the El Nino of 1999, but global average temperature has been flat since then, or cooling, except for the El Nino of 2016.

        All the global temperature data sets, both surface and satellite, show a warming trend between 2000 and 2015: http://www.ysbl.york.ac.uk/~cowtan/applets/trend/trend.html
        I can’t find any that show cooling. What’s your source for that claim please?

      • DWR54,
        that warming rate is well below the IPCC per decade warming rate prediction. This one is Satellite data,
        Only .125C per decade.

    • Power of suggestion. I haven’t noticed any difference where I have lived since the early 70s. Still get 9 months of rain and occasional snow. Still get 3 months of hot dry summers. Still grow the same seasonal crops. Still get 4 seasons. Haven’t noticed anything unusual. It’s uneventful if there is warming but no climate change where I am

  2. As a lukewarmer (I feel that the climate change is real and that CO2 plays a minor role in it (sensitivity of 0.3 to 0.5C))
    The evidence that would push me towards being more concerned would be a solid warming trend that can’t be attributed to any of the known climate cycles.
    The evidence that would cause me to abandon my belief that CO2 plays a minor role would be evidence that natural cycles are sufficient to explain all of the warming. (Unfortunately we would need several hundred years of quality data to pull that off.)

      • As stated above, the CO2 signal is too small to be discerned in the over all temperature record.
        Despite your efforts to believe otherwise, this is not evidence that it is not there.

      • MarkW,
        But because it can’t be discerned, your belief that it is there is simply an article of CACA faith, not a scientific conclusion. Fairies and elves can’t be discerned either, but Sir Arthur Conan Doyle believed in them. John Knight, who posts here, believes that earth, plants, day and night were created before the sun, because the Bible tells him so.
        OK, now I really am gone.
        No hasta luego, porque no estaria un luego. Entonces, vayan ustedes con Dios.

      • While I admit that my beliefs can’t be proven from the data, the fact remains that CO2 does convert photons to heat. Both in the lab and the real world.
        On the other hand your frequent claims that it can’t exist because the signal is less than the noise in the climate system is equally fatuous.

    • I would say I am pretty close to this view. I think most of the warming we have seen since the 60’s, when I was a kid, has been due to natural causes and probably related to whatever caused the LIA. That period saw a growth of glaciers and very well recorded low temperatures in the Northern Hemisphere at least. This warming has been very good for mankind and slow enough that wildlife has been quite able to adapt. A warmer climate also generally means a wetter climate which combines with higher CO2 to be very beneficial for crops and other plant life. Even the Sahara is greening!
      There is no disaster unfolding or imminent!
      At this point there is no evidence that CO2 has any substantial effect on planetary temperatures and I see politics and grossly substandard and even phony, contrived science written all over this cause.
      The biggest problem I have with climate science is actually the scientific aspects of it. As a long time science buff I am extremely disappointed in what I see as a major corruption of a scientific field by political opportunists like Al Gore and many others, who see in it a means to attack Capitalism.
      I see lots of problems with Capitalism myself, but these people seek to tear it down with no clue as to what to put in its place. God knows, Marxism and Socialism and every other ism that has been tried have been murderous failures.
      If Capitalism needs to be superseded it has to be a better idea, not recycled garbage disguised as Environmentalism. The Left has run up against a bankruptcy of ideas and clings to this phony crisis only as a path to power-the only thing they still exist for.
      What would change my mind?
      Honest data that indicates an acceleration of warming which cannot be explained by natural causes. Or, a better physical understanding of oceanic processes that relate to climate. Or, a recognition of the LIA and a coherent explanation of its cause and how that relates to present climate. Or, just some decent science! The work of Michael Mann is especially egregious in its deceptions, but most other work I see in the field is equally as flawed and politically directed, just not always so deliberate and aggressively false. The field is dominated by third rate people who are not just doing bad work but deliberately pedalling garbage science. The dissection and trashing of Mann’s “Hockey Stick” crap by McIntyre and Mickitrick should have been the death of Mann’s career. Instead the cabal of falsifiers was so endemic in the field that they managed to close around him and protect the rottenest apple in the whole rotten barrel. Very disappointing for science and very destructive to the entire world.
      When people like Degrasse Tyson come out in support of the mainstream, and then make it obvious they really have no knowledge of the field, they do a great disservice to science. One can only conclude that they would rather protect their media status than show respect for proper science.
      This entire fiasco just shows how easily people of weak moral fibre can be bought off.

    • The evidence that would push me towards
      we have long term paleo records of CO2 and temperature going back at least 600k years. they all show the same thing. When CO2 is high, temperatures drop. When CO2 is low, temperatures rise.
      this evidence show that if anything, GHG sensitivity to CO2 is NEGATIVE. It does not in any way support the notion that CO2 sensitivity is > 0.

  3. I am a lukewarmer, but now trending away from the alarmist side to the ho hum side. I cannot get excited about warming as small as 1.5C and possibly 0.7C. Ho hum…
    Nothing short of a persistent (log) rise in satellite and balloon temperatures to follow CO2 rise would impress me. The ground and ocean temperature sets are worthless imo. I have zero trust in adjusted and homoginized data.

  4. Once again, those involved in the argument over CO2 emissions all seem the think “no change” will occur without our errecting windmills, solar panels, etc, when, in fact, simple economics is forcing
    far more significant emission reductions than anything that the trillions spent so far have accomplished.
    These people seem to be just about the only people on the planet who haven’t noticed the obvious
    transition from gas to electric power going on in the transportation sector, a huge potential change in emissions as soon as the grid reduces same. How extensive is this transformation? Well, several automakers will no longer build gas-only vehicles after he next few years, some (BMW,
    Mercedes-Benz, Volvo) will build an eletric version of every car they sell, etc. I count well over 40 electric models coming to dealer showrooms over the next several years.
    Less well known are the revolutionary advances in nuclear power, mostly by the adbent of practical molten salt reactors, which cost a fraction of the money and time to build and operate compared to the typical LWR reactors, and which are as safe as anyone could possibly wish.

    • Building the electric vehicles and selling them are two different things. Thus far the only thing driving (excuse the pun) electric vehicles is the fairly overt threat of compulsion and the only things enabling their sales are substantial tax rebates and carbon credits. When the dismal resale value of these highly limited and pricey vehicles becomes more well known the sales aspect will become that much harder.

      • ‘When the dismal resale value of these highly limited and pricey vehicles becomes more well known…”
        Hmm. First I’ve heard of this. Got some data you can share with us? How bad is it?

    • When you say “will build an electric version of every car they sell” what that translates into is mostly hybrids, which is essentially trendy and irrelevant. They are still ICEs. I looked at a gas-only car today that gets over 40 mpg hwy. Hybrids get what – 50 mpg? That 10 extra mpg is not worth the extra cost of a hybrid that will incur the additional cost of replacing the engine every 100,000 miles, or so (if not sooner), because of battery replacement .

    • So where do we have one of these molten salt reactors supplying major league grid power on a 24/7/365 basis ??
      I’m not aware of any of them operating in California, let alone enough of them to influence our energy supply.

    • transition from gas to electric power
      the power grid cannot support anything more than a few percent electric vehicles. we will need to increase the power grid by close to a factor of 10 to allow all electric vehicles. this will take a huge scientific breakthrough or it will simply not happen due to costs.
      most people are not aware that the electricity used by a house is about 1 gallon of gasoline equivalent per day. even if we doubled energy production, you cannot move a car very far on 1 gallon of gasoline per day per household. now factor in truck traffic, and what is required to keep a modern economy moving.

  5. Climate 101.
    The accepted global temperature record is a complete fiction which even if it were true, may have limited relevance. CO2 is not the main driver of the greenhouse effect, water vapour is. There are enormous holes in the knowledge of the climate and models yet Ridley et al will argue about climate sensitivity to 2 decimal places.
    Lukewarmers like the GWPF are a fifth column that make real opposition look ridiculous. They do a LOT more harm than good. They look like a valid opposition but they aren’t, they’re enablers of loony alarmism who give them credibility they don’t deserve.
    Freeman Dyson thinks climate forecasts are absurd.

    • Lukewarmers generally became lukewarmers because…

      The accepted global temperature record is a complete fiction which even if it were true, may have limited relevance. CO2 is not the main driver of the greenhouse effect, water vapour is. There are enormous holes in the knowledge of the climate and models yet Ridley et al will argue about climate sensitivity to 2 decimal places.

      And climate sensitivity is generally expressed to 2 decimal places…
      Welcome to Lukewarmerism.

      • With a few billion more spent on this non-science, they could probably adjust that last decimal place by one number! Meanwhile the actual world make utter nonsense of their work. (But they’ll still get paid)

    • paisleyhistory…you wrote: “Lukewarmers like the GWPF are a fifth column that make real opposition look ridiculous. They do a LOT more harm than good. They look like a valid opposition but they aren’t, they’re enablers of loony alarmism who give them credibility they don’t deserve.”
      I am not sure how being opposed to ‘loony alarmism’ enables ‘loony alarmism’. But this is not about enabling or disabling anyone. ‘Lukewarmism’ is the only stance on climate that actually comes directly from the science of climate. To assert that the CO2 concentration has no impact on atmospheric temperature does not adhere to the science. To assert that doubling the CO2 concentration from pre-industrial levels will create a climate crisis, does not adhere to the science either.
      I believe my stand is close to Mr. Middleton’s: increasing CO2 is having an impact, but it is certainly smaller than natural variability and may be too small to ever be discernable. I also believe that the current warming, no matter the reason, is a wonderful thing for the majority of the living world, with perhaps a bit of an inconvenience for humans living at or below sea level if it continous (which I give just a 40% chance). The world should be rejoicing that we are returning much needed CO2 to the atmosphere.
      Nothing in my stance enables the catastrophists. I am getting the impression that you believe that admitting that CO2 has some impact, is enabling them, but I believe that arguing that CO2 has NO impact, is far more enabling. The warmists may not care about the science, and may only be interested in their agenda, but it is the science that will ultimately undermine their evil plan, not directly attacking their evil plan.

      • With respect is your position a bit of a cop-out? You say:
        ‘increasing CO2 is having an impact, but it is certainly smaller than natural variability and may be too small to ever be discernable.’
        This is the climate equivalent of having your cake and eating it. If any CO2-caused ‘warming’ really is too small to ever be discernable’ surely that’s acknowledgement that you can’t discern any – and by definition there’s zero threat from warming so small is can’t be discerned?

      • This is the climate equivalent of having your cake and eating it.

        Not at all. Liukewarmerism is the cake-equivalent of saying, “It might be a little fattening… But, I can still eat it and not die… right away.”

      • “This is the climate equivalent of having your cake and eating it.”
        Eating your cake and having it too. Claiming that something is both indiscernible and discernible is the equivalent of eating your cake and having it too. Having a cake and eating it too is standard practice with cakes, just not so common in its idiomatic usage. The notion that I can’t have my cake and eat it too is absurd and meaningless. What is reflective of the real world is that I cannot eat my cake and have it to. That’s just the way the world works.

    • Here is an exchange with Dyson
      E-mail 4/7/15
      Dr Norman Page
      Professor Dyson
      Saw your Vancouver Sun interview.
      I agree that CO2 is beneficial. This will be even more so in future because it is more likely than not that the earth has already entered a long term cooling trend following the recent temperature peak in the quasi-millennial solar driven periodicity .
      The climate models on which the entire Catastrophic Global Warming delusion rests are built without regard to the natural 60 and more importantly 1000 year periodicities so obvious in the temperature record. The modelers approach is simply a scientific disaster and lacks even average commonsense .It is exactly like taking the temperature trend from say Feb – July and projecting it ahead linearly for 20 years or so. They back tune their models for less than 100 years when the relevant time scale is millennial. This is scientific malfeasance on a grand scale. The temperature projections of the IPCC – UK Met office models and all the impact studies which derive from them have no solid foundation in empirical science being derived from inherently useless and specifically structurally flawed models. They provide no basis for the discussion of future climate trends and represent an enormous waste of time and money. As a foundation for Governmental climate and energy policy their forecasts are already seen to be grossly in error and are therefore worse than useless. A new forecasting paradigm needs to be adopted. For forecasts of the timing and extent of the coming cooling based on the natural solar activity cycles – most importantly the millennial cycle – and using the neutron count and 10Be record as the most useful proxy for solar activity check my blog-post at http://climatesense-norpag.blogspot.com/2014/07/climate-forecasting-methods-and-cooling.html
      The most important factor in climate forecasting is where earth is in regard to the quasi- millennial natural solar activity cycle which has a period in the 960 – 1020 year range. For evidence of this cycle see Figs 5-9. From Fig 9 it is obvious that the earth is just approaching ,just at or just past a peak in the millennial cycle. I suggest that more likely than not the general trends from 1000- 2000 seen in Fig 9 will likely generally repeat from 2000-3000 with the depths of the next LIA at about 2650. The best proxy for solar activity is the neutron monitor count and 10 Be data. My view ,based on the Oulu neutron count – Fig 14 is that the solar activity millennial maximum peaked in Cycle 22 in about 1991. There is a varying lag between the change in the in solar activity and the change in the different temperature metrics. There is a 12 year delay between the activity peak and the probable millennial cyclic temperature peak seen in the RSS data in 2003. http://www.woodfortrees.org/plot/rss/from:1980.1/plot/rss/from:1980.1/to:2003.6/trend/plot/rss/from:2003.6/trend
      There has been a cooling temperature trend since then (Usually interpreted as a “pause”) There is likely to be a steepening of the cooling trend in 2017- 2018 corresponding to the very important Ap index break below all recent base values in 2005-6. Fig 13.
      The Polar excursions of the last few winters in North America are harbingers of even more extreme winters to come more frequently in the near future.
      I would be very happy to discuss this with you by E-mail or phone .It is important that you use your position and visibility to influence United States government policy and also change the perceptions of the MSM and U.S public in this matter. If my forecast cooling actually occurs the policy of CO2 emission reduction will add to the increasing stress on global food production caused by a cooling and generally more arid climate.
      Best Regards
      Norman Page
      E-Mail 4/9/15
      Dear Norman Page,
      Thank you for your message and for the blog. That all makes sense.
      I wish I knew how to get important people to listen to you. But there is
      not much that I can do. I have zero credibility as an expert on climate.
      I am just a theoretical physicist, 91 years old and obviously out of touch
      with the real world. I do what I can, writing reviews and giving talks,
      but important people are not listening to me. They will listen when the
      glaciers start growing in Kentucky, but I will not be around then. With
      all good wishes, yours ever, Freeman Dyson.
      Email 4/9/15
      Professor Dyson Would you have any objection to my posting our email exchange on my blog?
      > Best Regards Norman Page
      E-Mail 4/9/15
      Yes, you are welcome to post this exchange any way you like. Thank you
      for asking. Yours, Freeman Dyson.

      • Thank you for posting this exchange Dr. Page.
        Dr. Dyson is a gentleman for whom who I have the greatest respect.
        At the risk of disagreeing with him, he is not “just a theoretical physicist”, albeit he is “91 years old” and is certainly not “out of touch with the real world”.”
        He is a man of great intellect and integrity who speaks the truth for the benefit of all humanity, despite the risks of doing so in this toxic environment of global warming extremism.

  6. The position of a geologist (I believe, from registered comments herein and my own interaction with fellow geologists, especially those familiar with sequence stratigraphy) is that the variation observed to date does not come anywhere near to exceeding the natural variation, ie, there is no actual signal detectable against the nosiey background. Whether or not there is some anthropogenic effect is not discernable, but if there is it is so small that it is irrelevant. Lukewarm then becomesa term of no scientific utility. Please do not take any of my comment as an endorsement of pollution.

    • As a geologist familiar with sequence stratigraphy, I mostly agree. Our “signal” is definitely below the resolution of the noisy background (proxy-based climate reconstructions).
      That said, CO2 is a so-called greenhouse gas, we are responsible for at least half of the rise from 280-400 ppm CO2. So, we are responsible for at least some of the warming over the past 150 years.
      Lukwwarm isn’t a term of scientific utility. It’s just a name for a category. Broadly speaking, there are three major categories:
      1) Total rejection of the so-called greenhouse effect.
      2) Lukewarmerism.
      3) Blind embrace of the CAGW religion.

      • You need a fourth:
        4) Radiatively active gases such as water vapor and carbon dioxide do play a role in air temperature but the CO2 increase is of negligible impact so human impact by this manner is also negligible.

        • I would put this group into the “Lukewarmer” category… It’s pretty close to my own position. Maybe I need to devise a numerical scale.

      • David, while I find you to be a rational geologist I think the statement of “three major categories:” is an opinion. The question is this: What is the net effect of anthropogenic CO2 in the atmosphere, considering forcings and feedbacks? Neither you nor any other scientist can answer this as the total earth environment is so complex it is essentially chaotic. So we are left to look at useful, repetitive, signals, and these are shown to us by sequence stratigraphy. This says nothing anthropogenic is detectable in the total earth environment.

        • Of course it’s an opinion. All labels are opinions.
          If it was possible to answer all of those questions, we wouldn’t need any labels.

      • “So, we are responsible for at least some of the warming over the past 150 years.”
        The real question is, is that “some” either discernable or measureable?

      • I would say that the impact of CO2 won’t be discernible until we have a much, much greater handle on the many natural variabilities.
        With a couple hundred years of good quality data, we may be able to get a good enough handle on the size and timing of the various natural cycles that we will be able to tease out the CO2 signal from the mess.

      • David,
        You said, “Maybe I need to devise a numerical scale.” Make sure it is logarithmic, like the Richter Scale.

      • True Mark. And add to that that we are still not, to this day, collecting ‘good quality data’. At least I assume our climate data isn’t good quality, since they keep needing to adjust it.
        Which brings me to what it would take for me to turn from Lukewarmer to alarmed. The Alarmists would need to go 6 full years without needing to adjust the temperature record.

      • The effect of increased CO2 in the atmosphere is not as in models, which imply highly positive feedbacks. But most likely, in the actual, complex climate system, net feedbacks are negative, so the GHE of more CO2 is negligible at best.
        Rather than lying in IPCC’s range of 1.5 to 4.5 degrees C per doubling of CO2, the actual figure, in so far as ECS exists at all, is 0.0 to 2.0 degrees C, ie net negative to very slightly positive, from the lab value of 1.2 degrees C.

        • Without a doubt, the feedback mechanisms are, at worst, only slightly positive and most likely neutral to strongly negative.

      • David,
        Your assessment then would imply a range something like 0.0 to 1.5 degrees C, with the possibility of even a cooling effect, ie -0.5 to 1.5 degrees C. I’d second that estimate.

      • David,
        While a narrow range, I’d zero in on that, too.
        IMO it only stands to reason that net feedback effects should be at least slightly negative. The models ignore or downplay the negative feedback effects of water vapor, eg evaporative cooling and possibly clouds, while concentrating on its radiative effect.
        I’m not sure that increased water vapor is even in evidence as a result of more CO2. Nor is man-made warming from the GHE evident at the one place it ought to be seen most starkly, ie the South Pole. No warming there at all in a good, long record.

        • I tend to agree that the feedback mechanisms can’t be positive. Otherwise, Earth should have already experienced a runaway greenhouse climate at some point in the Phanerozoic.

      • The heat loss from the planet during a typical nightside utterly dwarfs any CO2 effect. That only leaves daytime as a potential warming factor via heat retention due to CO2.
        There are almost no trends recognizable in daytime highs anywhere in the world, so that effect is not visible. The only place where daytime highs might be setting records with any frequency is in the Arctic. Since we have very poor records of this area it is difficult to say. Also, Arctic temperatures are greatly effected by the ice condition, varying from a marine climate to the cold, dry desert that comes when the ice is at maximum extent.
        At present we have low ice extent and the warmer, marine climate prevails North of 60.
        The ocean temperatures have been reduced by the cooling effect of the open water and now the ice is growing again.
        This will lead to a maximum ice extent and much colder Arctic temperatures.
        As the Arctic region is responsible for much of the observed warming of the period from 1980 to 2000, and that has come to an end, we now have 18 years of no atmospheric temperature increase.
        The next phase is maximum ice extent and lower temperatures in the North, which will translate into lower temperatures worldwide.
        This is the nature of the 60+ year cycle. The pseudo-scientists who inhabit the climate mainstream could have found this if they were actually looking for cause and effect. They decided on a cause before they pretended to look. They continue to feast off pretending to look.
        I consider many of them to be criminals.

      • You need to include a “No evidence of a net gain in heat in the Earth’s atmosphere via CO2” catagory.
        That’s better than total rejection (because their is no evidence it might not happen in the future), and it is a little more skeptical than the Lukewarmer position, which assumes some warming (without evidence).
        I’m a “Show me the Money” kind of skeptic.
        You wouldn’t think that would be hard to do for the 97% who push CAGW. But to date, no evidence, one way or the other.
        We don’t know what CO2 is actually doing to the atmosphere, and anyone who says they do, are wrong.

      • David Middleton
        Do you have a proof that humans are responsible for at least half of the rise from 280-400 ppm CO2 ?
        At least half of the rise from 280-400 ppm CO2 would mean humans are responsible for major portion of the increase in CO2 during the last 150 years.
        You qualify for the third category instead of second category !
        3.Blind embrace of the CAGW religion.

      • David Middleton wrote: “I tend to think that the true TCR is 0.5-1.0 C”
        Thank you David – I tend to think climate sensitivity to CO2 (“ECS”) is between 0C and 0.5C. I dislike the term “luke-warmist” because it contains the odious term “warmist”. 🙂
        From a political standpoint, our positions are similar – IF humankind is causing some global warming, it is NOT catastrophic (and is probably beneficial, imo).
        Furthermore, increases in atmospheric CO2, whatever the cause, are clearly beneficial to humanity and the environment. CO2 is not alarmingly high in the atmosphere, it is alarmingly low – for the continued survival of terrestrial carbon-based life on Earth.
        BUT from a scientific standpoint I have some concerns:
        I proved in January 2008 (published on icecap.us) that CO2 lags temperature at all measured time scales, from ~~300 to 800 years in the ice core record to ~9 months in the modern data record, on a shorter time cycle. The proof is that dCO2/dt changes ~contemporaneously with global temperature, and its integral atmospheric CO2 lags temperature by about 9 months. Here is an approximation: http://www.woodfortrees.org/plot/esrl-co2/from:1979/mean:12/derivative/plot/uah5/from:1979/scale:0.22/offset:0.14
        If ECS was significant, CO2 would not lag temperature at all measured time scales and this close relationship would not be apparent in the data record.
        My conclusion does NOT mean that current temperature change is the only or even the primary driver of increasing CO2 – other major drivers of increasing CO2 could include fossil fuel combustion, deforestation, deep ocean exsolution of CO2, etc.
        Humlum et al published a conclusion similar to mine in 2013, but the climate science community is only now starting to openly discuss this subject – I think it is important, far too important to be ignored.
        Best regards, Allan

      • David,
        You say “The change in the 13C ratio is consistent with the volume of CO2 that humans have released from geologic sequestration.” Consistent with (in terms of direction of change,which is the usual argument, not “volume”)… then yes, atmospheric 13C ratio is going down and this is “consistent with” the incremental CO2 having a 13C ratio lower than the current atmospheric value. Is that what you are saying? if so, no dispute. If you want to say that the decline in 13C RATIO is aligned with what we would expect if it was caused by burning fossil fuels alone then I have to disagree. Not only do the data tell us clearly that the 13C ratio of the incremental CO2 is -13 per mil (as opposed to fossil fuels at -26 to -28 per mil), the latest Keeling paper (discussed here quite recently) actually recognises that the models do not match the data.
        The discussion of the latest Keeling paper is here:https://wattsupwiththat.com/2017/09/12/study-plants-are-globally-getting-more-efficient-thanks-to-rising-carbon-dioxide/

      • David,
        Thank you for your prompt response. What you need to look at is a plot of d13C against 1/CO2 (I showed an example on the previous thread). If the incremental CO2 has a constant d13C content (on average), the plot will be a straight line. It is.
        A quote from the Keeling et al (2017) paper:
        “Using updated records, we show that no plausible combination of sources and sinks of CO2 from fossil, fuel, land, and oceans can explain the observed 13C-Suess effect unless … (insert new, novel, extra- complexity excuse)”. It is incredibly simple to explain the observed decline of atmospheric d13C … it is that the incremental CO2 has, on average, a d13C content of circa -13 per mil. The issue here is explaining WHY it is -13 and not -28. The models used by Keeing et al are not able to explain this any longer because the models are based on assumptions that would lead to a change in d13C content (of the incremental CO2) over time, which does not appear to be happening. They therefore introduce a new variable, previously assumed to be constant, that can be used to ensure a match. Speculation, not science.

        • Very interesting. I will definitely check it out. I wonder how this affects the ice cores? The d13C has routinely been cited as a “human fingerprint.”

      • Sorry, David, I forgot answer your final question. I am a bit reluctant to stray into areas well beyond my expertise, but I can show evidence that the incremenental CO2 has had a d13C content of circa -13 per mil since 1850 or earlier (but not tonight!). This does not tell us definitively what the source is, but it is interesting that it appears to have been about the same for such a long time (relatively speaking).

      • David, the ice core data are remarkably consistent. I will post some plots tomorrow, but would greatly appreciate your independent “peer” review. I believe my view on the recent d13C content being -13 per mil is not in itself controversial, but is somewhat “hidden” in the literature and the models used to explain it are (as I noted) are getting more and more complex. I can provide references when I have time.

      • David,
        I am sure you are familiar with much of the background, but I can provide more detail if you would like. The data shown below are monthly “seasonally adjusted” from Scripps Institute of Oceanography, which means that the annual cycle has been removed. In the case of the South Pole, this is a very minor adjustment but provides better resolution of the longer term trends. The data source (downloaded on 20170501) is:
        First, monthly atmospheric data plotted against time (δ13C data only available since 1977):
        Second, δ13C plotted against 1/CO2:
        The intercept of the linear trend line (-13.02 per mil) reflects the average content over the time period. If the incremental CO2 had a constant δ13C content it would be a simple linear relationship, but it is not a fixed value over the shorter term because it decreases significantly (becomes more negative) during an El Niño and increases with a La Niña. Still, it does support the view that in the longer term it has been the same value on average. The underlying mathematical basis for the relationship between δ13C and 1/CO2 is sometimes referred to as the Keeling equation, with the graph itself being referred to as the Keeling plot. See here for more details:
        I have just noticed that the above reference shows the intercept for the Law Dome ice core data to be -13.1 per mil (see Figure 1) so I hardly need to bother with the next section!
        For a more recent version of ice and fern data from Law Dome and South Pole, I used the Supplemental Information from the following paper:
        Adding these data to the above plot gives:
        The atmospheric data (in blue) are a copy of the previous plot and the trend line for the ice and fern data is based on that data alone, so the two lines are independent of each other. Although these ice and fern data must be subject to greater uncertainty than the atmospheric measurements, the similarity of intercepts is remarkable.
        One final plot is one that has been shown on WUWT many times, but I do not recall any references to the choice of scales:
        The left scale is linear in δ13C but, to get alignment with the CO2 data, the author has quite rightly used a right-hand scale that is linear in the reciprocal of CO2 which reflects a constant δ13C value for the incremental CO2! Further, we can compute that value simply by comparing the two scales: taking 1/CO2 values of .0035 and .0029 (right scale) and reading off the equivalent δ13C values (outer left scale) of -6.47 and -7.56 respectively gives a constant δ13C value for the incremental CO2 since 1750-1800 of -12.8 per mil. Close enough to -13, I think you’ll agree.
        As noted before, the observation that the δ13C of the incremental CO2 is around -13 per mil is not controversial in itself and is an input to the climate models. The following paper illustrates a possible explanation on Figure 5.
        Note that the gradient of the black vector is -38/3 (see text below figure), i.e. -12.7 per mil, and the primary adjustment to get to that value requires a major flux of 13C through ocean disequilibrium (difference between δ13C going in and δ13C coming out). Not impossible, but how likely is this multi-variable model to satisfy the consistency of the long term trend seen in the data. Which brings us back to the Keeling et al (2017) paper mentioned in my earlier comment where their complicated model was unable to match the δ13C observations until they invented a new variable.
        In summary …
        The reasons that I feel uncomfortable with the “settled science” view are (i) that there seems to be a reluctance to openly discuss and explain the facts regarding δ13C and (ii) the models are based on parameters that are almost certainly changing with time (e.g. the δ13C content of fossil fuels) and are getting more and more complicated with additional variables being introduced (as per the Keeling et al paper referenced in my earlier comment), in stark contrast to an apparently very simple and stable relationship shown by the data.

      • A small correction to my comment above that “the δ13C of the incremental CO2 is around -13 per mil is not controversial in itself and is an input to the climate models” is not exactly what I meant to say. Some “static” models (based on an annual balance of CO2 and δ13C) use this fact as an input constraint (e.g. Randerson et al, 2002, referenced above), whereas more complex time-variant models (e.g. Keeling et al, 2017, also referenced above) may generate a δ13C profile as an output … and then find that it does not match the observations.
        My main point, however, is that there seems to be a tendency by some settled science proponents to intentionally mask the true facts by using phrases like “consistent with” when the reality is that the data do not actually match what is implied by that statement. Some “lukewarmers” who have not studied a particular aspect in depth may be tricked into thinking such an issue has been “proved”.

  7. Not a lukewarmer.
    Would lean more towards AGW hypotheses on the date that the Pro-AGW people make their own case, purely by Science, devoid of all influence by talking heads, journalists, communicators, pollsters and the rest of the social riff raff like economists, lawyers and bureaucrats who seek to make a living from the derivatives of other peoples’ Science.
    If the Science is good and pure, present the Science with purity, let the scientific process run its usual course of hypothesis testing, then publish only when the work is done so well that proper, formal error estimates put on it allow determination of whether it is significant and can be acted on with a high degree of confidence.
    So far we have had endless episodes of Flying Circus Science.
    Now let us have the few percent of that Science that might pass those tests be identified and the rest scrapped.
    The concept of lukewarmer has no place in good pure Science which is devoidd of emotion and personal belief. Geoff

  8. The theory that CO2 warms the atmosphere is unproven because the feedback is unknown. And more than half the instrumental era data show it is false : before the 1950s where data show stable CO2 but increasing temperature and from the 1950s to the 1970s where data show increasing CO2 but there was a global cooling hysteria.
    So no, lukewarmism is not well-grounded in science and is not legitimate.

    • And we do have the real problem of “adjusted” surface temperature claims. There is so much infill, done by a non-blind process, that the expectations of the researcher have a free run. This situation is like N-rays or counting human chromosomes at best.

      • BINGO!
        In the what we know, don’t know and know we don’t know departments, feed backs and “Corrections” are big players. Are feed backs positive or negative? Are the “Corrections” legitimate or subject to bias?
        The corrections obviously follow a pattern that would suggest bias. That we know. Too many people think they are legitimate.
        We should know that we don’t know the sign of feed backs. Too many people think they know it’s positive.

      • There is no “control” for the experiment required to just what Man’s CO2 is doing to the planet.
        The closest we had was the past temperature records which Hansen has fiddled with.
        Call up current records of past temperatures online if you want but they are not what they used to be.

      • I would describe myself as a lukewarmer, as in Matt Ridley’s description.
        And agree that natural variability has a larger impact than the human component, even (or especially) in the Arctic, where the amount of sea ice loss has happened MUCH FASTER than predicted.
        Arctic species have had to adjust to much larger and faster changes than have occurred to date (or predicted for the near future) and they would not have survived as species if they had not had the capability to successfully adapt.
        Susan Crockford, zoologist

      • That’s simply a function of natural variability being far larger than the human impact.

        This is a logical fail.
        If natural variation is larger than human impact, it is impossible to determine whether there is any human impact at all.
        I have often made the point that Climate Sensitivity to CO2 can only be determined by actual observation of Earth’s atmosphere and empirical data obtained therefrom, and we will never be able to extract the signal to CO2 (if any at all) until such time as we know and understand everything there is to know and understand about natural variation, its constituent components, and the upper and lower bounds of each and every one of the constituent components of natural variation. It is only then that we will be in a position to eek out the signal from the noise of natural variability.
        The real problem we face is the poor quality of our data sets, and the problem caused by scientists not wanting to collect and use high quality data, but rather to seek to make do with poor quality data and making adjustments thereto with the hope that a silk purse can be made from a sow’s ear. This approach will not work as the error bars/uncertainties are too great.
        I think that we can, at this stage, say something about Climate Sensitivity, and that is if our data sets are good with low error bars since it is not possible to extract the signal to CO2 from these data sets, Climate Sensitivity to CO2 (if any at all) must be small. If on the other hand our data sets are poor with wide error margins, then the possibility exists that Climate Sensitivity to CO2 (if any at all) could be as large as the error bounds of our data sets.

        • Actually, we would only need to nail down a climate sensitivity value.
          The radiative forcing effect of CO2 has been measured. It more or less matches the theortical value.
          However, the translation of Wm-2 to K is complicated by the complexity of the atmosphere and oceans.
          The fact that we can’t diffentiate our contribution from the natural variability doesn’t negate our contribution.

      • richard, that is not correct. We can detect small signals in the presence of large signals. In engineering we do it all the time. What is needed is a solid knowledge of all the signals in a system.
        At present, we do not understand the large (natural) signals sufficiently. As a result, the CO2 signal is smaller than the error bars on the natural signals. This is what makes it undetectable at this time.

      • Actually, we would only need to nail down a climate sensitivity value.

        How do you nail down climate sensitivity if you cannot observe it, ie., if you cannot eek the signal out from the noise?
        What is the reason why no standard text book that lists the properties of CO2, states that one of the properties of CO2 is that per mole of CO2 causes X degC of warming?

        • I didn’t say it would be easy. The radiative forcing bit can be reasonably nailed down. However, in order to translate that into temperature change, there would have to be more than 1,000 years of precise instrumental data.
          And, until the day that someone can unequivocally fill in the blank…
          A doubling of atmospheric CO2 will cause the lower troposphere to warm by ___ °C.
          AGW will remain a hypothesis.

      • The problem is this.
        Have a look at the above plot, and one will note that the temperatures in 1878 to 1879 changed by 1 degC, ie., from an anomaly of -0.6degC to +0.4 degC.
        Whilst we do not know how much CO2 increased between 1878 and 1879, our best guestimate would be only a small fraction of a ppm which could not have driven much of a temperature rise. This means that natural variation can be in the order of 1 degC. Indeed, we see this type pf warming with El Nino events, and we have no idea what drives El Nino (but it is not CO2).
        Given that natural variability is so large, until we get a proper handle on natural variability we will never be able to identify this event as something other than natural variability.
        The signal is completely lost in the noise of natural variability.

      • I didn’t say it would be easy. The radiative forcing bit can be reasonably nailed down. However, in order to translate that into temperature change, there would have to be more than 1,000 years of precise instrumental data.

        I’ve done this based on the seasonal cycle. I know how much sun is at toa, and what an atm-less surface would have. And I know how much temps change at that exact same place. We get a defined change in forcing daily, and we have millions of records.
        My process only works outside the tropics, and this is a daily change in temp, divide by 24 to get the instantaneous value in Degree F per 1W/m^2
        These are by latitude bands for land stations. All of the raw data and code is available in SourceForge

      • Sjc
        But do you not see the problem that arises when you think of believe a matter is correct, when there is no way to show it is.
        It does not advance the science when you adopt and publicise a stance like lukewarmer based on belief.
        There can be no progress about global warming big picture until a way is found to separate natural from anthro. All that can result is backward progress countered by valid rebuttal. Which, for which we thank you, is precisely what you have been doing, thankfully with impact. Geoff

    • Feedbacks either reduce or amplify the impact of CO2. They can’t negate it altogether.
      All of the science to date indicates that the climate is regulated by multiple strong negative feedbacks.

      • Mark
        This depends whether you define a feedback as a feedback to CO2, or a feedback to warming.
        What is there to prevent a doubling of CO2 causing a warming of 0.3 degrees, and a rise in temperature of 0,3 degrees to create more cloudiness resulting in a reduction of temperature of 0.3 degC such that each effectively cancel the other out, resulting in no net change.
        That would mean that in Earth’s system, the climate sensitivity to CO2 would be zero.

      • “They can’t negate it altogether.”
        Actually, they can, if there is an integrating element in the feedback loop. See “PID control”.

      • Richard, there is no such thing as a feedback to CO2, there is only feedback to warming.
        If warming caused an increase in cloudiness, which then caused the temperature to drop back to what the temperature was prior to the warming, then the cloudiness would also drop back to what it was.
        For there to be an sustained increase in cloudiness in this scenario, there must also be a sustained increase in temperature.

      • Forest, if the feedback caused more cooling than the initial warming, then the feedback would disappear since it was caused by the warming in the first place.
        For an integrating element to work, you need an external source of energy.

      • Another way to put it is that the energy that drives the feedback comes from the signal. The feedback can’t have more energy than the signal that is driving it.

      • Integration requires only non-dissipation. Nothing is ever totally non-dissipative in this entropy dominated universe, but it can be as close to it as makes no practical difference.

      • Mark,
        As Richard so accurately points out, and as you acknowledge, warming/cooling effects are not direct feedbacks to CO2. But, just because these aren’t, doesn’t mean that CO2 itself doesn’t have a feedback mechanism. In this case, I suggest that plant life would be the appropriate analogous feedback mechanism to consider. And given that there are different uptake rates (plant growth) from release rates (plant decay) it’s entirely possible (or, at least plausible) that a CO2 feedback could result in a end point (defined simply as the point in time when you took the measurement, since there’s no real ending) lower than your initial start point. I think that’s one of the fundamental aspects of non-linear systems. Even if we take that our climate isn’t perfectly chaotic, in that it seems to be strongly damped and bounded, it’s still non-linear and can surprise us with results that don’t follow from our simplistic linear thought processes.

  9. As a lukewarmer myself, I estimate human contribution to global warming as about one third, based on comparisons of the effects of last warming push (1975-2003) to previous ones. This assumes natural warming has continued at the same rate. As we cannot estimate natural variability during this time, we don’t know if it is a little more or a little less.
    I would become alarmed if the rates of change increased significantly over the next couple of decades. I would think I might be wrong if the rates of change don’t decrease over the next couple of decades compared to the 1975-2003 period.
    Nothing will make me think that human emissions don’t have an effect on climate, since the evidence for that already has been produced.
    This is my view of future temperatures by 2025:
    If I am way off then I don’t understand it. If I am spot on it could still be luck.

    • Javier, in 2025 we will be on CMIP11 and HadCRUT9 so you will need to adjust your “Observations” line down some pre 2015 and up post 2015.

    • Those CMIP5 RCP4.5 numbers are NOT accurate with respect to the 1961-1990 mean.
      The 2016 RCP4.5 average, for example, is +0.85C in the 1961-1990 base period.
      In fact, even the Hadcrut4 numbers are not right with respect to the 1961-1990 base period.
      That is the issue with so many of these graphs from the warmists. They mix up base periods to show an inaccurate but appealing to their audience view.
      These are the accurate numbers for RCP4.5 with respect to 1961-1990.
      Hadcrut4 here.

      • Hi Bill,
        I checked the data and you are correct. Ed Hawkins figure is wrong. The CMIP data has a different baseline, and in the figure it is compressed, looking more similar to the observations than it really is. I will make a new figure with the correct data.
        From now on I won’t trust Ed Hawkins.

          • Maybe, but the mistakes always go in the same direction. If they make a mistake in the opposite direction they quickly realize.
            I’ll try to have a correct figure by tomorrow, here, with the climate explorer data, in case you want to use it.

          • No problem. Actually it was less work than I thought. Here you have:
            It is obvious that the models, even with RCP4.5, believe we are stuck in a permanent very strong El Niño that is getting worse with time. I guess that’s what the people that programmed the models thought was going to happen.

      • Bill Illis,
        Thank you for stressing this large incompatibility of graphs showing differences between CMIP and observed.
        Steve McIntyre did several pieces on this on Climate Audit. Nic Lewis also.
        One piece is at https://climateaudit.org/2016/04/19/gavin-schmidt-and-reference-period-trickery/
        The other matter with large uncertainty is the observed temperatures after about 2000. Graphs showing temperatures using the Karl adjustments have different conclusions to others, such as satellite temperatures. Only one can be correct. Which is it? We should not tolerate loose science where pro AGW people look at Karlised and sceptics look at AUH, then go their separate ways with opinions. One will be wrong.

    • I’ll be convinced the globe is warming when it unequivocally gets warmer than the Eemian(last interglacial. At best the ice core records show that the current interglacial isn’t cooling as fast as the Eemian did.

    • Try not to take this personally. Lukewarmism is applied both ways: for the cause and the effects – leaving the public mystified. All climate change is 100% natural.
      >> Mankind has no large scale enduring influence on temperatures. None. <<
      "Lukewarmism' is bad word usage leaving too many unanswered questions swept under the rug for the sake of conformity. Lukewarmism is going along with absolutely phony science – it is a 'go along' consensus groupthink construct. It is warmism-lite; lukewarmists utilize the same groupthink herding/blocking tactics as the warmists.
      Lukewarmists will eventually be identified by the public as wrong wrt the human-caused climate connection, as it is now a matter of peer-reviewed science that solar activity causes warming and cooling, and that the sun caused the 20th century warming, the post 1976 warming, and the 2015-2016 ENSO.
      CO2 does not control temperatures, it’s the other way around.
      Contrary to AGW theory, rising CO2 did not warm the ocean or land during the 30 years of cooling after 1945. Lukewarmists have the same intractable problem as warmists in using manmade CO2 emission theology to explain the three different rates of warming under increasing CO2 over decadal scales.
      The sun alone causes warming, cooling, and extreme events, not CO2!
      So Matt Ridley – lukewarmism is wrong on causation. All climate change is natural. 100% natural.
      CO2 warmism has technically already bit the dust so why do skeptics keep it alive?
      Were the recent hurricanes 33% manmade too?

      • Lukewarmists do not claim that CO2 controls the climate. That’s the alarmist position.
        Lukewarmists acknowledge that CO2 has an impact on climate, but it is one of many such influences and far from the most important one.

      • “Lukewarmists do not claim that CO2 controls the climate. That’s the alarmist position.”
        When someone claims to be a lukewarmist and assigns 33% of warming to mankind, then it is clear lukewarmers DO attribute CO2 as a temperature controller, albeit not 100% but still a major controller of temps and therefore of climate.
        See the duplicity?

        • No. I don’t see any duplicity. Anthropogenic CO2 could be responsible for 33% of the warming since 1950 or even 1850 and still not be a major controller of the temperatures or the climate.
          The warming since 1850 has only been in the neighborhood of 1 C. This has had relatively little impact on the Earth’s climate.
          Humans might be responsible for 1/3 of a minor bit of climate change.
          CO2 isn’t the control knob. It’s more like the treble dial.

      • The warming since 1850 has only been in the neighborhood of 1 C</blockquote.
        Have a look at the (old) HADCRUT4 plot. Apart from the recent strong El Nino (2015/16), temperatures are only about 0.1 degC above that observed in 1880! ie., around an anomaly of +0.5degc compared to the 1880 anomaly of + 0.4degC.
        If the current forecasts for a La Nina at the end of this year/early 2018 are correct and a La Nina develops, then by April/May 2018, it is likely that we will see that current temperature anomalies will again be only about 0.1degc above those observed in 1880!

    • Except for the fact that what you have graphed as “observed” bares little resemblance to reality.
      Who knows where that maladjusted sequence of non-data will end up !!

    • HadCRU is a pack of lies.
      There is no actual evidence that human activities, which both warm and cool, have had any measurable effect on global average temperature or any other planetwide climatic phenomenon, with the possible exception of cleaning the air since the ’70s, which China and India are now dirtying again.
      Urbanization, irrigation and other human activities have affected localities and regions, but these activities haven’t yet added up to a detectable global effect, in part because what we do cuts both ways. We can’t even know the sign of any net human effect.

      • Sixto, you are welcome to believe whatever you want. I have researched the issue with the same care I put on past climatology, reading hundreds of scientific articles on the issue, and checking the data. I am convinced that the effect of human emissions on climate is clear, but it is not overriding natural variability.

      • I agree with Sixto on this basis:
        Evidence does not exist to show warming caused by humans
        The warming we have seen is not outside past natural variance limits
        No indication that this recent warming trend, which stopped around 2000, isn’t already over.
        No reason to think it is not just a continuation of the trend out of the LIA
        No explanation for the LIA, just persistent attempts to cover it up, which is not science ( certainly no indication that CO2 or lack thereof,had anything to do with it)

      • Javier,
        Please state the evidence that you have found for a human fingerprint on global climate since c. AD 1950, or whatever point at which you think our influence became detectable.
        It doesn’t matter how many pages IPCC reports have or how many papers you’ve read. I have yet to find convincing evidence for the alleged human fingerprint. I’ve been looking since the 1980s and still haven’t found it. Maybe I haven’t read the papers which you have, so I’d appreciate knowing what has convinced you that a human influence is detectable.

        • “Fingerprints” aren’t often a feature of sciences so dominated by non-uniqueness. We have moved a fair bit of carbon out of geologic sequestration into the active carbon cycle. An increase in radiative forcing, correlative with the increase in atmospheric CO2 has been measured.
          Now, the degree to which that can be translated into a percentage of the warming since 1950 is very subjective.

      • David,
        How do you separate and increase in radiative forcing from more H2O in a warmer world from a possible effect of man-made GHGs?
        How do you show that whatever manmade warming there might be isn’t from cleaner air rather than more CO2?
        I repeat. There is no dispositive evidence whatsoever that man-made CO2 has had any measurable effect on “climate”. How then to justify dismantling industrial civilization?

        • Sixto… You and I both know that dispositive evidence isn’t exactly the norm in Earth and Atmopsheric science. Non-uniqueness dominates this field.
          And… I don’t justify dismantling industrial civilization… I agressively oppose it.
          I just recognize the fact that humans have played a small role in recent climate change.

      • “I am convinced that the effect of human emissions on climate is clear,”
        Would you mind pointing out to me how you reach this conclusion?

      • Sixto,
        It is hard to write in a comment what has been distilled from scores of articles and data, and at the same time be convincing to people that don’t want to be convinced. Anthropogenic warming is somehow of a different nature than natural warming. It essentially affects minimum temperatures more than maximum temperatures. It seems to affect night temperatures more than day temperatures. It appears to affect winter temperatures more than summer temperatures. It appears to decrease the rate of cooling more than increase the rate of warming. It appears to be more global while natural change is more regional.
        And the most sensitive aspect of anthropogenic warming are glaciers. Experts agree quite unanimously that globally glaciers have not been this reduced for thousands of years. About 5000 years ago appears to be the time when glaciers were this short. And that is the reason many things buried in ice thousands of years ago are appearing now. Like Ötzi, the ice man from Tyrol, that is ~ 5200 years old. Some people believe this means our temperatures are like 5000 years ago. On the contrary I think glaciers are specially sensitive to CO2. The air above glaciers is very cold and very dry. The lower amount of water vapor makes it more sensitive to the increases in CO2. Despite higher winter precipitation and no appreciable changes in snow cover, the mass balance of glaciers is very negative.
        Real skeptics don’t subscribe to any particular belief. They just trust the evidence. We have lots of evidence that our emissions are affecting the planet. Mostly in a good way by increasing the photosynthesis and decreasing water loss by plants, increasing forest biomass, increasing carbon sinks. That they affect also our climate is mostly a given. The warming is only partly caused by our emissions, and has some good aspects, as the higher temperatures are mostly beneficial, and there is a reduction of many extreme weather manifestations. It also has some bad aspects as everything in life. Heat waves are to become more frequent with higher temperatures, and high precipitation events also, as a warmer climate is a more humid climate.
        When you see somebody embracing every positive aspect of CO2 and rejecting every negative aspect, he is not a skeptic. He is just a different type of believer.
        A figure recently published by the UK Met Office that I modified to show a rule of thumb estimation of anthropogenic warming:

      • Javier,
        I’d be glad to be convinced. There just isn’t any dispositive evidence. You see what you want to see.
        Your example of glaciers doesn’t wash. What we actually see in glaciers is that those which have indeed retreated are where they were in previous naturally occurring warm cycles. For example, those Swiss passes which are only open during warm cycles show artifacts from Oetzi’a time at the end of the Holocene CO, from the Minoan, Roman and Medieval WPs. Perhaps you’re unaware that the ice in which Oetzi was found had moved downhill, so his remains have nothing whatsoever to say about the relative warmth of his time and now. The Holocene CO was demonstrably warmer than now.
        Why should glaciers be especially sensitive to CO2? No evidence supports that article of faith.
        When and if the Current WP ever shows three 50 year intervals warmer than the three 50 years intervals still warmer than any such interval in the Current WP, then maybe we can talk and try to tease out any human influence. But so far the Current WP has been cooler than the Medieval WP, as it was cooler than the Roman and the Roman was cooler than the Minoan. Hence, no detectable human influence.
        Thanks very much for presenting what you think is evidence of man-made global warming due to CO2, but to me it’s not convincing and actually not even evidence.

      • David,
        No I am not.
        Javier presents no evidence. Just observations which he interprets as evidence.
        Retreating glaciers reveal forests 1000, 2000 and 3000 years old. Less rarely the 5000 years which he finds to be evidence for a human fingerprint in the current warming.
        IMO the preponderance of evidence shows that the Current Warming has so far been cooler than the previous warming cycles. Hence, no human fingerprint from higher CO2.
        Science doesn’t do “proof”, although colloquially that term is sometimes used. It does confirmation and falsification. There is no evidence confirming the hypothesis that man-made CO2 has warmed the planet globally. And the hypothesis is easily shown false by every possible line of evidence.

        • Observations are evidence. That said, this is 100% correct…

          The preponderance of evidence shows that the Current Warming has so far been cooler than the previous warming cycles.

          I don’t find the glacial retreat to be particularly compelling… But we have moved a fair bit of carbon from geologic sequestration into the active carbon flux. An increase in radiative forcing, generally consistent with our CO2 emissions has been measured. While not “proof,” this is evidence that we have contributed to the warming over the past 50-150 years.

      • David,
        As I mentioned previously, allegedly greater radiative forcing (a dubious claim) is not exclusively consistent with more CO2. Better or at least competing explanations exist, as I pointed out.
        For example, Gore claimed that retreating ice on Kilimanjaro was evidence of “global warming”. But there had been no local warming and deforestation was a superior explanation for that observation.
        Similarly, Javier supposes that an alleged (by Warmunistas) exceptional net glacial retreat offers some kind of “evidence” of man-made global warming. But all the evidence in the world shows that supposition not to be the case. There is no evidence that temperatures now are higher than in prior warming cycles, nor any physical basis for the unsupported assertion that glaciers are particularly responsive to CO2. Were that the case, then the land ice which matters most, the EAIS, would not be gaining mass.

      • David,
        My response is lost in cyberspace. This happens so often, that I’m probably going to quit commenting here.
        I hope it does eventually show up, but even if it doesn’t, I’ll add that if glaciers were indeed super-sensitive to CO2, then they should all be retreating, which of course they aren’t. Major glaciers and every continent are advancing.
        The same applies to the mass of the land ice formation which matter by far the most, ie the East Antarctic Ice Sheet.

        • Sixto,
          I hope you don’t quit commenting here. Comments sometimes get caught up in moderation for odd reasons. Believe me, the current system is far more efficient than it was just a few years ago.

      • Sixto,
        The evidence you are NOT looking for is obviously in scientific articles.
        1. J. Oerlemans. Holocene glacier fluctuations: is the current rate of retreat exceptional? Annals of Glaciology, Volume 31, Number 1, January 2000, pp. 39-44(6)
        “Integrations for a 10 000 year period, driven by random forcing of a realistic strength, show that the current retreat cannot be explained from natural variability in glacier length and must be due to external forcing.
        2. Johannes Koch, John J Clague and Gerald Osborn: Alpine glaciers and permanent ice and snow patches in western Canada approach their smallest sizes since the mid-Holocene, consistent with global trends. The Holocene 2014 24: 1639
        “Glacier retreat in western Canada and other regions is exposing subfossil tree stumps, soils and plant detritus that, until recently, were beneath tens to hundreds of metres of ice. In addition, human artefacts and caribou dung are emerging from permanent snow patches many thousands of years after they were entombed. Dating of these materials indicates that many of these glaciers and snow patches are smaller today than at any time in the past several thousand years.”
        “The global scope and magnitude of glacier retreat likely exceed the natural variability of the climate system and cannot be explained by natural forcing alone. This departure is best explained by the ascendancy of another forcing factor – the increase in carbon dioxide and other greenhouse gases in the atmosphere.”
        3. Goehring, B. M. et al. 2012. Holocene dynamics of the Rhone Glacier, Switzerland, deduced from ice flow models and cosmogenic nuclides. Earth and Planetary Science Letters 351–352, 27–35.
        “After 5 ka, the Rhone Glacier was larger than today, but smaller than its LIA maximum extent. The present extent of the Rhone Glacier therefore likely represents its smallest since the middle Holocene and potential climate warming will lead to further rapid retreat of the Rhone Glacier.”
        4. B. K. Reichert, L. Bengtsson and J. Oerlemans: Recent Glacier Retreat Exceeds Internal Variability. Journal of Climate 15 (2002) 3069.
        “Preindustrial fluctuations of the glaciers as far as observed or reconstructed, including their advance during the Little Ice Age, can be explained by internal variability in the climate system as represented by a GCM. However, fluctuations comparable to the present-day glacier retreat exceed any variation simulated by the GCM control experiments and must be caused by external forcing, with anthropogenic forcing being a likely candidate.”
        5. O. Solomina, W. Haeberli, C. Kull, G. Wiles Historical and Holocene glacier–climate variations: General concepts and overview. Global and Planetary Change 60 (2008) 1–9
        “The finding of the Oetztal ice man in the uppermost part of a small glacier in the Austrian Alps clearly illustrates that Alpine glacier volumes (not lengths!) have become smaller now than during at least the past about 5000 years.”
        6. Bakke, J., Lie, Ø., Dahl, S.O., Nesje, A., Bjune, A.E., 2008. Strength and spatial patterns of the Holocene wintertime westerlies in the NE Atlantic region. Global and Planetary Change 60, 28–41
        “The retreat of maritime glaciers along western Scandinavia over the last century is unprecedented in the entire Neoglacial period spanning the last 5200 yrs.”
        A) Koch & Clague 2006 meta-study of global glacier extent showing that current retreat exceeds the global range and minimum extent trend since mid-Holocene (Trend lines added). Notice how it shows glaciers now shorter than Medieval Warm Period and Roman Warm Period.
        Koch, J., & Clague, J.J. 2006. Are insolation and sunspot activity the primary drivers of Holocene glacier fluctuations? PAGES News, Vol. 14 No 3 pp 20-21.
        B) Thompson et al., 1995 study of the Huascarán glacier. Ice-core of the glacier with the temperature proxy showing that current glacier temperature is unprecedented for thousands of years and anomalous within trend.
        Thompson, L.G. et al. 1995. Late Glacial Stage and Holocene Tropical Ice Core Records from Huascaran, Peru. Science vol. 269, 46-50.
        Organic remains entombed in ice at mid-Holocene and freed by present global warming.

      • David,
        Worse is hard to imagine. But even when I copy and repost, many comments never show up. For long ones, it’s frustrating.
        I have other things to do, and can’t afford to waste time, especially when so few people are liable to read my comments even when they do show up.
        Plus, it’s disturbing that so much creationist cant is allowed here. It only reinforces the arguments of my acquaintances who equate CACA skepticism with creationism as equally anti-scientific.

        • I share your concerns. The only thing I can say, is that I hung around here long enough and behaved well enough that my comments don’t get moderated. Anthony wants to encourage a stimulating and wide-ranging debate… Charles and the rest of the moderating team are extremely fair and they don’t actively try to censor oponions with which they disagree.

        • Also… bear in mind that everyone here is a volunteer… Or, in the case of Anthony Watts, actually sponsoring this awesome blog.

      • Javier September 25, 2017 at 6:24 pm
        I know that too many links is a no-no, but those do usually appear after moderation. What bugs me is how many comments without any offending material simply disappear, never to reappear.

      • micro6500 September 25, 2017 at 6:25 pm
        Correct. Slightly warmer winters and nights is exactly what happened during prior warming cycles, with also perhaps some slightly higher summer day maxes. So how was the late 20th century warming any different from the early 20th century warming and the late 19th century warming, coming out of the LIA?

      • David,
        I’ve been squelched for disrespecting “people of faith”, ie those who try to defend the Bible as science. I’ve seen others leave this blog because of its promotion of creationism.
        I’m glad that you don’t get moderated, but I have been. Repeatedly. And other Christians who understand that the Bible isn’t science, but have been accused of being atheists because we know that fact.

        • Sixto,
          I don’t agree with that. There is a general rule here that the C vs E “debate” is unwelcome… largely because it results in flame wars.

      • David,
        Yet again my comment has disappeared in cyberspace, without mention of moderation.
        I’m outa here.
        (I have looked through the Spam and Trash folders, NONE of your missing comments are there,could be a problem at your end?) MOD

      • My understanding was that Oetzi’s body was in a naturally formed hollow, and as a result the flow of the glacier went over him. He was found pretty much where he died. If he had been caught up in the glacier itself, he would have been expelled after just a few hundred years.

        • I suspect that if that were not the case, the body would not have been in such pristine condition, and the associated artifacts would have not been so close by.

      • Javier, I was responding to Sixto’s claim that Oetzi’s body had been caught up in the glacial flow and had been found downhill from where he died.

    • Forrest,
      I don’t know how the calculate the error, but if we can put little faith on the temperature values, much less on the error.

      • Hi Forrest,
        The models never converge. It is little known, but if instead of anomalies, absolute temperatures are used, the models are all over the place, as they don’t agree on the temperature of the planet. They are aligned by anomaly at their multidecadal baseline. In this case 1961-1990, but there is no point at which they converge.

    • What happens to this trend if its extended back to 1930? Back to 1650? This is just the tail end of a longer trend that absolutely has nothing to do with CO2 levels, at least before 1950. As such, I cannot ascribe any of it to CO2. It is only hypothesis. Perhaps only conjecture.

  10. Whenever anyone, whatever technical background he or she has or does not have, says, “Accept the Science,” I stop reading. Science is not something to be accepted. Science is comprehended or not comprehended.
    As a mechanical engineer who has dug into atmospheric radiation at length, I have learned that CO2 is already saturated less than three meters from the surface, and all this absorbed infrared radiation is immediately thermalized. So, the significant warming occurs only at the Top of Atmosphere, where 400 ppm has raised the altitude at which the atmosphere can radiate freely to space. How far was it raised, and how much more heat does the atmosphere contain since it is now radiating to space at a slightly lower temperature, and what did this do to the lapse rate? NO ONE CAN CALCULATE THIS.
    Thus, all attempts to define Climate Sensitivity are based on the assumption that all warming since 1850 has been caused by CO2. Since this is a baseless assumption, no one has ever correctly calculated Climate Sensitivity.

    • +1
      It does appear that there should be a small team of engineers validating the claims made by academic scientists, who, contrary to normal science, seem eager to prove rather than falsify their hypotheses.

    • Thus, all attempts to define Climate Sensitivity are based on the assumption that all warming since 1850 has been caused by CO2.

      Take that as your baseline. Recent climate sensitivity estimates put the TCR and ECS respectively at about 1.35° C and 1.75° C.
      How much of the warming since 1850 has been due to the recovery from the Little Ice Age and other natural drivers? It’s almost certainly greater than zero… It’s probably at least 50%. I think it’s about 75%. Adjust TCR and ECS for the natural component and you get:

      % Natural TCR (° C) ECS (° C)
      0% 1.35 1.75
      25% 1.01 1.31
      50% 0.68 0.88
      75% 0.34 0.44
      100% 0.00 0.00
      • There is no way to learn whether it is 0% or 100%. We don’t really know why the temperature is what it is, now, much less what it will be in 100 years. In this area one man’s opinion is as good as another’s. Destroying prosperity seems like a poor option in this ambiguous environment.

      • David
        Sorry to say that when I read your comment it appears that there is a lot of thinking where the word is being used as guessing/believing.
        Whilst what you say may be reasonable, it may even be correct, but it is not science. There is nothing that displaces the null hypothesis that all observed change (if any change has been observed) is of natural origin.

        • CO2 is a so-called greenhouse gas.
          Humans are responsible for at least half of the rise from 280-400 ppm CO2.
          The radiative forcing effect of rising CO2 has been measured.
          So it’s simply a statement of fact that humans have contributed to the warming of the past 150 years.
          The degree to which we have contributed is probably unknowable, without a definitive climate sensitivity value. The fact that the climate isn’t behaving in a significantly relative to the last 2,000 years, seriously constrains the significance of our contribution.

      • CO2 is a radiative gas, but that does not mean that it has any warming effect on a water world that is all but opaque to DWLWIR, and in Earth’s convective atmosphere.
        Whether in Earth’s system, CO2 cause any warming, can only be determeined by observation, and to date no warming signal has been observed. That is why the IPCC does not state what the ECS (or TCR) is for CO2, and why it puts forward a speculative range. It is the reason why no standard text book that lists the properties of CO2, states that CO2 per mole results in X degC of warming. No one has made any measurement, so it is an unknown quantity, meaning that it might be zero.
        You probably know that the Martian atmosphere has an order of magnitude more CO2 molecules than that in Earth’s atmosphere (if I recall correctly it has about 14 times as many CO2 molecules on a numerical basis). The CO2 molecules are more tightly spaced to one another in the Martian atmosphere (because Mars is a far smaller sphere), and therefore the prospect that LWIR emitted from the Martian surface being captured by a CO2 molecule in the Martian atmosphere and then a photon being re-radiated from that CO2 molecule and subsequently captured by another molecule of CO2 in the Martian atmosphere is far higher than the incident in Earth;s atmosphere, and yet Mars has no measurable radiative GHE. Why is that?
        Even NASA concedes the reason why Mars has no measurable GHE is because the Martian Atmosphere lacks mass/lacks density/lacks pressure. NASA do not claim the reason why Mars has no measurable GHE is because the Martian atmosphere lacks molecules of so called GHGs.

      • “Destroying prosperity seems like a poor option in this ambiguous environment.
        Fixed that for you, Michael Moon 🙂
        Or, “Destroying prosperity seems like a poor option in this ambiguous environment except to progressive watermelons” also seems about right…

      • CO2 is well mixed, water vapor is mostly in the lower atmosphere and even then concentrated around the tropics.
        In the areas where there is lots of water vapor in the air, CO2 has little to no impact.
        In the areas with little water vapor in the air, it has more of an impact.

      • MarkW,
        That should be true, but isn’t. The one region on earth where CO2 should outshine H2O is the South Pole. But it doesn’t, or at least hasn’t despite decades of the best possible observations.

      • Sixto, while the stations we do have in the Antarctic are top notch, there are about 2 orders of magnitude too few of them to support the claim that we have excellent data regarding what is happening down there.
        Secondly, you still have the problem of CO2 not being the only thing that influences temperature.
        You keep trying to prove that just because the CO2 signal is lower than the natural signal, that this proves there is no CO2 signal.

      • “The radiative forcing effect of CO2 has been measured. It more or less matches the theortical value.”
        What now? CO2’s “radiative forcing effect” is to raise the altitude at which the atmosphere can freely radiate to space. How does one measure that? As I explained, CO2 absorbs IR from the ground and thermalizes it within a few feet of the ground. At TOA, CO2 absorbs and re-radiates IR, making an opaque layer to 15-micron IR, which breaks up at some altitude. The higher this altitude goes, the lower the temperature at which the atmosphere radiates freely to space goes. Radiative heat transfer is of course determined by the temperature difference, which when radiating to space at Absolute Zero is the temperature of the gas radiating.
        The CERES satellites would need to have a spectrograph capable of a line-by-line analysis of IR emitted by the atmosphere to be able to begin to measure this, which they do not.

  11. Lukewarmer that thinks the small amount of warming caused by Anthropogenic CO2 is mostly positive and the atmospheric CO2 increase itself is clearly positive for mankind and the earth bio environment as a whole. BAGW Beneficial Anthropogenic Global warming. As I say over and over there is no C in AGW.

    • BAGW…good description. We have to dispel the notion that CO2 is a pollutant. Otherwise soda drinks will be next on their hit list. Or by their reasoning then they should be, just to show how absurd some of the CAGW meme is becoming.

      • Forrest
        They clearly want to reduce the number of humans on this planet into the millions to save it, so my guess is they already have come to that conclusion what’s 6 or 7 Billion people when you’re talking about saving the polar bears from having to change their diet a little.

      • Yes. I suppose that I have to put myself in the Lukewarmer camp, since the increase in atmospheric CO2 appears to have an anthropogenic component, and the effect of additional CO2 is non-zero. I agree, I’m a “never-minder” when it comes down to cases, leaning to “yeah!” for a greening earth.

      • Yep. It’s real… But it mostly doesn’t matter to humans and it REALLY doesn’t matter to the planet.

    • False dichotomy.
      There is no reason why “We’re all gonna die” and “CO2 has no impact” should be the only options.

      • Not correct by a long shot. All we can say with any certainty is that the CO2 signal is less than the very noisy natural change signal. This is not proof that there is no CO2 signal, no matter how much you may wish it to be true.

      • MarkW,
        Critics do not have to show there is no CO2 signal.
        Global warming advocates have to show there is one.
        They have failed to do this.
        Normally that would be game set and match. Natural wins.
        But the game rules get changed when the topic is green house guesses. Geoff

      • Warmists need to show that there is a CO2 signal and that it is large enough to worry about.
        My only issue is with the religious belief that it is impossible for CO2 to have any impact on climate.

  12. I am a complete laymen but I actually think lukewarmers do not help in the climate debate. If the global warming theory had not been espoused I would challenge anyone to understand whether the weather or climate had actually changed in the last 60 years. Certainly I don’t believe that the increase in CO2 is directly corelatable to temperature . I would argue that in the real world the only influence on temperatures are natural , whether that be sunspots, natural cycles or whatever. The only contribution that man has made to the temperature has been the obvious and clear amendments to historical and current data that has been done to suit the political narrative. It is clear this unexplained, arbitrary and suspicious manipulation of data represents at least 50% of the rise and perhaps as much as 100%. It is only a matter of time before a whistleblower exposes this deliberate and insidious fraud.
    I think that rather than Lukewarmers rather than becoming warmists as the fraud becomes more evident they will become more passionate full blown skeptics. But even if lukewarmers don’t change the one area I do agree with them is that attempts to change the future climate, through taxes, or blowing up coal fired power plants or blighting the landscape with windmills or solar panels are doomed to fail and won’t impact on future temperatures.

    • Most skeptical climate scientists are Lukewarmers. Craig Idso, Roy Spencer, Richard Lindzen and Judith Curry have all calculated climate sensitivities to CO2 that are above 0 C.

      • Did they all calculate the SAME value? Can we have a list with figures against names? (Just for amusement you understand, not going to run a sweepstake just yet).

      • David, that is just more of “believe these smart people”. This site consistently proves that science is not about belief. It is about questioning. I’m not going to agree with you because other smart people do, and I’m disappointed that you would suggest it.

      • “Craig Idso, Roy Spencer, Richard Lindzen and Judith Curry have all calculated climate sensitivities to CO2 that are above 0 C.”
        Yeah, but these *estimates* keep going lower and lower every time they look at them. How low can they go? Zero is a possiblity, wouldn’t you agree?

    • Agreed! I can’t tell today’s weather from the 1970’s and I challenge anyone to say different anywhere in the world. Zero noticeable change in 40 years is a pretty damn poor catastrophe and precious little indication that anything is exceeding the potential of a system we barely (if at all) understand. Politics cum religion dressed up as science.

    • “I would argue that in the real world the only influence on temperatures are natural , whether that be sunspots, natural cycles or whatever.”
      That is the correct attitude for this subject. Heating and cooling of the atmosphere are from Mother Nature until proven otherwise.

      • “That’s as ridiculous a position to take as is the claim that CO2 is 100% responsible for the changes.”
        It’s ridiculous to say it’s all Mother Nature until proven otherwise? That position doesn’t eliminate the possiblity that CO2 has some effect, all it says is until you have some evidence CO2 *does* add net heat to the atmosphere, you should go with Mother Nature as the cause.
        There is NO evidence that human-caused CO2 is adding any net heat to the Earth’s atmosphere, so that leaves Mother Nature as the driver.

  13. I’m a lukewarmer. For example, I think evidence shows we are growing more food with more CO2 in the air, and warmer temps in places like Russia, which just had record harvests. Positive effects should not be ignored when striking a balance. Many deserts are getting a bit greener.
    Here is what would cause me to move toward alarmism:
    1. Evidence that cyclones (hurricanes in N America) are getting larger in area, are more likely to be class 4 or 5, and drop more rain than in the past, to the point where hurricanes become considerably more economically damaging than in the past. This applies to cyclones world wide.
    2. Evidence that very damaging (economically) weather extremes are becoming more common. Things like 20 inch rainfalls in 2/3 days in places that almost never used to get them. Or having such events occur fairly frequently in places where they had previously been rare.
    3. Evidence that sea level rise is accelerating.
    Of these 3, I think acceleration of sea level rise is least likely, I think it will remain close to about a foot a century, possibly even less. But I could be wrong, obviously.

    • Obviously, none of those is evidence of climate change. Literally none. They are “symptoms” of climate change, but could be symptoms of something else.
      I can spin scenarios where the trends for each of those phenomena would be higher or lower sans climate change. For example, as the Antarctic is what is known as an “artic desert”. Very little precipitation. As the air warms, even slightly, we could see more snowfall in Antarctica. Given this is the largest mass of land bound ice on the planet, this could reduce sea level rise.
      So sea levels could rise…or fall with warming.
      Damaging weather extremes? our record is spotty, and also there are more of us, with more infrastructure to damage, then ever before. Therefore economic measures of weather extremes are meaningless.
      Storms form due to the difference in temperature between two areas (that is how “work” is created). Given climate change predicts the poles will warm faster than the tropics, this would reduce the temperature differential, reducing the size, and power of storms. So more storms = global cooling.
      So, no, none of those phenomena definitively prove anything.

  14. Ron Long has said it all. The climate is changing and it behooves us that windmills and solar panels are going to prevent climate change because the climate is going to change regardless (as that is what it does). All the citizens of earth (not just the rich countries) deserve cheap and reliable energy, cheap and reliable clean water. Give them both these things instead of devoting vast, copious, egregious sums of money to silly schemes that do nothing. Frack the gas, dig the coal and do it responsibly with minimal pollution but mostly do it for all those much less fortunate citizens of the planet to raise their living standards.

    • Lomberg calculated that for the amount of money we spend each year trying to avoid a trivial amount of warming, we could provide clean water to every person on the planet.

    • I think this sums up how most of us feel about the issue. Fantastic waste of resources for negative return in human terms, and hardest on the poor.

  15. The 2016 El Niño should spike toward the top of the 2σ range, not toward the model mean.

    Excellent point. I am looking forward to reading your next post.
    Just a nick pick, though. Should it be “models mean” instead?

  16. Sort of like AA: My name is Roger and I am a lukewarmer.
    I would be inclined to alarm if the match between observed temperatures and model projections trends to a match over the next ten years especially because I worry that the temperature trend will be down.
    Even in that case though, I don’t see any possible solution to the alleged problem simply because replacing fossil fuels is so expensive that the cure is worse than the disease. I think fossil fuels are the best thing that ever happened to mankind so even if there are problems with its use using fossil fuels we can afford to adapt to the problems.

  17. The gas pressure, volume, mass and temperature are connected. pV=nRT. Alarmists don’t need anything more than to show gas composition having a meaningful role in it.
    In the meanwhile the effect of parts per million variations in the atmospheric composition on temperature is equivalent to homeopathy. Even without e.g. sudden changes in the volume none seems to be able to explain. https://science.nasa.gov/science-news/science-at-nasa/2010/15jul_thermosphere.

    • Thanks for the inspiration. I hereby lay claim to the new word;
      ————————- THERMEOPATHY ————————–
      25th September 2017 21:12hrs UK
      The Reverend Badger.
      THERMEOPATHY – the scientifically nonsensical claim that small variations in trace gases in a planetary atmosphere can have a significant effect on surface temperature of the planet.

  18. Essentially, catastrophic alarmism is based upon the RCP8.5 pathway scenario, but observational warming is closer to the RCP 2.5 pathway scenario,
    The author states:

    Actual emissions are tracking closer to RCP 6.0. When a realistic transient climate response is applied to RCP 6.0 emissions, the warming tracks RCP 4.5…

    Whilst the first figure supports that claim, it is so only because of the very recent warming associated with the strong El Nino of 2015/16, and it is material to bear in mind that the ENSO cycle has not yet completed and should a La Nina develop (as forecasts presently suggest for late 2017/early 2018), the temperature anomaly will then fall back so that temperatures/warming will once again be tracking the RCP 2.5 pathway scenario, as they were tracking in 2013/14 prior to the recent strong El Nino and when the pause was still current and being discussed in the literature.

    • I didn’t phrase that very well. I was referring to model projections.
      When I apply a TCR of 1.35° C to the actual emissions, I get a model trend that matches RCP 4.5. If TCR is substantially less than 1.35° C, the climate could easily track RCP 2.5.
      The temperature observations have consistently tracked strong mitigation scenarios going all the way back to Hansen et al., 1988.

        • There is no boundary. CO2 causes warming; however it is a diminishing returns function. Each additional ppm CO2 yields less warming than the previous ppm.
          Now, it is quite possible that the sum of the feedbacks could be so negative, that it totally offsets the CO2.

  19. Typical babbling nonsense from a science illiterate — how could we ever simply toss out the 9,200 peer reviewed papers in the last IPCC report they ask. Well, Google Scholar brings up 365,000 papers when searching for ‘Steady State Universe’, what does this suggest to them I wonder?

    • No it was the favoured model pre 1940and will included physics greats in the list like Einstein. I suspect more will be for the model than against, which was killed rather fast by a single observation rather than a prolonged debate.

    • And new evidence indicates that the SuperNova measurements that are a foundation of the expanding universe idea may be radically wrong! Where will we go from there? The brains working on astrophysics are constantly rediscovering physics while the pontificating pinheads of mainstream climate science can’t see past their puffed out chests.

  20. I’m sorry, but this article by Middleton leaves me slightly ill. The question is simply, are lukewarmers allowed to have different opinions? Yes, we are allowed to have different opinions. “Legitimate” implies we are deranged, or unscientific. Nothing could be further from the truth.
    Lukewarmers are firmly within the predictions by the IPCC, but they are at the low end of the spectrum.
    The question is really to catastrophic climate believers: what are your proposed solutions, what will they cost, and will they absolutely work? At some sort of marginal cost, I might say, well, I could be wrong, and a bit of insurance is probably worth it. Unfortunately the minute a catastrophic climate believer starts talking about solutions they begin to sound like deranged lunatics. None of their proposed solutions will work, and none can by applied without spending money we don’t have. Literally their solutions are insane. Which circles back to, who is legitimate in their beliefs and who is not? people who propose solutions that obviously won’t work are the “rational” ones?

    • Legitimacy of Lukewarmerism doesn’t delegitimize other positions.
      The answers to questions you ask of “catastrophic climate believers” delegitimizes their position.

      • In fact it is a solid test of their logical thinking abilities – if they can’t come up with even marginally workable solutions, then why should I believe in their alarmism?
        It like someone claiming an asteroid is about to hit the Earth. I say, okay, what should we do about it? And their response is “think happy thoughts.”
        At that point I might decide to go back and re-check their calculations regarding the asteroid.
        And by the way, I would accept “I don’t know” or “there doesn’t appear to be an easy solution” as a legitimate answers from catastrophic warmers. But I never hear that. What I do hear is nonsensical garbage – opposition to fracking and nuclear power, support for unreliable renewables that can’t possible solve the problem, and dreamy statements about magical future technology that will save the day.

    • This is mainly where I have moved to. Arguing about numbers that we literally cannot know is pointless, and the only “proof” we will ever actually get as to who is right is what happens to the climate over the next 10-100 years.
      What I deeply object to is the lunacy of moving from “there might be a problem” to wholesale mass lunacy based on debased economics and mass wishful thinking. I have lnked to this above, but everybody should read it:

    • You must have better hearing than I do, Geoman. I hear energy poverty and the death of Western civilization by economic suicide.

  21. What am I? I accept that the Earth has warmed slightly since the 1800s, but there is no attainable scenario that would make me become an alarmist. I believe that all Warming is essentially good.
    Global Warming does not constitute a Universal or Comprehensive Problem. There are Pros and Cons associated with every type of Climate, be it Hot, Cold, or anything in between. But the fact remains – it is scientifically evident from the fossil record and real world observation that the advantages associated with a Warmer Climate far outweigh the disadvantages.
    I am for Global Warming. I am Pro-Warming. I want more Warming. Warming is GOOD.

    • 20C of warming would not be good. However there is no viable scenario for that to happen until the sun goes into it’s red giant phase.

  22. “What evidence would push you toward alarmism?”
    I consider myself a lukewarmer, however; while the effect of incremental CO2 on the equilibrium surface temperature is finite, it’s definitely not a significant contributor and at most is a minor second order effect.
    ‘Evidence’ in the form of trends, real or imagined, is insufficient to change my mind as the constraints imposed by the laws of physics are immutable and those constraints require the sensitivity to be less than the lower limit claimed by the IPCC. Any ‘data’ evidence to the contrary is either mischaracterized, misinterpreted or maladjusted.
    The ONLY thing that would change my mind is the discovery and validation of new laws of physics that override the constraints imposed by Quantum Mechanics, the SB Law and Conservation of Energy.

    • The new laws of physics you seek have already been done – see classic K-T diagram. Heat transfer from cold to hot, radiative fluxes added by simple math and result used to compute temperatures via SB. All the new, exciting and innovative distortions of previous scientific knowledge you could possibly want contained within CAGW. You just have to BELIEVE it ! Simples !!

      • RB,
        The problems aren’t with using arithmetic to add radiant fluxes or considering that the transfer of energy by photons is independent of the temperature of the emitting or absorbing bodies (which BTW is NOT heat transfer from cold to hot).
        Adding radiant fluxes is perfectly valid since one Joule is no different from any other, thus superposition applies. The cold heating hot argument is bogus since it only applies to a 2-body system and not to the sum of absorbed energy emitted from multiple sources (in this case, the Sun and the atmosphere).
        SB is an immutable law of physics and using it to convert equivalent emissions into an equivalent temperature is also valid. The ONLY average temperature with any correspondence to reality is the equivalent SB temperature corresponding to average emissions.
        Besides, when these principles are properly applied, the calculated and verifiable sensitivity is between 0.2C and 0.3C per W/m^2 and not between 0.4C and 1.2C per W/m^2 as claimed by the IPCC.
        The get the wrong answer because they DO NOT apply these techniques to derive the sensitivity and instead just assume a very high one. This high sensitivity came along with the establishment of the IPCC which required a sensitivity that large in order to justify their creation. They haven’t corrected it since because to do so eliminates their reason to exist and if there’s one thing bureaucracies are really good at, its self preservation.
        The real problem is a conflict of interest where the IPCC has become the arbiter of what is and what is not climate science by what they publish in their reports, yet they require a significant anthropogenic component in order to justify their existence.

  23. I think it is possible that the additional CO2 has slightly warmed the planet. However I start from the position that we know so little about the climate that making any definitive statements on either side is ludicrous.
    One we can explain the various cycles properly and in detail, once we can use first principles to build accurate models, once we can explain the LIA and the MWP and so on – then I will listen, but otherwise we are simply mking observations and guessing.

  24. As I have said before, the alarmist package involves three assertions:
    As David points out lukewarmers dispute that 100% of observed warming is from burning fossil fuels, but think that humans make more than o%. I think it less than 20%, but the point is these are all opinions since no one has successfully separated natural and man made warming in the real world.
    As Matt Ridley points out, lukewarmers dispute the notion that warming now or in the foreseeable future is dangerous, as Richard Lindzen has also mentioned. I agree, with the proviso that we should be at least preparing infrastructure and energy resources to meet storms already experienced.
    Finally, the third leg, that governments can moderate future warming by reducing emissions, is a stretch too far for me, and I gather for most lukewarmists, even true believers like Jim Hansen.
    The problem for lukewarmers is that the alarmist/activist stool falls down with only one leg missing. And dissenting on any of the three claims gets you labeled a denier.

    • Not sure how you would classify Richard Lindzen when he says this (at the end of a recent presentation:
      I haven’t spent much time on the details of the science, but there is one thing that should spark skepticism in any intelligent reader. The system we are looking at consists in two turbulent fluids interacting with each other. They are on a rotating planet that is differentially heated by the sun. A vital constituent of the atmospheric component is water in the liquid, solid and vapor phases, and the changes in phase have vast energetic ramifications.
      The energy budget of this system involves the absorption and reemission of about 200 watts per square meter. Doubling CO2 involves a 2% perturbation to this budget. So do minor changes in clouds and other features, and such changes are common. In this complex multifactor system, what is the likelihood of the climate (which, itself, consists in many variables and not just globally averaged temperature anomaly) is controlled by this 2% perturbation in a single variable?
      Believing this is pretty close to believing in magic. Instead, you are told that it is believing in ‘science.’ Such a claim should be a tip-off that something is amiss. After all, science is a mode of inquiry rather than a belief structure.
      Can’t think of anything to add or subtract.

      • I would say it’s mostly about the ocean and secondary to the ocean, it’s mostly about the clouds.
        Lots of lukewarmers believe clouds play much larger part of the global climate, than the alarmists do.

  25. I’m a lukewarmer I guess.
    Without doing much of anything, we appear to be on track to stay within 2c, therefore I would ask for some solid science as to why we need to do more.
    I would also ask them to categorically state that they think they have oceans cycles licked and not mention them with hand waves after the fact.
    I would also ask them to initialize new models with what they know about the current ones running hot. They know its happening…
    Stop linking weather events to climate change.
    I guess, I ask for a dose of reality and then I remain open to be convinced something more drastic is needed, using models (backed up by science) that are keeping in touch with reality by something other than a mathematical coincidence.
    I would ask them to be open to Nuclear energy as being part of a solution, where appropriate (no Tsunami or earthquake active zones). Currently the climate change is unduly negative on Nuclear, because they refuse to accept it as a solution, as its a dirty word…
    I’d ask them to be objective about cleaner coal stations and ask them to stipulate where coal needs to get to before they think its acceptable.

  26. I’m totally not a lukewarmer as far as CO2 is concerned. Yes, mankind does affect the environment in a limited way with various forms of pollution.

  27. I am a Lukewarmer but more than that I am also Realist. I mean that in the sense that being from a science background I know for a fact there is a huge risk that one day we are likely going to get hit by a dam big meteor. Now if I was a climate activist I would arguing we have to get off this planet because our death is a certainty. The reality is there is nowhere safe in the universe and whatever you do will have new risks.
    The same reality exist on global warming many of the effects are slow and easier to plan to deal with rather than try and deal with directly especially since there is zero chance of getting emissions inside what they say is required. So you have new risks emerging such as social unrest and inequality divisions opening up. The divide between 1st and 3rd world have never been so wide and getting worse.
    The implementation of CAGW policy is never going to happen the world will go to war well before that point and the German election result should have made that very clear. The shear uncompromising attitude of the CAGW supporters has guaranteed it will fail because no lasting solution to any problem has ever been done by force.
    Watching the whole CAGW play out across the world is like a a slow moving train wreck. The result is never in doubt just who and how much gets smashed in the process is all that is being decided.

    • Excellent post, maybe we should rename the categories as “realist” and “unrealist.” I’m with LdB and the realists, CAGW alarmists are (you guessed it) the unrealists. They take unreal data, adjust it further from reality, and propose unrealistic “solutions”. What evidence would push me toward them? After I took the lsd, I would begin to consider the alarmist position after I read that one prominent alarmist, just one, pointed out the hypocrisy of the rest of them, published by the MSM.

      • DM: Thanks for reading, you’re right of course. So I stand with the (mostly) hypocrite-free realists; the “other” realists are awash in people who demand the rest of us do what they will not do. I know, it doesn’t solve anything, but I sure do appreciate you folks letting me post it.

  28. I am a mild lukewarmer who hopes lukewarm is real and sustaining. It has to be obvious that human kind now at 7.5 billion people on the planet will tend to cause more heating than it would cooling, all things being equal.
    However, the long term trend in earths climate is an ice age, and we are in an interglacial that has been getting progressively cooler since the higher warmths of the Holocene Optimum. All previous interglacials came to an abrupt end and this one will not be different. The return to ice age dynamics may have already begun in the dark ages, or the LIA, probably with the assistance of volcanic events. If the downward trend in temperatures continues over time as it has over the last 5000 years, then our brief fling with an earth optimum to human civilization may be coming to an end while we retreat into ice house conditions over the next century. I view warming as always better than cooling, since significant cooling will never support a planetary population where we are presently.
    I don’t understand why there is any alarmism from perhaps .7 degree warming that has maybe been partly caused by humans in the last 150 years. Especially when considered against recently coming out of the LIA when life was brutal in the cold, and a much stormier climate change of all types was the norm and much more severe than today due to a much larger temperature gradient. If we accept that adverse climate change has always been with us, then we now need to drop the term climate change, since that is just a play on emotion. Like a cookie monster is to a toddler.
    If we are to follow any precautionary principle then it must be one of vigilance of global cooling. A decadal series of volcanoes in various parts of the world would be sure to stress humanity far more than an equal amount of warming which could be mitigated for survival of the human race. Any major disruption of our food production, most of it in the northern hemisphere would cause global calamity, the likes of which the world has never known and would be a direct assault on civilization, immediately. Global warming is better than the alternative and staying static for long is not in the earths temperature record.

    • I think of a lukerwarmer as someone who thinks there could be some warming from rising CO2 levels [which in the future might be measurable]. But I don’t think a lukerwarmer is predicting that it will warm in distant future [+50 years]. I don’t expect average temperature to lower by 0.5 C within next couple decades. Or still seems to me we are still recovering from the Little Ice Age.
      But if we get significant evidence of what could cause cooling, it’s possible I change my mind- but even the approaching solar min, doesn’t change my view that we could see a drop in average temperature by as much as 0.5 C within 20 years.

  29. Alarmism over climate? Rapid onset of an ice age disrupting Northern Hemisphere agricultural production is the only climate event that alarms me.
    Why do we continue to argue about the AGW hypothesis with temperature data? The AGW hypothesis includes specific positive feedbacks (water vapor) and warming patterns (latitude and altitude) that are not happening. The hypothesis is invalid. The fact that global temperature isn’t matching the predicted values is a given. If anthropogenic CO2 is contributing to a warming climate in a significant manner, than the current hypothesis is not describing the function and needs to be withdrawn.
    If you want to be an AGW lukewarmist describe how CO2 is having a significant role without positive feedbacks, do so with a decent and defensible handling of winds and clouds, compare the modern rise in CO2 from past rises, adjust for land-use changes, determine the spatial error in climate datasets, and incorporate the benefits of rising CO2 in your analysis of its costs.

      • It should be easy enough to set up modern versions of Arrhenius experiments (that he himself repudiated later). Correct them for errors and set up a test atmosphere in a very large tank. Vary the concentrations of CO2 and warm the test atmosphere by shining infrared through it from below to and infrared transparent roof so the ‘absorption’ can be measured at each CO2 level. The experiment could even have pools of water at 15C to show how rapidly they warm or cool with downwelling infrared if there is any.
        As setting up this type of experiment is relatively trivial and yet it has not been done makes it appear the both the lukewarmers and the catastrophists do not want to have their pretty hypothesis killed by observational fact.

        • Such an experiment would actually support the alarmist position. However, the atmosphere is a wee bit more complicated than a tank of air.

      • David,
        I don’t think it would support the alarmist position – if it did it would have been done and reported by now. When an exceedingly simple experiment is avoided the immediate reason that springs to mind is that the proponents of the Catastrophic Anthropogenic Global Warming hypothesis are aware it would be falsified by experiment and therefore will not proceed with it.
        They have to show that the CO2 warms the surrounding air at a concentration of 400ppm and that downwelling infrared from the CO2 (that which is left after warming the surrounding air?) also heats the water at the base of the tank. A large CERN style chamber should be enough to allow some convection.
        The experiment will not be run as it would falsify the CAGW hypothesis.

  30. As a lukewarmer and operational meteorologist for 35 years, it seems anti scientific method/skepticism to be anything but a lukewarmer.
    I could type pages of reasons that both sides provide to support their one sided views…….many of them excellent points……..except they mostly suffer from placing the greatest weight on factors that support their view.
    The alarmists clearly suffer from this the most. To not acknowledge the Medieval Warm Period, Roman Warm Period and Minoan warm period as significant(and previous cyclic warmings), global events is blatant denial of previous natural global warming.
    To not dial in the enormous agricultural benefits of increasing CO2 on our greening planet, with its booming biosphere is more denial because it proves that CO2 is a beneficial gas(even if it is also a “greenhouse” gas too).
    Global climate models have been too warm and warming the higher latitudes decreases the meridional temp gradient, so the atmosphere does not need to work as hard to balance the heat disparity.
    What often happens though, is that when you see one side spinning the facts and science(using every natural drought and hurricane) or even lying about and discarding realities that really count, you distrust EVERYTHING from those sources.
    On the other extreme side, tunnel vision also takes over. Meteorology 101 tells us that increasing the temperature of the atmosphere 1 degree, will allow it to hold something like 4% more moisture. The physics of CO2(which some don’t believe in) tell us that increasing it, will lead to X amount of atmospheric warming.
    A warmer ocean temperature, should provide some hurricanes with a bit more fuel, even if we have not seen a trend that shows it happening in the real world yet.
    The global temperature is 1 deg. C warmer than it was and ocean temperature .5 deg. C warmer than it was over a century ago, regardless of data adjustments, what source you use, theories and models……………and nobody, anywhere has the franchise on climate science knowledge or is smart enough to separate out the fingerprint of how much was caused by humans and how much was natural.
    The higher the confidence in it being almost all from one or the other, the less open minded the scientist.
    It’s certain that climate science is being used as a political tool, as evidenced by ridiculous, non scientific agreements like the Climate Accord and Al Gores junk science movies/statements being sold as “Save the Planet” marketing schemes.
    Seeing stuff like that drives a skeptic, even farther to the other side to show how scientifically fraudulent these sources are. If your case agrees partially with these extremists, for instance, it may not have the same impact as if you just try to blow them up completely by showing the opposite of what they state and proving them wrong on as much as you can.

  31. So us lukewarmers are asked: what would make you an alarmist?
    Are alarmists asked the same question in reverse? I am aware of one example. The Royal Society were asked about 2-3 years ago: how many years does the “pause” have to last before you accept that your climate prediction models are wrong? Answer given: 50 years (that’s another 50 years, so 67 years altogether).

    • The smart alarmists just erased the “pause”… Kind of like Cadet James T. Kirk and the Kobayashi Maru training exercise.

    • That’s interesting Andrew. Did the Royal Society provide any scientific basis for that statement? I’m guessing not. Probably their answers on this valid scientific question were provided by the communications department after consulting as to what was politically appropos. Everybody duck and cover!

  32. What about the idea that climate sensitivity is on the low end of the spectrum (lower than “consensus”) ? Is that a form of “lukewarmism” ? It seems like a lot of folks might fit in that category. With the implication that any warming will not have catastrophic effects and that any cost of attempted mitigation would far exceed any benefits.
    With this definition, the difference between “skeptics” & “lukewarmers” might not really be significant.

  33. You have to love how the 1998 El Nino is now barely similar to the years that followed in the Zeke graph… and follows exactly the models’ predictions.
    Soon it’ll be drowned as if it barely happened. That’s science.

    • As I said up above. The temperature series depicted is so mal-adjusted that it bares very little resemblance to reality. That make to whole graph more than a bit of a joke.

    • If sea levels rise 10 feet, and we move up in elevation 10 feet, then atmospheric pressure where we are would be unchanged.

    • Another way to put it is that atmospheric pressure at sea level remains the same, regardless of where sea level is.

    • Let me apologize for being half right in my previous statements.
      My statements above are true for instances when the water entering the oceans are coming from acquifers that don’t subside as they are being drained, micro-comets and thermal expansion.
      In such a situation, the top of atmosphere will rise as the oceans rise.
      However, when water is coming from melting glaciers.
      Using the simplifying assumption that the volume of water equals the volume of ice it came from.
      Under this assumption, as ice melts, the oceans rise, but the top of atmosphere doesn’t change. As a result, the atmospheric pressure at any point above sea level doesn’t change as the seas rise.
      Since ice does take up a bit more room than water, when it melts, top of atmosphere would actually fall a little bit, As a result, the atmospheric pressure at any given spot above sea level will drop by an extremely small amount.
      In conclusion, what happens to atmospheric pressure at any given spot above sea level depends on the relative mix of water from glaciers vs. water from other sources.

  34. A huge fraction of the anthropogenic CO2 was released within just the last two decades. What would push me to alarmism is if we saw a corresponding spike in temperatures, with a rising oscillation, because I understand it wouldn’t simply be a smooth upward curve.
    Instead we see spikes driven by ocean heat release, and a relatively stable temperature profile. The global temp may even drop back down below what it was before this most recent El Niño spike. Who knows?
    But the theory of the CO2 control knob looks well and busted. It should be scrapped.

  35. Don’t we all understand that the oceans heat/cool the atmosphere and not the other way around? The ocean heat content is driven by solar influences. Isn’t it clear from the data that the satellite-based temperature record can be explained by the AMO. A quick look at the data from Woodfortrees (I don’t know how to post a graph) shows the relationship. There is a natural experiment in the works. As the AMO rolls over into a cool phase, the earth’s atmospheric temperature should decline. by about as much as the satellite data shows it warmed from 1979 to today.
    Obviously, there are lots of ocean currents, so there is more going on than just the AMO. The ENSO process can clearly be seen in the satellite data. However, I am willing to hypothesize that the coming cool phase of the AMO will drive the satellite data. This is a very simple test.
    Given the structure of the earth’s surface, which is dominated by water heated by the sun, I am amazed that so much of the scientific community has focused on changes in CO2 as a climate driver.
    Over the longer term, I believe the series of articles by Javier over at Judith Curry’s blog, as well as others, capture the dynamics of climate quite well.
    As an Econometrician, I am not sure I understand the lukewarmist position. The null hypothesis is that the observed temperature changes are driven by natural forces. I know of no data that causes the rejection of the null hypothesis. I, therefore, continue to accept the null hypothesis.

    • I don’t think that the null hypothesis is that humans have no effect on climate change.
      The AGW hypothesis is that humans are responsible for >50% of the climate change since 1950. So, the null hypothesis would be that >50% of the climate change since 1950 is natural.
      I think that this null hypothesis still holds.
      However, there are Lukewarmers who think that the AGW hypothesis holds.

      • Again a logical fail. This is what Hansen seeks to do.
        It is an assertion that humans are responsible for 50% of the warming since 1950, devoid of hard evidence. The assertion is based simply upon the assertion that we cannot think of any other reason for the warming apart from CO2
        Since humans were not responsible for the Holocene Optimum, Minoan, Roman, Medieval warm periods (even if these are restricted to the Northern Hemisphere there is no explanation as to how they could be so confined), or for the warming out of the LIA, or for the 1860 to 1880 warming, or for the 1920 to 1940 warming, the null hypothesis is that temperatures change, the temperature changes by natural phenomena, and all change of temperature is of natural origin unless the contrary can be established.
        What was the reason for (i) the Holocene Optimum, (ii) the Minoan Warm Period, (iii) the Roman Warm Period, (iv) the Medieval Warm Period. Further, if it be alleged that any of these events is solely a Northern Hemisphere event, what is the process and reason for that event being limited solely to the Northern Hemisphere?
        Until one can answer this, everything else is simply conjecture.
        Conjecture is not science.

      • the null hypothesis is that temperatures change, the temperature changes by natural phenomena, and all change of temperature is of natural origin unless the contrary can be established.

        Should have read:

        Given that we know that temperatures change, that temperature changes by natural phenomena, the null hypothesis is that all change of temperature is of natural origin unless the contrary can be established.

      • If you can not reject the null that all observed climate change (temperature change) is from natural sources, what sense does it make to test that 50% is from natural sources? The right statistical answer is that the AGW hypothesis as you state makes no sense. It is intellectual gobbledygook.
        Look, I certainly understand that radiative physics points to an increase in temperature from an increase in CO2. The problem is that in a free convective atmosphere the simple radiative physics doesn’t hold.
        Given how noisy the temperature data is, one can not show a statistically significant role for CO2 induced warming. The guessing game that people play in trying to assign some percentage of the change in observed temperature is foolish in my view. I also think that trying to construct a structural model of the climate is foolish. The economics profession long ago gave up structural models for time series models. I believe that is the right approach for climate as well.
        I also think I am on solid ground when I say that spectral analysis of temperature data shows no role for CO2 in explaining observations.
        If the La Nina that is currently developing holds forth, we will likely have a 20+ year record of Satellite data that shows zero warming. My educated guess is that the negative phase of the AMO coupled with low sunspot activity will put to rest concerns about CO2 induced warming. The focus, in my view, should be on the beneficial effects on plant growth from CO2 fertilization.
        I am much more concerned about earth’s declining magnetic field and the potential for a shift in magnetic poles than any CO2 or sunspot activity effects. The fact that most people are unaware of the potential for disruption from such an event is concerning.

        • I don’t really disagree with anything in your comment other than your concern about the magnetic field and polarity reversals.

      • David. You seem to be confusing opinion with science. Firstly, whatever AGW opinion is, it is diverse and constantly varying, apparently in response to repeated refutation on scientific bases. You 50% number is some sort of approximation on a moonshot of approximations. Nothing to do with science. It may be your choice to use it as some kind of reference but it has zero scientific credibility. Perhaps you see yourself as a mediator. Half a crock of crap is still carp!
        The null hypothesis doers not start at some kind of a guesstimated saw-off. It is null. Refute that or accept it with supporting evidence.
        P.S.-There isn’t any!

        • That’s their stated hypothesis. The null hypothesis to their stated hypothesis would be that humans are responsible for <50% of the warming since 1950.
          They haven't been able to knock down that null hypothesis.
          Regarding the null hypothesis that 100% of the warming since 1850 or 1950 is "natural," that null hypothesis has already been knocked down.

          First direct observation of carbon dioxide’s increasing greenhouse effect at the Earth’s surface
          Berkeley Lab researchers link rising CO2 levels from fossil fuels to an upward trend in radiative forcing at two locations
          Scientists have observed an increase in carbon dioxide’s greenhouse effect at the Earth’s surface for the first time. The researchers, led by scientists from the US Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab), measured atmospheric carbon dioxide’s increasing capacity to absorb thermal radiation emitted from the Earth’s surface over an eleven-year period at two locations in North America. They attributed this upward trend to rising CO2 levels from fossil fuel emissions.

          What was observed? A ~20 ppmv increase in atmospheric CO2 correlated with a 0.2 W/m^2 increase in radiative forcing at the Earth’s surface.
          Total insolation at the Earth’s surface ranges from 40 to 340 W/m^2 per year.
          Assuming a linear relationship of .01 W/m^2 per 1 ppmv CO2… A doubling of pre-industrial atmospheric CO2 from 280 to 560 ppmv will increase radiative forcing by 2.8 W/m^2. This is about 2/3 of the IPCC’s estimate.
          The total warming since 1850 has been about 0.7°C. Over the same period, CO2 increased by about 120 ppmv (~1.2 W/m^2).
          0.7°C ÷ 1.2 W/m^2 = 0.6°C/Wm^-2
          0.7°C ÷ 120 ppmv CO2 = 0.006°C/ppmv CO2
          This means that a doubling of pre-industrial atmospheric CO2 can lead to a maximum warming of 1.68°C… less than half of the so-called consensus estimate.
          Since my “back of the envelope” calculations assumed a linear, rather than logarithmic, relationship and that all of the warming since 1850 was GHG-driven, the actual climate sensitivity can be no more than half of my estimate… ~0.8°C per doubling of pre-industrial atmospheric CO2.
          This essentially means that the human impact on climate change is insignificant… but >0.

    • IMO the null hypothesis is that nothing out of the ordinary is happening in Earth’s climate now, hence no special explanation is called for.
      That might be a distinction without a difference, since in any case natural variation must be dominant. My formulation allows that there might be a human influence, but that it’s negligible or undetectable, whether to warm or cool on balance.

  36. Part of the problem with the lukewarmer position is that it implicitly fails to distinguish between “it rained yesterday but is sunny today. Absent human intervention, it would have been sunny yesterday and rainy today” on the one hand, with “humans are making the climate increasingly inhospitable for life” on the other.
    If the climate is within natural variability, than the possibility of human influence is meaningless. Our contribution irrelevant.
    Secondly, I want to see some humility. It seems more likely than not that the earth has been getting slightly warmer over the last century plus, but given how paltry the data is going back even a few decades, it is pure hubris to state that as fact. 150 years ago, 99% of the earth wasn’t within 100 miles of a thermometer and 99% of the area that was was not recorded with the accuracy necessary to prove the amount of warming claimed. Go back further than weather satellites, and I want to see great big error bars or I want you to sit out the conversation. The data is simply not there.
    And that’s even before getting to some kind of calculation as to human contribution (which itself needs great big error bars considering how poorly we understand the climate).
    And on to the “conspiracy” ad hominem. People act in concert all the time without there being a formal conspiracy. Give a group of people scant data and a financial incentive to find something and most will find it. That’s human nature. The claim t”conspiracy theory!” is a canard by cowards trying to avoid real discussion.

    • This summation should be in bold type on the front page of this website and sent to every media outlet with a particle of interest and integrity. And then put it up in the schools.

  37. As a frequently labelled denier, but really a luke warmer I set my metric for alarmism a long time ago (about 6-7 years ago in fact). I want the global temperatures to be above the model mean for a few years. I can’t rely on the surface temps, so I chose the higher quality satellite data.
    Now, if they change (lower) the model means, then that is different of course, but I mean the ones that are showing 2100 to be on the 3 deg + range).

    • So no science involved in your analysis whatsoever. Understood. Just don’t pretend to be anything but a full blown Warmist.

  38. A lukewarmer is someone who only partly Believes, because straddling the fence feels safer to them. Sorta like someone going to church on religious holidays, to keep their foot in the door, and “just in case”.

  39. There are so many reasons for not being persuaded by the radiative GHE, AGW (other than on a micro climatic level caused by land change usage) and CAGW, that one would have to write a book to address the issues. This enables people to have quite different and varying views as to why do not accept, or why they partially accept AGW.
    I am a sceptic which means that I am sceptical of almost all arguments in support of AGW, and sceptical of almost all arguments against AGW. But I believe in applying the scientific method including the application of the null hypothesis, and I have seen no evidence that persuades me that the null hypothesis has been displaced.
    I do not dispute the radiative properties of CO2, but that does not mean that it is a GHG. That is something that can only be determined by observation as to how it works when added to Earth’s (convective) atmosphere, and presently there is no observational evidence which has been able to isolate the warming signal to CO2 (if there be any at all). That is why I do not understand any lukewarmer who signs up to man being responsible for any warming whatsoever.
    In fact I remain completely unconvinced that there is any climate change. Temperature is of course but one property that goes to make up climate, and the various and many parameters that go to make up climate are never in stasis, and are constantly varying/meandering between upper and lower bounds. One of the central issues is what is meant by climate and what does this encompass, and I consider that this is something that has not been rigorously examined, identified and determined.
    I do not accept the rationale that climate can be assessed as the average of weather over a period as short as 30 years. That is a blink of the eye, and why should such a short period be the bench mark? From a global perspective, there may only be 3 types of climate, ie., those when the world is largely ice free, interglacials and glacials.
    Are we today simply observing the type of climate that is typical in an interglacial? Of course, during the course of the Holocene, there have been some cooler periods and some warmer periods, but heck that is simply what one would expect in an interglacial.
    Whilst I accept that the globe has warmed since the LIA, I remain wholly unconvinced by the evidence that the Northern Hemisphere is any warmer today than it was back in the 1930s/1940s. In fact, i consider that there are multiple lines of evidence that suggest that within the margins of measurement errors (including our approach to the assessment and reconstruction of data) that the Northern Hemisphere is any warmer than the 1930s/1940s. There is simply too little historic data and the coverage too sparse in the Southern Hemisphere in order to make any reasonable assessment of change in the Southern Hemisphere. Given the known problems with our data sets/the temperature reconstructions, I fail to understand how anyone can be reasonably persuaded that today is any warmer than the highs of the 1930s/1940s. That carries immense significance since some 95% of all manmade CO2 emissions have taken place since 1940.
    We are not even in a position to judge to what extent man is responsible for the rise in CO2 since we do not sufficiently understand or know the ins and outs of the carbon cycle. I consider that the evidence as a whole presents a strong case that man is responsible for much of the rise in CO2 levels, but even that is not beyond reasonable debate. For example ants and termites are responsible for the emission of CO2 and since we do not know how their numbers have changed these past 100 years, we cannot rule out even such lowly creatures from having had a significant impact.
    I consider that there has been a lamentable failure to properly identify what is the ideal quantity of CO2 for the biosphere of this planet, and what is the ideal temperature for the biosphere. I consider that the balance of evidence suggests that this planet has too little CO2, and that it is presently too cold. I consider that the balance of evidence strongly suggest that a warmer world is a better world, and that the biosphere would greatly benefit from the globe being several degrees warmer. In my opinion, this is an area where there has been far too little research and consideration, and for some unknown reason, it has been accepted that 2 degrees C poses a real threat without there being hard evidence substantiating such claim.
    Whilst I consider lukewarmers to hold a reasonable position, and one which may be right, I consider their position, as far as they accept that manmade CO2 has and is causing warming, to be unscientific.

    • An excellent summary, Richard. This covers most of the essential scientific issues in a careful and considered manner and is wholly accurate. I would disagree with your final comment however and think the lukewarmers hold not only an unscientific position but an UNreasonable one and also perhaps a dangerous one. The AGW nonsense is so full of unscientific BS that it somewhat undermines efforts to attack it when part of the “other side” have their own steaming dollops.

    • Unscientific!
      Could there be a greater insult to a complex, unproven hypothesis that calls for the overturning of the economic model that has propelled the world to never before known levels of well being and promises to do much more for all?
      Unscientific says it all!

  40. Lukewarmism cannot be legitimate. If it were there would be multiple scientific responses to the challenge laid out many times here by me and others.
    Every lukewarmer who believes in the influence of CO2 and manmade emissions has a great opportunity here to explain how rising CO2 caused a negative, then positive, then flattish rate of temperature:
    I respect Middleton but I won’t respect a non-convincing vague answer or non-answer while I’m supposed to think of lukewarmism as legitimate and superior. If lukewarmists cannot explain this glaring discrepancy in agw theory then it is not legitimate science, it is simply a prevailing popular opinion – ie groupthink.
    You all should realize there is no legit AGW answer to my challenge. From there all you need is the sense and courage to admit what the warmists won’t, that CO2 has nothing to do with driving increasing temperatures.

    • I don’t think “superior” factors into the equation.
      Most Lukewarmers don’t assert that CO2 is the primary driver of climate change. Rising CO2 didn’t *cause* “a negative, then positive, then flattish rate of temperature” change. For that matter, CO2 stopped rising and possibly fell during the late 1940’s to 1950’s.
      CO2 just modifies the equation.

      • Agree with David.
        To assume that increasing CO2 has zero effect on warming, is to not believe convincing evidence in physics of its ability to absorb infrared radiation in the atmosphere at certain bands/lines in the wavelength spectrum.
        The amount can be debated based on it being a logarithmic function, the overlap with H2O and level in the atmosphere that some bands might be saturated but the evidence of the effect is very compelling.
        I have heard a couple of theories for why this would not warm the atmosphere but those don’t make any sense to me.
        Just because we warmed before, similar to this does not mean that we are doing it exactly the same way for the same reason this time. If you can’t show the physical process that applied before and how its effecting the planet exactly the same way this time, then its not enough proof to rule out the possibility of other factors this time.
        Ocean cycles or sunspot activity or galactic cosmic rays are great theories that have merit and for sure something caused those previous warmings……….and they really did happen but in the absence of tying the physics together to account for all of the warming then with all of the warming now, it is impossible for me to ignore the well known physics of CO2.
        I am confident that the last 40 years have featured the best weather/climate and CO2 for life on this greening planet since at least the Medieval Warm Period. If we asked life to testify, most of it would be asking for more CO2.
        However, humans that live along coasts have the most at risk, should the warming continue. I have been surprised that sea levels have NOT accelerated higher. Maybe the increased evaporation from the oceans into an atmosphere that holds 4% more moisture has increased rains, that are going into the booming biosphere and increasing soil moisture on a global scale that is acting as a negative feedback.
        This is based on the slight, mostly beneficial warming so far. If we warmed another 1 deg. C in the next 80 years, along with another 120 ppm CO2, most life would not complain and world food production/crop yields would continue higher.
        Will that accelerate sea levels a bit?
        Not sure but 1 inch/decade right now, equates to around a foot in 100 years and that is slow enough for adaptation. I also don’t believe the crapola that today’s CO2 emissions stay in the atmosphere for a century.
        Predictions of the rate of decline for Arctic sea ice and accelerating sea levels, like global climate model temperature projections, have under performed so far.
        However, to ignore the decades long trends in those metrics, which still have not been broken, despite periods of no trend or briefly, counter trend is to ignore fundamental trend analysis.
        One difference between an “alarmist” and a “lukewarmer” might be the expectations of the steepness of the slope of those trends.
        With regards to taking actions to cut CO2 emissions, it might end up being the dumbest idea in human history, considering the cost and the massive benefits that increasing CO2 is bestowing to life.
        Benefits are 10 times the negative consequences to life right now. If the negative consequences, (based on my lukewarmer speculative scenario) get up to being equal to the benefits in 50 years, why would we spend trillions of dollars now, in case that might happen?

      • “To assume that increasing CO2 has zero effect on warming, is to not believe convincing evidence in physics of its ability to absorb infrared radiation in the atmosphere at certain bands/lines in the wavelength spectrum.”
        That’s only half the story. CO2 does what it does in the atmosphere, but when it does what it does, there could be negative feedbacks which could completely negate CO2’s effect on net heat of the Earth’s atmosphere. CO2 is not acting by itself, it has to play ball with the rest of the atmosphere.
        Noone can say definitively that CO2 creates a net increase in the temperature of the Earth’s climate, just by being present.
        BTW, talking about the benefits of CO2 to plant life is a distraction from the debate and probably gives some people the idea that if increased CO2 increases plant growth, then it must be doing other things in the atmosphere, too. These are different phenoneon, which are conflated together too often.
        As for CO2 enhancing plant growth. I’m a believer because the evidence is obvious. That can’t be said for CO2 and Earth’s temperature.

      • CO2 didn’t rise during the first half of that cooling period, despite increasing emissions. MacFarling Meure et al., 2006 found possible evidence of a mid-20th Century CO2 decline in the DE08 ice core…

        The stabilization of atmospheric CO2 concentration during the 1940s and 1950s is a notable feature in the ice core record. The new high density measurements confirm this result and show that CO2 concentrations stabilized at 310–312 ppm from ~1940–1955. The CH4 and N2O growth rates also decreased during this period, although the N2O variation is comparable to the measurement uncertainty. Smoothing due to enclosure of air in the ice (about 10 years at DE08) removes high frequency variations from the record, so the true atmospheric variation may have been larger than represented in the ice core air record. Even a decrease in the atmospheric CO2 concentration during the mid-1940s is consistent with the Law Dome record and the air enclosure smoothing, suggesting a large additional sink of ~3.0 PgC yr-1 [Trudinger et al., 2002a]. The d13CO2 record during this time suggests that this additional sink was mostly oceanic and not caused by lower fossil emissions or the terrestrial biosphere [Etheridge et al., 1996; Trudinger et al., 2002a]. The processes that could cause this response are still unknown.
        [11] The CO2 stabilization occurred during a shift from persistent El Niño to La Niña conditions [Allan and D’Arrigo, 1999]. This coincided with a warm-cool phase change of the Pacific Decadal Oscillation [Mantua et al., 1997], cooling temperatures [Moberg et al., 2005] and progressively weakening North Atlantic thermohaline circulation [Latif et al., 2004]. The combined effect of these factors on the trace gas budgets is not presently well understood. They may be significant for the atmospheric CO2 concentration if fluxes in areas of carbon uptake, such as the North Pacific Ocean, are enhanced, or if efflux from the tropics is suppressed.

        From about 1940 through 1955, approximately 24 billion tons of carbon went straight from the exhaust pipes into the oceans and/or biosphere.
        The mid-20th century cooling simply overwhelmed the effects of CO2 emissions. The cooling was so pronounced that the atmospheric concentration may have even btiefly declined.

      • Bob, all you have proven is that CO2 is not the only driver of climate and that there is at least one driver that is more powerful than CO2. Despite your desire to believe otherwise, you have not proven that CO2 has no role in the climate.

      • “Bob, [1] all you have proven is that CO2 is not the only driver of climate and that there is at least one driver that is more powerful than CO2. [2] Despite your desire to believe otherwise, you have not proven that CO2 has no role in the climate.” – MarkW
        [1] Certainly glad to see you agree there is a driver greater than CO2.
        [2] I never claimed it had no role in the climate. It is a response to temperature change, not a driver of it. CO2 enhances leaf area which indirectly is important to climate but not in driving temperature.

  41. So much great stuff in this post and comments. I would just add:
    1. There may be nothing worse than thinking you know something when you don’t actually know that specific thing. Socrates is supposed to have said that skilled carpenters tend to think they know everything–especially what to do in politics. Skilled modellers?
    2. I gather from the many smart people or experts here: effect of man-made CO2 on temps almost certainly not zero. Very likely to be less than 50%, likely to be no more than 30%.
    3. Regardless of what this exact number is, what are the alternatives? Life without fossil fuels? As they used to say on rude blogs: bwahhahahaha. Bring on nuclear plants at a realistic cost, methane hydrates.
    4. New study suggests increase in CO2 will help produce more plants, bigger, etc., but nutrition in plant food will decline, as it tends to do whenever output per plant is increased by selective breeding or whatever. Is GMO food the solution?
    5. We spend a lot of time on small things: I like the suggestion that temps only went back up to the mean of the models because of El Nino in 2015-16; by rights it would have been predicted that observations would have been even higher, so models that don’t include El Nino are still running too hot. I look forward to ten more years of data, and more posts.

  42. I’m old. I live in Minnesota. It’s certainly getting warmer around here. I’ve lived long enough to see it. In Saint Paul, they used to build ice castles for the Winter Carnival. I’ve seen pictures of the late 1800s castles – they were enormous and elaborate. When I was paying attention in the 1960s and 1970s, I kept hearing about the troubles they had with the castles melting. The planned 2017 ice “castle” is despicably small. They’re talking about a giant castle for 2018 (the first since 2004), but “Recent warm winters have the Winter Carnival folks exploring options for building a massive ice structure, Bump said. They looked at an “alternative panel system,” which didn’t work out, she said.” http://www.twincities.com/2016/12/29/st-paul-winter-carnival-ice-castle-2018-super-bowl/
    There’s no way I can ignore local warming. It’s happening. Global warming is a harder thing to experience, but since we are no longer in a Little Ice Age, I’ll accept it. Anthropogenic? So far, the climate models have done little to persuade me.
    The one common factor I have found for all these catastrophes-to-be is the cure. Put the Left in charge, give them money, and do what they say. Shut down our industries, live humbly, and abase ourselves for our sins against Gaia. They said that for the coming Ice Age, for Acid Rain, for Ozone Holes, for Global Warming, and now they are saying Climate Change, because people are starting to snicker behind their hands when they say “warming”.
    It’s politics and religion, it is, and the people working it for everything they can are hucksters and useful idiots.

    • That’s right winters east of the Rockies are getting warmer and the summers are getting cooler. It would appear that the winters are warmer than the summers are cooler – hence the averages are up. Here’s a map of the United States that shows the declining maximum temperature trends:
      The key doesn’t show it, but TMax in most of those states in the Mississippi River valley have shown a negative trend since the 19th century.
      NOAA’s Climate at a Glance

  43. used to be somewhat a lukewarmer but now…don’t even think can be considered that.
    time will tell if I am wrong or not.

  44. AR5 admits a pause. Gavin has a solution for that…3 new GISS versions that turn it into a rise 😉
    While that happens in my face, I’m highly skeptical.

  45. David,
    This and other recent posts (e.g. Larry Kummer) contrast model ensemble projections with global average temperature sets. Most notably, were it not for the recent El Nino, the apparent agreement between the two would not look nearly as good as it does. Yet, whenever we have cold weather, the alarmists are quick to point out that weather is not climate and we should ignore the snow on the ground outside the conference venue. So, the most important take away is that we have to wait at least a couple more years to see if we appear to be at one of the innumerable steps, or if temperatures return to the trend (hiatus) that we appeared to have prior to the most recent El Nino.
    Secondly, as I’ve tried to point out before, averages hide a lot of information, as in, “The Devil is in the details.” If we had a cold equator and hot poles, one could get the same average global temperature. I’ve just finished reviewing the chapter on models (IPCC AR5) and note that the claim for the quality of models has a very high correlation coefficient for GLOBAL average temperatures. However, the correlation coefficients for precipitation patterns only account for less than 72% (CMIP5) of the variance of the spatial patterns. I would then expect that the regional temperatures would be about the same. In summary, it isn’t just important what the projected average global temperatures are, but whether projected regional average temperatures are reliable.

  46. The lukewarmers are total losers.
    They think CO2 controls the climate, which is wrong, but at least they
    usually reject the bogus water vapor tripling the effect of CO2
    positive feedback crackpot global warming theory.
    They are in the middle of the road, and will get run over by traffic on both sides!
    CO2 has never controlled the temperature, and if there is any effect at all,
    it is harmless — most likely too small to notice in a lifetime
    Lukewarmers are not paid to believe CO2 controls the climate.
    That would be a good excuse.
    Lukewarmers generally know enough about science to realize the lack of correlation between
    average temperature and CO2 levels in most decades since 1940.
    Being dumb is not an excuse.
    So if the lukewarmers are not paid to believe, and know enough science not to
    be tricked by climate models that have made wrong predictions for 30 years,
    then what is their problem?
    The problem is they are losers trying to be liked by everyone,
    both global warmunists and skeptics.
    Anyone who thinks the causes of climate change are well known (CO2) is a loser.
    Anyone who thinks computer games can predict the average temperature is a loser.
    Lukewarmers, therefore, are losers.
    They just can’t say “I don’t know” or “No one knows”
    when asked about the future temperature,
    even though both are the correct answers!
    Climate blog for non-scientists

    • Richard Lindzen, Roy Spencer, John Christy, Judith Curry and most other skeptical climate scientists would technically fall into the Lukewarmer category.

      • The fact remains that there is no statistical validation for the Lukewarmer category. I have a great deal of intellectual respect for the names listed but that doesn’t mean that they can statistically prove their assertion about the contribution of CO2 to the observed temperature data. I hold lots of beliefs that I can not prove. It doesn’t make them right or wrong, just unproven.

        • Lindzen, Spencer and Curry have all statistically demonstrated their assertions of climate sensitivities ranging from 0.5 to 1.75 C.

      • @Richard Greene
        Losers with PhDs? A very SPECIAL club I fear. Being wrong in a CLEVER way takes some skill, it’s a sort of Emperor’s Clothes Lite. Still naked but it’s the way you walk that does it.

      • Absence of evidence is not evidence of absence.
        You mis-state the strength of your position.
        Not being able to discern a CO2 signal in the very noisy temperature signal is not evidence that there is no CO2 signal.

    • Richard Greene
      September 25, 2017 at 11:30 am
      The lukewarmers are total losers.
      They think CO2 controls the climate, which is wrong, but at least they
      usually reject the bogus water vapor tripling the effect of CO2
      positive feedback crackpot global warming theory.
      Well I don’t think CO2 controls climate.
      I think the greenhouse effect theory is pseudoscience.
      Mars has 28 times more CO2 per square meter as compared to Earth and
      CO2 of Mars causes no “greenhouse effect” warming- sublimation of
      CO2 at poles- different issue.
      Now Mars has about 25 trillion tonnes of CO2 in it’s atmosphere.
      If 25 trillion tonnes of CO2 or N2 was added to Mars atmosphere, it
      seems there could be some warming.
      Or 50 trillion tonnes of N2 could have less warming effect than
      50 trillion tonnes of 50% mix or 100% CO2.
      Or I think it would have enough of effect that it could be measured.
      I don’t think the effect of CO2 in Earth has been measure but the upper
      limit seems to me, that if CO2 increased from 400 to 800 ppm that this
      might cause 1 C increase to Earth’s average temperature.
      Probably more likely it’s closer to 0.25 C than 1 C
      And if global temperature increase by 2 C before 2100, I think this would
      mostly be good news- but it won’t happen. As there is no reason or evidence
      that it could.

    • “They think CO2 controls the climate”
      When you have to lie about what others are saying, you have lost the argument before it even began.

  47. A trend in climatologically relevant time frames would change my mind.
    A contrived ten year graph, as offered in a recent essay, ain’t even close.
    Floods, storms, droughts, sea level rise…and especially temperatures, rely on massaging numbers to justify the hype.
    Honest numbers…the scariest thing that the climate consensus has.

  48. I do seem to fit the criterion for being a “lukewarmer”. I have commented in other forums that my acceptance of a changing climate and that human activities probably do have an impact even align me with the consensus position of 97% of climate scientists.
    For me to go from a “lukewarmer” to an alarmist, there would need to be observations backing model projections that demonstrated that the current warming trend would continue past the climbing out of the current ice age. Among the items entailed in this would be climate models that could post-dict the cooling from the late1940s to the 1970s, the warming from the late 1970s to the late 1990s, AND the global warming hiatus.

  49. Given: the global temperature is rising.
    I don’t see anything near catastrophe in the historical data on flood/draught, hurricanes, fires, tornadoes, etc, even though the globe has been warming for decades now.
    So what is it exactly is that Lukewarmers have to fear?
    2 degrees warmer, with randomly scattered and time-variable spots around the globe that slightly warmer or slightly cooler? This hypothetical outcome does not motivate me to run out and spend $100 trillion on measures that do little do reduce global warming, while at the same time, sentences the poorest among us to a continued life of subsistence, poor health and misery. Show me the benefit that outweighs those costs.

  50. One thing I don’t see being addressed here is the claim that warming greater than 2°C will be catastrophic. I’m not sure it would be. It seems to me that a little warming has far more benefits yet they are almost never discussed especially by the alarmists and MSM.

    • The biggest scare they have is sea level rise. If the increase in average temperature comes as a result of increasing minimums then storms will not be as strong as they operate of the different temperatures of adjacent air masses. Warmer weather bring more rain so any claims of increasing drought can’t really be true. If there’s more rain then there should be more floods.
      So sea level and flooding are the biggest scares pitted against all of the increases in agricultural productivity and mild weather that comes with more CO2 and a warmer world.

  51. It’s not a piece of information, a chart or data set that will convince people, it’s debate. If the world is going to end from more CO2 in the atmosphere, the climate consensus people should be more than willing to debate competent lukewarmers or skeptics and either win the debate or at least make a very good case for the alarm. “The debate is over” position has done nothing but harm to the consensus position outside of a narrow bubble of people who are already convinced or will benefit from climate policies. Most people see refusal to debate as arrogance or fear of losing on a fair discussion of the issues. Either way, it loses votes.

  52. I take no exception to anyone who believes or rejects the lukewarmist position if they reject the prosposterous green alarmism doing so much damage, but there is a question I’d like to ask the excellent David Middleton and the lukewarmers.
    As we know that for much of Geological history the atmosphere has had between 2,000 to as much as 7,000 ppm CO2 and that temperature at the higher figure seems to have been no more than 4C greater, how does that match the kind of sensitivity postulated by the lukewarmers?
    The Earth has never gone into a true uncontrolled greenhouse , which presumably would be a one-way trip for life. I know the effect of CO2 diminishes as the window it operates in saturates, so do any of the sensitivities suggested by the lukewarmers show a consistency with the relatively small increases to much larger ppm numbers of the Jurassic, etc ?
    Would the answer to this question suggest a validation of the lukewarm position or not ?

    • As we know that for much of Geological history the atmosphere has had between 2,000 to as much as 7,000 ppm CO2 and that temperature at the higher figure seems to have been no more than 4C greater, how does that match the kind of sensitivity postulated by the lukewarmers?

      First… The periods with very high atmospheric CO2 levels were generally warm.
      On a geologic time scale, climate is controlled by First and Second Order processes. These are the big drivers.
      From a human history perspective Third Order processes dominate. Fourth Order processes, which include human contributions, become a factor on the scale of 10’s to 100’s of years.
      Prior to the Quaternary, you really can’t compare past climates to the present because the oceans and continents were configured in a substantially different manner.
      However, all of the evidence indicates that the climate is relatively insensitive to CO2… even if you assume that all of the warming since 1850 was due to an enhanced greenhouse effect (which is an unrealistic assumption).

      • David, I think the above graph showing 1st through 4th order effects is nonsense. Why? For practical purposes, all of the heat content of earth is in the oceans. The oceans heat and cool the atmosphere, not the other way around. Thus, solar induced ocean heat content is a first-order effect. THe 33K attribution to the atmospheric temperature typically given to greenhouse gases is misplaced.

      • Since solar insulation is pretty much constant, the only way to warm or cool the oceans would be to change how easily the oceans transfer their heat to the atmosphere.
        Thus the temperature of the atmosphere strongly influences the temperature of the water.

      • In your first plot, one can see the complete lack of correlation between CO2 and temperature. There are many periods of anti-correlation. That plot runs contrary to the claim that CO2 forces warming.
        You state;

        The periods with very high atmospheric CO2 levels were generally warm

        Your plot does not strongly support that contention. for example:
        (i) in the period 80Mys before present temps were some 8 deg C warmer, yet CO2 was only around 900 to 1200 ppm;
        (ii) In the period 270 My before present temperatures were a little below 9 degC warmer, and CO2 was around 1800 to 400 ppm. The peak temperature coincides with about 400 ppm.
        (iii) In the period 440 Mys before present, temperatures were around – 2 to – 2.8degC and yet CO2 was as high as 4,200 to 4,500 ppm.
        (iv) CO2 was at its highest around 525 Mys before present, but whilst temperatures were warm at around + 3 to 4 degC, this is significantly cooler than the +6, +8 and even +9 degC seen in earlier times when CO2 was lower.
        I agree with the majority of the points you make in your comment, apart from your assessment of what the first plot shows. But of course one must bear in mind your caveat before reading too much into matters 9as well as the general limitation of proxies and the wide error bounds that always accompany proxies):

        Prior to the Quaternary, you really can’t compare past climates to the present because the oceans and continents were configured in a substantially different manner.

        • Prior to the Oligocene, the Earth was much warmer than it is today except for the Pennsylvanian (Upper Carboniferous) ice age, when CO2 was around 400 ppm.
          The only clearly defined high CO2 ice age, during the Ordovician, was significantly warmer than either the Pennsylvanian or Quaternary (present day) ice ages.
          A possible high CO2 ice age occurred during the Late Jurassic to Early Cretaceous. Although the evidence only clearly supports ephemeral glaciation.
          There’s not a strong correlation between CO2 and temperature change over geologic time because plate tectonics and astrophysical forces were also major factors.
          280-400 ppm CO2 yields a minuscule warming effect, relative to other forcing mechanisms.
          280-5,000 ppm is a whole different story.

  53. If ‘Lukewarmism’ is simply defined as pushing the alarmism off beyond one’s lifetime, but still exploiting the issue for funding and political agenda, then no.
    If it is defined as simply acknowledging C02 has some effect – possibly even a non-trivial effect – on the climate, then yes.
    The difference is alarmism and exploitation, and if you’re not standing against these – clearly and publically – then you are part of the problem.

  54. I to have a degree in geology (1968) with some archaeological background also. I know that there were periods in the past with atmospheric CO2 levels many times the current, and the planet’s life thrived. I also recognize that in the more recent past, those CO2 levels fell dangerously close to what some would call extinction levels. All of this has occurred without any help from our species. As a young man during the 70’s glacial scare, I spent quite a bit of time studying the various claims, and at that time thought that maybe man’s transgressions against nature could have some sort of evil effect, but soon got over that.
    Didn’t pay much attention at all to the current warming “threat” until someone posted MM’s hockystick a few years back on a forum I spend some time on with the “look, –we’re all going to die ” hysteria. One look at that graph was all it took for me to know something just didn’t look right, so, in order to refute the claim with some backing, I started looking into what it was all about. That’s when I found WUWT, and discovered just what an educational tool this blog is. I appreciate how even handed the variety of articles posted is, and have come to understand the predictability of the comments.
    The one thing that bothers me is this concept of a “global climate”. I’d always thought of climate being more of a local, or regional thing. After all, the climate of Antarctica is nothing at all like the climate of the midwest US, or the Mediterranean coast, or the Mongolian plateau. And of course, that regional climate does change over time. Personally, I don’t think this heated argument about global warming has anything at all to do with the future of the planet–it’s going to do whatever it wants, irregardless of H.sapiens doings. Seems to me to be a bit arrogant to think so. I’m pretty sure that man can influence the climate through his activities–clear cutting forests for agriculture, creating huge bodies of water by damning river systems, raising local humidity (and allergies) by moving to the desert SW and dragging your well watered and manicured green lawn with you, but that isn’t squat in the grand scheme of things. I look at the burning of fossil fuels as just a stored source of solar energy, and if the resultant CO2 is actually warming the planet a little, so much the better. I was raised in PA, but live in Texas for one reason–shorter milder winter. Cold is not nice.
    I suppose the one thing that would take me from my ho-hum lukewarming perspective towards the climate alarmist side would be the influence on the climate of a whole out nuclear war. But then if that happens nothing much we can do about it except that the earth has survived such catastrophes in the past, and (unless we blow the whole damn rock to bits) will do so again, and again until such time the sun swallows us up. H.sapiens, whither we cause our own or not, will follow every other species into extinction when the time is right.

  55. I find it very interesting that there are several boxes now into which one can put individuals who have different views on the very complicated issue of Climate. Perhaps it would be a good idea to start at the very beginning and consider some of the foundation stones upon which the idea of AGW (or CAGW). I propose we could start sorting peoples opinion out at an early stage by a rigorous application of SCIENCE.
    (Pause for signs of applause or mutterings of “not again”)
    Lets start with some basics. 2 simple science questions:
    1) Can a cool object transfer energy to a warmer object and thus make it hotter via radiation?
    2) Is it correct to add via simple math the radiative fluxes from 2 independent sources and use the resultant sum to determine the temperature of the sink via the SB equation?
    This should be useful as the primary sorting mechanism. Obviously those giving the SCIENTIFICALLY INCORRECT answer can be binned straight away. Clearly the reject bin is going to be pretty huge.
    The interesting spaces to watch will be those where the reject bin is SMALLER than the retained bin.
    Which space does WUWT fall into?

    • Reverend,
      The answer to your first question is that the more agitated atoms in a hot object will transfer some of their kinetic energy to a colder object that is in direct contact. If they are separated by a perfect insulator, no conduction will take place.
      All objects above absolute zero temperature radiate IR EM, which can be thought of as photons, capable of being captured by objects not in direct contact. What is important is the relative intensity and wavelength of the photons/waves emitted by your hot and cold bodies, which contribute to the net gain or loss of energy. However, another consideration is the dispersion of absorption with wavelength. If the cold body is essentially transparent at the wavelengths at which the hot body is transmitting, little to no warming will occur. This is essentially the situation with visible light going through the atmosphere. However, if the cold body is strongly absorbent, its temperature will be increased, which is the case for IR from the Earth being absorbed in the upper atmosphere. Now, for the last situation, which is the essence of your question, the Earth radiates into space, and it cool as it loses photons. However, if the upper atmosphere captures some fraction of the outgoing IR, it will be prevented from leaving the Earth system. Therefore, the Earth will not cool as much as it might have in the absence of the absorber. This should be evident primarily as an increase in temperature of the absorber. That absorber is initially acting as a time delay, with some increase in its total radiation as a result of the T^4 relationship between temperature and radiated energy. So, there will be an increase in the amount of energy radiated to space. At the same time, photons are directed back at the Earth because the atmosphere radiates in all directions. These ‘reflected’ photons are effectively photons that weren’t able to escape ninto space. Most materials on Earth (especially water) absorb IR energy. Therefore they are captured on their ‘return’ trip. The net result is that not all radiated photons are capable of escaping and the fraction increases as the concentration of the absorbers (primarily H2O and CO2) increases. So, it isn’t that a cold object is warming a hot object, it is that a cold object isn’t allowing the hot object to cool as much as it would in the absence of the absorbers.

  56. “So… If you are a fellow Lukewarmer… What evidence would push you toward alarmism? What evidence would push you toward rejecting human impacts on the climate as being less than a rounding error? (Note: I view the impacts as only being slightly larger than a rounding error).”
    Well, first is evidence of how much CO2 warms Earth.
    My assumption is that doubling CO2 will cause less than 1 C of warming.
    BUT I was lukerwarmer when I thought a doubling of CO2 could cause as much as
    3 C of warming. So if a doubling of CO2 causes 2 or 3 C, I will be wrong and very surprised
    and maybe more doubt about being lukewarmer [mainly because I will have been proven wrong and obvious that causes more doubt.
    But since the time I once thought CO2 could cause 3 C of warming [about +20 years ago] I have learned more and become more skeptical. And Climategate certainly had an effect of upon my views of the criminality involved with “global warming”.
    But a basic problem with alarmism is we have a cold ocean, we have warm surface but very cool ocean. Or what is well known is that we are living in an icebox climate- which is average ocean temperature [the entire volume of ocean] is cold plus we have polar ice caps. Or cold ocean and ice caps = icebox climate.
    So simple question is what is needed to make our cold ocean to be warmer.
    So when the oceans get to be near 5 C, I might become alarmed.
    But even if alarmed, the governments are incompetent. They have proven they can’t even reduce CO2 emission and spent trillions of dollars of tax payers money not doing this.
    So being alarmed won’t make join the bandwagon of having a totalitarian governing body- which is the whole purpose of the lefties.
    So for real purpose of global warming, the government would have to prove they much more competent they they have been. Which is probably close to impossible.

  57. I have respect for the so-called Lukewarmers only because they have inoculated their thoughts, like most sentient humans, in the fact that humankind has some intrinsic and superior place in the cosmos . ” Man is all-important”. “Man can control his environment”. Finally, “Man’s emissions can influence the climate”.
    This is the human condition. Lukewarmists have no empirical evidence for their CO2 claims. Indeed, as most admit it is a “belief”. Or , “I think” so and so.
    If there is one area man could change the climate, it would be from the changing the earth’s geography. CO2 has not been proven to do anything except feed our plants.
    I won’t go so far as calling these well-meaning Lukewarmers losers or any other epithet. No more than I would call out someone having a different religion from another’s a loser. It is the human condition.

    • The only thing they have is that CO2 is a GHG in the lab. That’s it.
      From this fact, they conclude, ergo, more of it in the air must cause warming. But it hasn’t been shown to do so, nor is their conclusion inescapable, given how complex is the climate system, with multiple feedback effects. Over much of the planet, water vapor already swamps out CO2’s absorption bands.
      So far, more CO2 has been a good thing, and more is liable to be even better.

      • If it absorbs IR in the lab, it will absorb IR in the wild.
        Physics don’t change based on the location of the molecule.
        Even in the places where there is lots of water vapor, there are still bands for CO2 to absorb, and there are a lot of places where water vapor isn’t close to saturation.

  58. I wouldn’t call the lukewarmer position “illegitimate” – it is not facially absurd, blatant political manipulation like the CACA hysteria – but since not even anthropogenic CO2 increase has been established beyond a reasonable doubt it must at this point be considered probably incorrect.

  59. I said this elsewhere: put those charts with spikes of highs and lows into a more realistic setting. Provide a chart that shows a month-by-month 10 year chart, as well as a chart that shows a month-by-month 100 year time frame, include the same changes in mean temperature on both of them, and you will find that the temperature “spikes” disappear into nearly flat lines.
    I challenge anyone to do this. The real problem is lack of room on a computer screen. Even a 10-year chart like that requires a space nearly the width of a 10×10 foot room.
    If these charts were transferred into a more realistic view, the alarm bells might stop ringing. If they did not stop, there has to be an awfully good reason. If just that 1960 to 2015 chart up above were spread out like that, the compressed spacing disappears into a flat line.

  60. richard verney September 25, 2017 at 12:54 pm
    ‘The signal is completely lost in the noise of natural variability.’
    There. That is truth right there. That the entire cannon of WUWT boffins (and there are many) cannot agree amongst themselves on CO2 sensitivity says to me that the science is so not settled that it’s a joke to claim it is. If any signal cannot be definitively determined (and again, it hasn’t been, see IPCC 3C +/- 1.5C) then it’s game over as far as I’m concerned.
    Activist BS on the other hand is highly detectable.

  61. I’m a “do nothing” luke warmer. In other words, I believe we should do nothing in response to climate change. We don’t need to have regulations to control CO2 output or any other anthropogenic driver. Let technology and the inevitable inflection point in global fecundity take their course. It’s all good. My rationale is the anthropogenic drivers are less than half of the total. Not worth worrying about.

    • I would say, we should do nothing, or at most very little, to try to *prevent* climate change.
      We should do whatever we have to do in *response* to climate change.

      • If we weren’t wasting so much money trying to stop climate change, there’d be a lot left over to mitigate the bad effects of climate change. Assuming we ever find some.

  62. David
    Your view is that

    The AGW hypothesis is that humans are responsible for >50% of the climate change since 1950.

    Whilst, you may well be right, I have so many issues with this view.
    First, I do not consider that there is any evidence that withstands the ordinary rigours of scientific scrutiny that would convinces an objective scientist to accept that there has been any warming post 1940. That does not mean that there has been no warming since then, but simply that there are so many issues with the time series temperature sets that the position is uncertain, and it requires remeasurement.
    In fact, it is quite clear that the warming post 1940 is entirely the artifact of human adjustments made to the data sets. One only has to look at the temperature reconstructions of the 1970s, 1980s, 1990s and today to see that that is the case. Steven G@ddard has a lot on this, so I shall not repeat it. Of course, all the adjustments made to the record could be legitimate and correct, and which case there has been warming, but then again, the adjustments may not be correct and the apparent warming may simply be an artifact of adjustments and biases causes by station drop outs, biasing from rural to urban, biasing towards airport stations, equipment changes etc. such that factually there has been no warming at all,
    Second, if there has been warming, your attribution is simply a guess. It may be a reasonable guess, but a guess it is, nonetheless. Man may be responsible for 10% of the warming, 30%, 50%, 70% or even 100% of the warming. The attribution is simply not known. We cannot say with certainty whether it is zero or 100%. I do not consider that even on the balance of probabilities that a firm % figure can be ascribed. To do so, is nothing more than guesswork, and hence unscientific.
    We do not know whether whatever caused the cooling between 1940 to early 1970s (which in the mid 1970s was thought to be around 0.5 to 0.6 degC of cooling) has continued at the same or even greater rate of cooling through to today, but manmade CO2 emissions gradually increasing from 1950 have first completely offset this cooling and lately more than overcome it producing all of the observed warming. It could be that at the moment there is some natural cycle that is producing a negative forcing of around 0.18 degC per decade cooling but manmade C02 emissions have overcome this and are now producing a warming of around 0.18degC per decade warming. I do not consider that to be the position, but it cannot be ruled out.
    Whilst i would put Climate Sensitivity, if any at all, at no more than 0.8degC per doubling, because of the poor quality of our data sets and the high error margins that they must possess, I do not consider that we can rule out the possibility that Climate Sensitivity is as high as about 4 degC per doubling. In fact, the fact that the IPCC still clings to an upper range of 4.5degc per doubling is an indictment on the poor quality of data available to us, and the wide error bounds that attach to that data.
    But I maintain that on the evidence available to us, we cannot demonstrate that there is any Climate Sensitivity whatsoever to CO2. For that reason, Climate Sensitivity could be zero This ought to be the scientific position, and the IPCC ought to put them lower bound for Climate sensitivity at zero.
    The fact that we have been unable to narrow the bounds of Climate Sensitivity these past 30 or so years, again demonstrates how appallingly inadequate our data sets are.
    I have no problem with lukewarmers who consider that rising levels of CO2 brings more benefit than harm, or that a warmer world will not be catastrophic. Those would appear to be very legitimate and reasonable views to hold. But I do have a problem with lukewarmers who accept in the absence of good quality evidence that CO2 leads to warming since this gives some measure of acceptance and credence to a science which is devoid of scientific rigour and standards, and which is nothing more than a cargo cult.

    • I don’t really disagree with any of this. The radiative forcing effect, sans feedbacks, of a doubling of CO2 works out to around 1 C. All of the evidence points to the feedbacks being somewhere between strongly negative to slightly positive. So… yeah… The sensitivity could very well be zero.

    • It seem to be pretty universal that anyone self selecting as a lukewarmer is a “Why it IS carbon dioxide” believer.
      I would love to find a few lukewarmers who believe CO2 does nada and discuss their alternative theories. Are there any out there?

    • You’re wrong Varny:
      It’s possible the average temperature has not changed since 1940 … or since 1880.
      But it’s likely the average temperature has changed, since our planet is not in thermodynamic equilibrium.
      Given the bias of the people who collect the surface temperature data, I suspect the warming has been overstated … but the surface data are not global, so allow a lot of “infilling” and “adjustments”.
      It’s still possible climate sensitivity to CO2 is ZERO.
      Nothing has happened to the average temperature since 1940 to suggest anything unusual happened to our average temperature (that could not be caused by natural variations of an ever changing climate) … except for warming in the Arctic.

  63. “So… If you are a fellow Lukewarmer… What evidence would push you toward alarmism? What evidence would push you toward rejecting human impacts on the climate as being less than a rounding error? (Note: I view the impacts as only being slightly larger than a rounding error).”
    As one of the first Lukewarmers and the person who popularized and defined the term in a fairly rigorous manner I would say the following.
    I defined Lukewarmer as a position that believes.
    1. C02 is a GHG. Increasing it will warm the planet, not cool it, all other things held equal.
    2. Doubling C02 will cause between 1.5C and 4.5C of warming, all other things held equal.
    3. IF you are offered an over/under bet that ECS = 3C, take the Under bet.
    4. Climate change science suggests we should be concerned ( not alarmed) and
    should look first for no regrets actions we can take.
    Since then folks have bastardized the postion to mean the warming is nothing to be alarmed about,
    or that the warming will be slight etc etc etc.
    comes two questions:
    1. What will make me change being a luke warmer? Well, if more an more evidence shows
    That the OVER BET is more likely, then I would take the over bet. That would mean
    evidence from both paleo and observational estimates of ECS.
    2. What would make me an alarmist? I dont recognize this as an interesting question.
    There’s no reason to being alarmed in any case. One’s concern might increase,
    but there is no reason to be alarmed about the climate problem or the fix. Higher temperatures
    and Higher taxes, both concerning, neither a cause for alarm. Alarm is a reaction to a
    short term threat.

    • 1. C02 is a GHG. Increasing it will warm the planet, not cool it, all other things held equal.
      2. Doubling C02 will cause between 1.5C and 4.5C of warming, all other things held equal.
      3. IF you are offered an over/under bet that ECS = 3C, take the Under bet.
      4. Climate change science suggests we should be concerned ( not alarmed) and
      should look first for no regrets actions we can take.

      1. Agree.
      2. More like 1.0 to 1.5 C.
      3. Agree.
      4. Maybe… At least concerned enough to keep an eye on it.

      • Warming caused by CO2 is unknown.
        Simple lab experiments provide no real data.
        Feedbacks are unknown.
        The warming in the second half on the 20th century blamed on CO2 looks almost exactly like the “natural” warming in the first half of the century.
        There is no evidence to prove whether increasing CO2 has caused ANY warming in the past.
        Therefore any guess of warming caused by CO2 in the future is wild guess.
        But you provided a guess.
        That’s why lukewarmers are losers — they will guess the future average temperature when they do not have sufficient knowledge of climate change to make that guess.
        They do realize the ‘CO2 will cause runaway global warming’ belief is a fantasy, backed by almost no science.
        The obvious “answer” is that today’s scientists do not understand climate change, and do not know the effect of adding CO to the air based on what has happened since 1940.
        Based on the simple laboratory experiments, CO2 rising at 2 ppm a year has been harmless, and is likely to remain harmless in the future.

    • I like rigour. Steven, would you say that “CO2 is a GHG” is a universally applicable property of the gas which will be true everywhere in the universe, for example on other rocky planets with a gaseous atmosphere containing a bit, a fair amount, a lot or even (heaven forbid) almost 100% CO2 concentration?

    • You’re right to take the under, since 3 degrees C per doubling is clearly wrong. No surprise, since it’s without any physical basis and entirely evidence free.
      Average CO2 during the Cretaceous was more than six times its “preindustrial” level, ie some 1700 ppm. The continents were nearing their present positions. Yet mean temperature during that long period was only about four degrees higher. If ECS were as much as three degrees C per doubling, then mean temperature should have been seven or eight degrees hotter, especially since there was so much volcanism and oceans were so much warmer than now.

      • PS: Even “Father of GCMs” Manabe’s 2.0 degrees C per doubling can now be seen to be too high, but a lot more realistic than Hansen’s fantastic WAG of 4.0, also from the 1970s.

    • I like to think that I coined the phrase, “Close only counts in horseshoes and hand grenades.” I never heard anyone else say it before I did.
      I also came up with the idea for satellite navigation in cars… I just didn’t get around to figuring out how to actually implement my idea.

    • It seems like there should be a “5” or even a “6” and “7”.
      5. Natural and living processes thrive on and remove CO2 from the air.
      6. We don’t really understand enough of how all this works together.
      7. So, what should we do to solve a hypothesized Man-made problem?

    • “2. Doubling C02 will cause between 1.5C and 4.5C of warming, all other things held equal.”
      In other words, taking the IPCC position is the lukewarm position?
      Despite all the evidence that has shown conclusively that the IPCCs sensitivity estimates are an order of magnitude too high?

    • David Middleton September 25, 2017 at 3:37 pm
      I like to think that I coined the phrase, “Close only counts in horseshoes and hand grenades.” I never heard anyone else say it before I did.

      Sorry to burst your bubble but Frank Robinson was quoted saying it in Time magazine in July 1973, supposedly also used by Johnnie Carson on the tonight show in the 60s too.

      • I was a Mets fan… So I never listened to anything any Baltimore Oriole ever said… Except for Earl Weaver. And… How do you know Johnny Carson didn’t steal the phrase from me?

    • A key part of the lukewarm view in my mind is the conviction that, at the present time, the cure is in all probability worse than the disease. With that in mind, the one significant change that has any real likelihood of happening before I am not capable of changing my mind any longer would be a significant breakthrough in low/zero carbon energy. If the cost of change becomes minimal (or better yet, profitable) then the case for change becomes overwhelming.
      Of course, part of my lack of concern in the first place is a confidence that if solutions do exist they will ultimately be found. So you could certainly argue that acknowledging that such a solution has been found wouldn’t really be changing my position.

  64. Not sure which group I fit in other than “skeptic”.
    But I do think that the idea of “groups” and the question posed and what would it take to spur one group to “action”, just shows that this is politics and not actual science.
    In this Layman’s opinion, political goals/financial gain is what drives (and funds) the “warmist”, not science.
    As for the rest, well, that’s usually those interested in the science.
    (Sometimes those opposed to the political goals behind the “warmist”.)
    Personally, this Layman has seen nothing but headlines and hype that justifies any political action to limit Man’s CO2 emissions that could prevent CAGW or “Climate Change”.

    • Agree on the “groups” point. It’s arguments between those who believe in different things – “My religion is the RIGHT one because….” What we should be doing is forcing the CAGW/AGW crowd to test all their beliefs against proper science. It’s is highly distracting and wasting energy to have to also force “lukewarmers” to do the same. I might have a huge success and even manage to convince Roy “I have an experiment” Spencer that most of his “proofs” are bunkum but that gets us nowhere in reversing this AGW madness.
      It’s like I need 2 armies now. one to fight AGW and one to fight Lukies. Now I know why John (Qualified Cartoonist and Na2i costume tester) has to be so proactive with respect to censorship. He needs to just fight on ONE front.

  65. If, as seems likely from the empirical data, equilibrium climate sensitivity (ECS) is below 1 C/doubling then global warming is harmless.
    That is easy to demonstrate, since an increase in 1 C would require 400 ppmV more CO2 to be added to the atmosphere and 1 C more would require another 800 ppmV to be added. Thus a 2 C rise would require 1,200 ppmV more CO2 than today.
    Since the last ice age pCO2 has risen about 120 ppmV. So to get 2 C more out of CO2 we’d have to add another ten times as much as we have emitted in all our recorded history.
    The same people used to be hysterical about peak oil, which was supposed to happen by 1990 or 2000 or 2010 or whenever. If peak oil is supposed to be happening now how exactly are humans going to find ten times as much carbon to burn?
    And that only increases temperature by a mostly harmless 2 C if ECS is 1 C/doubling. Which is a big if (my estimate using HadCET is less than 0.7 C/doubling).
    That is what “luke warmism” means: CO2 is harmless, get on with your lives and stop destroying civilization with your stupid green religion.

    • Yes but it’s even better than that, if ECS is zero or negative we can burn as much fossil fuel as we like with impunity. All of it. As fast as we like.
      Of course we can do it sensibly, taking account of pollution by careful design of the systems. I guesstimate we probably have 200 – 500 years worth of fossil fuel left which should be plenty of time to get something else going (salt reactors?) for when it does run out/become too expensive to extract.
      This scenario looks like fantastic news for the planet. No worries, cheap energy and as a bonus a huge number of lefties will have their brains explode (judging by the response I receive when I spell out this Good News scenario!).

      • Even if ECS is as high as 1.0C, we could still burn as much as we want without bad consequences.
        The small amount of warming being created would be entirely beneficial.
        Even higher ECS’s such as 2 or 3C wouldn’t be a problem because in reality we can’t burn as much as we want, since it is a limited resource. We would run out of fossil fuels long before temperature increases started going past the beneficial levels.

  66. A commonsense view would be something like this. Lot’s of people in science are getting in a flurry about the effects of CO2 emissions, lot’s of others are saying it’s all bollocks. But most are saying the earth is getting warmer and man-made emissions are having some effect even if we don’t agree what it is or on what the actual mechanisms are, and most also agree we don’t have enough good quality data anyway so we cannot model it well enough to predict with confidence the effects of changing man-made influences. Neither can we even predict with certainty the damaging effects and beneficial effects of a change in temperatures that is consistent with empirical data. So how about we spend a moderate amount of money, not on enabling one side of the debate but on a) improving the quality of data available to all sides of the debate; b) researching further the areas of greatest uncertainty, c) developing alternatives to fossil fuel energy sources on a moderate scale without harm to economies and without overlays of Socialist desires to impoverish rich countries by transferring their wealth to the third world, and d) waiting to see what occurs over a reasonably well known natural cycle of periodicity (22, 60?) years having set up intensive monitoring in critical locations and of critical factors for this purpose.
    It’s affordable, it removes the uncertainty. But it will take time because the natural cycles are long. So it will annoy the people impatient to be proven right within the short timeframes of their career progressions. Good because that will reduce heir ability to manipulate politics and economics, which being climate scientists they know little about.
    And if world temperatures suddenly shoot up proving CAGW, we will have much greater ability to deal with it since we won’t have wasted trillions barking up the wrong tree and impeding economic development, health in developing countries etc and we will have greatly improved the science base with better data.

    • A quibble.
      “And if world temperatures suddenly shoot up proving CAGW,..”
      That wouldn’t prove anything as to the cause, Man or nature or, if both, to what degree of either.

      • Yes but it would mean that the initial assumption of ‘don’t panic until I get there’ was a bit hasty. So regardless of cause something needing money would need to be done assuming this sudden rise on temperature had visible impacts, even if it s only to move people to dry land! And the better science base would enable your questions to be answered better than they can be today.

    • Replying to myself: it was partly tongue in cheek but there is a serious question here. What would be the areas climate research money should be spent on in order to improve data quality and reducing the greatest uncertainties? Suggestions please. imagine you are now in charge of the climate research budget of the world. What would you spend the money on?

    • Or spend a much smaller amount of money testing the theories relating to the “It’s NOT carbon dioxide” view. IF we can show scientifically and robustly that the AGW theories are completely wrong, and if we can show that the atmosphere does not work anything like we think we can leap into the new paradigm rapidly.
      Now I know many of you think this is JUNK. So what. TEST IT. A proper bit of scientific research into the gravito-thermal effect. If you are right and it is indeed all BOLLOCKS then we can move on, cross it off the list, put it in the dusbin.
      We can probably do a 10m vertical column of argon set of experiments for the low £millions. A trivial drop in the ocean of world expenditure on CO2 mitigation. Irrespective of the result, positive or negative, I think it will be money well spent to finally, after all these years, properly test the ideas of Loschmidt.

  67. I am still waiting for some clear scientific proof that the relatively tiny emissions of CO2 by human activity, compared to natures giant resources, has any detectable effect on the World’s Climate. There may be more CO2 around, but where is it coming from and what exactly is it doing except make plants happy?

  68. “So then because thou art lukewarm, and neither cold nor hot, I will spue thee out of my mouth.”
    Revelation 3:16 KJV

  69. “What evidence would push you toward rejecting human impacts on the climate as being less than a rounding error?”
    A negative water vapour feedback.

  70. ntesdorf: Yes. How likely is it that our total historical industrial output at 1% of the carbon cycle dominates it? Our annual output is lost in the data noise. The Antarctic ocean sink is the most significant unknown.
    My main point is that the greenhouse effect (atmosphere T – no atmosphere T = 33 C) is an assumption that’s never been quantified by warmists, or if it has they’ve kept quiet about it.
    They talk about spectral transmission of the atmosphere ignoring the accepted fact that IR transfers energy from surface to space even when it is absorbed. The key question being ignored is how fast is it transferred – the radiative delay.
    My calculation is typically about 4 hours, which seems like a long time, but it doesn’t do much heating. The intuitive comparison is a 200W lightbulb heating a gym for 4 hours. I ignore convective and evaporative transfer which speed things up greatly.
    Answer: ∆T = about 0.15 C, not 33 C.
    The calculations (in my Radiative Delay article) are fairly simple. I’ve provided a spreadsheet. My challenge to warmists – luke or otherwise – is to show me where I’m significantly wrong. It’s a first order estimate to keep the physics simple, but I doubt that I’m out by a factor of 200.

    • Simple physics indeed are the key to beginning to understand this. Start from 2 identical rocky planets the same distance from the sun. One has the earth’s atmosphere, the other has none. This may look like a difficult thought experiment, it’s tricky to do the real experiment as the Magrethian stores are not open this millenium (some kind of religious holiday for mice IIRC). So we have to do it in our heads…. OH NO WE DON’T !!!!! We have exactly the right “apparatus” already. It is called the moon.
      Consider carefully the difference between the plot of moon surface regolith temperature over moon day/night versus earth surface temperature over earth day/night. One rotation on axis is enough to extract some basic physics. Clearly a gaseous atmosphere has a MODERATING effect on surface temperature. It is cooler in the day and hotter at night. Forget averages for the moment. We know what the waveform of the energy input is for any particular sq m. Compare the graphs between earth and moon and explain using simple physics how a gaseous atmosphere has a moderating effect on the surface temperature of a rock.
      How exactly does the gas in the way make the rock cooler when exposed to the full sunlight? How exactly does the gas in the way make the formerly daytime heated rock lose less heat at night time? It’s sort of like it SLOWS DOWN the heat loss. Remember those graphs, X axis is TIME, very instructive to look at the slopes.
      Planets which rotate relative slowly compared to the earth are quite interesting.

      • A large dense atmosphere (whatever its composition) has a large thermal mass and large thermal inertia.
        But this is particularly so when one is dealing with a water world where there are phase changes to water. It is a matter of enthalpy.

      • “How exactly does the gas in the way make the rock cooler when exposed to the full sunlight?”
        Absorption of solar near infrared by atmospheric water vapour, and some minor scattering.

      • As rv says, atmosphere acts as a buffer – cooler than surface during the day and warmer at night.
        Transfer in most (moist) places mainly radiative via water vapour. Some thermal conductivity and evaporation.
        Because surface radiation increases with T^4, daytime cooling reduces radiation more than nighttime warming increases it. So mean temperature increases to regain radiative balance over the daily cycle.

    • “My main point is that the greenhouse effect (atmosphere T – no atmosphere T = 33 C) is an assumption that’s never been quantified by warmists”
      greenhouse effect is a known misnomer, and the major issue is that it hides the difference between the effect of atmosphere, even without GHG, and the effetcts of GHG.
      As The Reverend Badger pointed out, even without any GHE, atmosphere rises average temperature (because of T^4 law, lowering maximum temp lowers radiative loss much more than rising minimal temperature increase it).

  71. Manmade warming was merely a plausible hypothesis that the data disproved with hiatus’ in the Argo sea surface temps, cooling of the stratosphere and warming of the troposphere whilst CO2 was still rising. This meant that nobody could separate out natural from manmade warming. All we actually knew was that the previous alarmism was unfounded, that models were inadequate for policy and that skepticism was proven to be the wiser outlook. Struck by the real world data disproving their apocalyptic scenarios some alarmists then decided to adjust the data instead of their opinion. This is the dogmatic bias that needs addressed! Believe what you like but don’t call that belief a science!

    • All correct… except for the bit about disproving their stated hypothesis.
      While there is no evidence supporting catastrophic AGW… As nearly as I can tell, *their* hypothesis is that anthropogenic GHG emissions are the cause of >50% of the warming since 1950. I don’t see how that hypothesis can be proven or disproven. However, there is at least some evidence that anthropogenic GHG emissions are the cause some of the warming since 1950. Although it is not quantifiable without either a firm grasp of climate sensitivity or the 100% natural contribution.

      • GHG emissions are the cause of >50% of the warming since 1950. I don’t see how that hypothesis can be proven or disproven.
        It will be disproven in time.
        Or it was thought CO2 caused warming before 1950.
        In a few years, are going to say it stated when China become the largest emitter of CO2?
        Or China is currently more than twice US, and US was thought to be part of the major cause of global warming. And seems US will continue to lower it’s emiisions and China will continue to cause more [though China may not report it].

  72. “Lukewarmer” is just a stupid label. A position can only be described as scientific or unscientific or outside the realm of science. The position that observed global warming is mostly man-made is unscientific. To be scientific, “mostly” must be quantified precisely (51-100% is no good) and must be a result of rigorous statistical analysis of legitimate (not tampered) temperature data that rejects the null hypothesis (natural causes) A “100% consensus” is outside the realm of science. It is not even wrong. Climate models are math not science. Even if all the equations are correct, they don’t prove AGW. They only prove the math is correct. Mathematicians can prove the equations of ten-dimensional space, it doesn’t prove they exist. Science requires empirical evidence not just fantastic number crunching.

    • Climate model aren’t math either. Chaos theory IS math, and its math forbids to use Taylor’s theorem in chaotic systems, while this is just what climate models are doing. Math tells that if you try nonetheless, you’ll just get the kind of random BS that climate model provides, as they do.
      Math tells that climate model are just useless BS.

    • Labeling a certain set of beliefs as lukewarmer is no more nonsensical than is labeling a certain physics theory as String theory.
      It’s just a label that’s applied to a certain position.

  73. Longer term geological evidence and the faint sun paradox essentially can rule out high climate sensitivity over the long term. We know that liquid oceans have been present on Earth as early as 4 billion years ago, when the sun was 30% less bright. This means temperatures cannot have been vastly different than today. As the sun strengthened feedbacks as high as 2 watts/m2/degC would have caused run away temperatures, and boiled the oceans. It seems likely that there are stabilizing effects on climate which lead a water covered planet like Earth to self-regulate temperatures
    As a lukewarmer, here’s what it would take to make ME concerned about global warming:
    1. Verification that the Stefan-Boltzmann law is wrong, and temperature increases at a much greater rate than the fourth ROOT of the radiation flux.
    2. A drastic revision of Astrophysical theory, demonstrating that stars do NOT become more luminous as they age.
    3. A drastic revision from geologists demonstrating that the earth and sun are NOT about 4.6 billion years old, and that the earth did NOT have liquid oceans and life going back about 4 billion years.
    The possibility of all three of these happening is damn close to zero.

    • To add to your mysteries:
      How did Mars have liquid oceans, some 3.5 to 4 billion years ago, as some claim, if the sun was weak at that time?

    • Most people think of the Carboniferous as a hot, swampy forest with lots of ferns and big bugs. In the US, the Carboniferous is subdivided into the Mississippian (360-320 MYA) and the Pennsylvanian (320-300 MYA). The Mississippian was hot with a high CO2 concentration, the subsequent Pennsylvanian climate was very similar to that of today… relatively cool temperatures and about 400 ppm CO2.

  74. Re Climate sensitivity see
    It says:
    “The IPCC AR4 SPM report section 8.6 deals with forcing, feedbacks and climate sensitivity. It recognizes the shortcomings of the models. Section 8.6.4 concludes in paragraph 4 (4): “Moreover it is not yet clear which tests are critical for constraining the future projections, consequently a set of model metrics that might be used to narrow the range of plausible climate change feedbacks and climate sensitivity has yet to be developed”
    What could be clearer? The IPCC itself said in 2007 that it doesn’t even know what metrics to put into the models to test their reliability. That is, it doesn’t know what future temperatures will be and therefore can’t calculate the climate sensitivity to CO2. This also begs a further question of what erroneous assumptions (e.g., that CO2 is the main climate driver) went into the “plausible” models to be tested any way.
    The IPCC itself has now recognized this uncertainty in estimating CS – the AR5 SPM says in Footnote 16 page 16 (5): “No best estimate for equilibrium climate sensitivity can now be given because of a lack of agreement on values across assessed lines of evidence and studies.” Paradoxically the claim is still made that the UNFCCC Agenda 21 actions can dial up a desired temperature by controlling CO2 levels. This is cognitive dissonance so extreme as to be irrational. There is no empirical evidence which requires that anthropogenic CO2 has any significant effect on global temperatures.
    The climate model forecasts, on which the entire Catastrophic Anthropogenic Global Warming meme rests, are structured with no regard to the natural 60+/- year and, more importantly, 1,000 year periodicities that are so obvious in the temperature record. The modelers approach is simply a scientific disaster and lacks even average commonsense. It is exactly like taking the temperature trend from, say, February to July and projecting it ahead linearly for 20 years beyond an inversion point. The models are generally back-tuned for less than 150 years when the relevant time scale is millennial. The radiative forcings shown in Fig. 1 reflect the past assumptions. The IPCC future temperature projections depend in addition on the Representative Concentration Pathways (RCPs) chosen for analysis. The RCPs depend on highly speculative scenarios, principally population and energy source and price forecasts, dreamt up by sundry sources. The cost/benefit analysis of actions taken to limit CO2 levels depends on the discount rate used and allowances made, if any, for the positive future positive economic effects of CO2 production on agriculture and of fossil fuel based energy production. The structural uncertainties inherent in this phase of the temperature projections are clearly so large, especially when added to the uncertainties of the science already discussed, that the outcomes provide no basis for action or even rational discussion by government policymakers. The IPCC range of ECS estimates reflects merely the predilections of the modellers – a classic case of “Weapons of Math Destruction” (6).

  75. I utterly reject the idea that we are involved in a great big misunderstanding, and it amazes me that so many otherwise intelligent people still believe we are . . It’s like a gang of robbers are holding up a bank, and some other customers are discussing what it is about doing business at a bank, these fellows don’t understand . .

    • Several trillion dollars of public funds have been squandered on global warming hysteria. There never was any evidence that climate sensitivity to increasing CO2 was high enough to cause dangerous global warming. Claims of wilder weather, etc. are pure fiction. Global warming alarmism is a failed hypothesis.
      Since 1940 there has been ~22 years of positive correlation of temperature with CO2, and ~55 years of negative or ~zero correlation. The global warming hypo is contradicted by a full-Earth-scale test since 1940, when fossil fuel combustion accelerated. CO2 is NOT a significant driver of global warming.
      The leading advocates of global warming hysteria and their institutions have profited handsomely from this obvious sc@m. What will dissuade them are huge lawsuits under civil RICO in the USA, and class action lawsuits elsewhere.

      • MACCRAY
        Your post is a brilliant summary of the climate change scam that took you only three short, well written paragraphs.
        But what we really want you to discuss is whether +2.0 degrees will really cause a climate disaster, or whether +2.0 degrees is perfectly safe, but +2.1 degrees will cause a disaster?
        Also, we need to know how high the hills must be when we move up to the hiils to avoid the global warming flooding in the valleys where we now live?
        Seriously now, I’m not sure if the CO2 correlation with average temperature should look at individual years.
        I don’t trust the temperature data to be that accurate from year to year, so I look only at broad trends, and sI tart using satellite data as soon as it became available.
        My own “correlation summary” is below:
        Since 1940 there have been three different relationships of CO2 levels and average temperature:
        1940 to 1975 Negative correlation
        1975 to 2003 Positive correlation
        2003 to 2015 Little or no correlation
        My Conclusion:
        Three different CO2 – average temperature relationships in just 75 years is strong evidence that CO2 levels do not control the average temperature of our planet.

      • Richard Greene wrote:
        Since 1940 there have been three different relationships of CO2 levels and average temperature:
        1940 to 1975 Negative correlation
        1975 to 2003 Positive correlation
        2003 to 2015 Little or no correlation””
        Richard, your summary and mine are close – I say no significant warming since ~1997, you say since 2003. Close enough.
        IN answer to your question (I hope):
        IF climate is sensitive to increasing atmospheric CO2, that sensitivity is quite low, less than 1C/(2xCO2) and it is unlikely that CO2-induced warming will exceed 1C, and highly unlikely it will reach 2C.
        As we published in 2002::
        “Climate science does not support the theory of catastrophic human-made global warming – the alleged warming crisis does not exist.”
        Then there is the wild card:
        I am still awaiting an intelligent response to my 2008 observation that atmospheric CO2 LAGS temperature by ~9 months in the modern data record. The best response to date is “It MUST BE a feedback effect”. Right-o, and if frogs could fly they wouldn’t have to bump around on their butts. 🙂
        Best regards, Allan

  76. CO2 absorbs IR from the ground and thermalizes it within a few feet of the ground.
    I use a figure of 50m for IR mean free path at ground level, though I’ve seen a wide range of values suggested.
    At TOA, CO2 absorbs and re-radiates IR, making an opaque layer to 15-micron IR,
    Radiative gasses are largely excited and de-excited in collisions – mainly with N2 and O2. Opacity implies a passive absorber. Air with RGs is active and bathed in a photon sea of its own creation.
    Central to the whole AGW issue is how fast this radiation transfers heat from the Earth’s surface to space. That’s the radiative delay I mentioned above. It varies with wavelength. I start with a mean value measured as downwelling at the surface.

  77. Excerpting my post from above, for Rev. Badger and others:
    When the climate science community ignores credible evidence such as this, is it because they think it is irrelevant or because it makes their heads hurt to think outside their comfort zones?
    Regards, Allan 🙂
    I proved in January 2008 (published on icecap.us) that CO2 lags temperature at all measured time scales, from ~~300 to 800 years in the ice core record to ~9 months in the modern data record, on a shorter time cycle. The proof is that dCO2/dt changes ~contemporaneously with global temperature, and its integral atmospheric CO2 lags temperature by about 9 months. Here is an approximation: http://www.woodfortrees.org/plot/esrl-co2/from:1979/mean:12/derivative/plot/uah5/from:1979/scale:0.22/offset:0.14
    If ECS was significant, CO2 would not lag temperature at all measured time scales and this close relationship would not be apparent in the data record.
    My conclusion does NOT mean that current temperature change is the only or even the primary driver of increasing CO2 – other major drivers of increasing CO2 could include fossil fuel combustion, deforestation, deep ocean exsolution of CO2, etc.
    Humlum et al published a conclusion similar to mine in 2013, but the climate science community is only now starting to openly discuss this subject – I think it is important, far too important to be ignored.

  78. https://wattsupwiththat.com/2017/07/20/alarums-and-excursions/comment-page-1/#comment-2559727
    RE a successful predictive track record. We published the following in 2002*.
    “The ultimate agenda of pro-Kyoto advocates is to eliminate fossil fuels, but this would result in a catastrophic shortfall in global energy supply – the wasteful, inefficient energy solutions proposed by Kyoto advocates simply cannot replace fossil fuels.”
    We also wrote in the same article, prior to recognition that the current ~20 year “Pause” was already underway:
    “Climate science does not support the theory of catastrophic human-made global warming – the alleged warming crisis does not exist.”
    Regards to all, Allan
    * Source:
    PEGG, reprinted in edited form at their request by several other professional journals , The Globe and Mail and La Presse in translation, by Baliunas, Patterson and MacRae.

  79. I do consider myself a “lukewarmer”. What would push me towards more alarm is I’m seeing the possibility of a “step factor” in how the temps are moving that creates end point problems in averaging and leads to inadvertent cherry picking when you look at 10 or 20 year trends. So I want to see what temps do over the next couple years post the big 2016 spike. Looking at UAH, do they stay around that .4C area or come down a bit, even if higher than the previous .2C run we had there? So far we haven’t seen anything close to the falloff in temps we saw after ’98, but it’s still a bit early to say as well.

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