The Skeptics Case

Who Are You Going To Believe – The Government Climate Scientists or The Data?

By Dr David M.W. Evans (republished here with permission, PDF link below)

We check the main predictions of the climate models against the best and latest data. Fortunately the climate models got all their major predictions wrong. Why? Every serious skeptical scientist has been consistently saying essentially the same thing for over 20 years, yet most people have never heard the message – here it is, put simply enough for any lay reader willing to pay attention.

What the Government Climate Scientists Say

Figure 1: The climate models. If the CO2 level doubles (as it is on course to do by about 2070 to 2100), the climate models estimate the temperature increase due to that extra CO2 will be about 1.1°C × 3 = 3.3°C.i

The direct effect of CO2 is well-established physics, based on laboratory results, and known for over a century.ii

Feedbacks are due to the ways the Earth reacts to the direct warming effect of the CO2. The threefold amplification by feedbacks is based on the assumption, or guess, made around 1980, that more warming due to CO2 will cause more evaporation from the oceans and that this extra water vapor will in turn lead to even more heat trapping because water vapor is the main greenhouse gas. And extra heat will cause even more evaporation, and so on. This amplification is built into all the climate models.iii The amount of amplification is estimated by assuming that nearly all the industrial-age warming is due to our CO2.

The government climate scientists and the media often tell us about the direct effect of the CO2, but rarely admit that two thirds of their projected temperature increases are due to amplification by feedbacks.

What the Skeptics Say 

image

Figure 2: The skeptic’s view. If the CO2 level doubles, skeptics estimates that the temperature increase due to that extra CO2 will be about 1.1°C × 0.5 ≈ 0.6°C.iv

The serious skeptical scientists have always agreed with the government climate scientists about the direct effect of CO2. The argument is entirely about the feedbacks.

The feedbacks dampen or reduce the direct effect of the extra CO2, cutting it roughly in half.v The main feedbacks involve evaporation, water vapor, and clouds. In particular, water vapor condenses into clouds, so extra water vapor due to the direct warming effect of extra CO2 will cause extra clouds, which reflect sunlight back out to space and cool the earth, thereby reducing the overall warming.

There are literally thousands of feedbacks, each of which either reinforces or opposes the direct warming effect of the extra CO2. Almost every long-lived system is governed by net feedback that dampens its response to a perturbation. If a system instead reacts to a perturbation by amplifying it, the system is likely to reach a tipping point and become unstable (like the electronic squeal that erupts when a microphone gets too close to its speakers). The earth’s climate is long-lived and stable— it has never gone into runaway greenhouse, unlike Venus — which strongly suggests that the feedbacks dampen temperature perturbations such as that from extra CO2.

What the Data Says

The climate models have been essentially the same for 30 years now, maintaining roughly the same sensitivity to extra CO2even while they got more detailed with more computer power.

  • How well have the climate models predicted the temperature?
  • Does the data better support the climate models or the skeptic’s view?

Air Temperatures

One of the earliest and most important predictions was presented to the US Congress in 1988 by Dr James Hansen, the “father of global warming”:

image

Figure 3: Hansen’s predictionsvi to the US Congress in 1988, compared to the subsequent temperatures as measured by NASA satellitesvii.

Hansen’s climate model clearly exaggerated future temperature rises.

In particular, his climate model predicted that if human CO2 emissions were cut back drastically starting in 1988, such that by year 2000 the CO2 level was not rising at all, we would get his scenario C. But in reality the temperature did not even rise this much, even though our CO2 emissions strongly increased – which suggests that the climate models greatly overestimate the effect of CO2 emissions.

A more considered prediction by the climate models was made in 1990 in the IPCC’s First Assessment Report:viii

image

Figure 4: Predictions of the IPCC’s First Assessment Report in 1990, compared to the subsequent temperatures as measured by NASA satellites.

It’s 20 years now, and the average rate of increase in reality is below the lowest trend in the range predicted by the IPCC.

Ocean Temperatures

The oceans hold the vast bulk of the heat in the climate system. We’ve only been measuring ocean temperature properly since mid-2003, when the Argo system became operational.ix,x In Argo, a buoy duck dives down to a depth of 2,000 meters, measures temperatures as it very slowly ascends, then radios the results back to headquarters via satellite. Over three thousand Argo buoys constantly patrol all the oceans of the world.

image

Figure 5: Climate model predictionsxi of ocean temperature, versus the measurements by Argoxii. The unit of the vertical axis is 1022 Joules (about 0.01°C).

The ocean temperature has been basically flat since we started measuring it properly, and not warming as quickly as the climate models predict.

Atmospheric Hotspot

The climate models predict a particular pattern of atmospheric warming during periods of global warming; the most prominent change they predict is a warming in the tropics about 10 km up, the “hotspot”.

The hotspot is the sign of the amplification in their theory (see Figure 1). The theory says the hotspot is caused by extra evaporation, and by extra water vapor pushing the warmer wetter lower troposphere up into volume previously occupied by cool dry air. The presence of a hotspot would indicate amplification is occurring, and vice versa.

We have been measuring atmospheric temperatures with weather balloons since the 1960s. Millions of weather balloons have built up a good picture of atmospheric temperatures over the last few decades, including the warming period from the late 70’s to the late 90’s. This important and pivotal data was not released publicly by the climate establishment until 2006, and then in an obscure place.xiii Here it is:

image

Figure 6: On the left is the data collected by millions of weather balloons.xiv On the right is what the climate models say was happening.xv The theory (as per the climate models) is incompatible with the observations. In both diagrams the horizontal axis shows latitude, and the right vertical axis shows height in kilometers.

In reality there was no hotspot, not even a small one. So in reality there is no amplification – the amplification shown in Figure 1 does not exist.xvi

Outgoing Radiation

The climate models predict that when the surface of the earth warms, less heat is radiated from the earth into space (on a weekly or monthly time scale). This is because, according to the theory, the warmer surface causes more evaporation and thus there is more heat-trapping water vapor. This is the heat-trapping mechanism that is responsible for the assumed amplification in Figure 1.

Satellites have been measuring the radiation emitted from the earth for the last two decades. A major study has linked the changes in temperature on the earth’s surface with the changes in the outgoing radiation. Here are the results:

image

Figure 7: Outgoing radiation from earth (vertical axis) against sea surface temperature (horizontal), as measured by the ERBE satellites (upper left graph) and as “predicted” by 11 climate models (the other graphs).xvii Notice that the slope of the graphs for the climate models are opposite to the slope of the graph for the observed data.

This shows that in reality the earth gives off more heat when its surface is warmer. This is the opposite of what the climate models predict. This shows that the climate models trap heat too aggressively, and that their assumed amplification shown in Figure 1 does not exist.

Conclusions

All the data here is impeccably sourced—satellites, Argo, and weather balloons.xviii

The air and ocean temperature data shows that the climate models overestimate temperature rises. The climate establishment suggest that cooling due to undetected aerosols might be responsible for the failure of the models to date, but this excuse is wearing thin—it continues not to warm as much as they said it would, or in the way they said it would. On the other hand, the rise in air temperature has been greater than the skeptics say could be due to CO2. The skeptic’s excuse is that the rise is mainly due to other forces – and they point out that the world has been in a fairly steady warming trend of 0.5°C per century since 1680 (with alternating ~30 year periods of warming and mild cooling) where as the vast bulk of all human CO2 emissions have been after 1945.

We’ve checked all the main predictions of the climate models against the best data:

image

The climate models get them all wrong. The missing hotspot and outgoing radiation data both, independently, prove that the amplification in the climate models is not present. Without the amplification, the climate model temperature predictions would be cut by at least two thirds, which would explain why they overestimated the recent air and ocean temperature increases.

Therefore:

  1. The climate models are fundamentally flawed. Their assumed threefold amplification by feedbacks does not in fact exist.
  2. The climate models overestimate temperature rises due to CO2 by at least a factor of three.

The skeptical view is compatible with the data.

Some Political Points

The data presented here is impeccably sourced, very relevant, publicly available, and from our best instruments. Yet it never appears in the mainstream media – have you ever seen anything like any of the figures here in the mainstream media? That alone tells you that the “debate” is about politics and power, and not about science or truth.

This is an unusual political issue, because there is a right and a wrong answer and everyone will know which it is eventually. People are going ahead and emitting CO2 anyway, so we are doing the experiment: either the world heats up by several degrees by 2050, or it doesn’t.

Notice that the skeptics agree with the government climate scientists about the direct effect of CO2; they just disagree just about the feedbacks. The climate debate is all about the feedbacks; everything else is merely a sideshow. Yet hardly anyone knows that. The government climate scientists and the mainstream media have framed the debate in terms of the direct effect of CO2 and sideshows such as arctic ice, bad weather, or psychology. They almost never mention the feedbacks. Why is that? Who has the power to make that happen?

About the Author

Dr David M.W. Evans consulted full-time for the Australian Greenhouse Office (now the Department of Climate Change) from 1999 to 2005, and part-time 2008 to 2010, modeling Australia’s carbon in plants, debris, mulch, soils, and forestry and agricultural products. Evans is a mathematician and engineer, with six university degrees including a PhD from Stanford University in electrical engineering. The area of human endeavor with the most experience and sophistication in dealing with feedbacks and analyzing complex systems is electrical engineering, and the most crucial and disputed aspects of understanding the climate system are the feedbacks. The evidence supporting the idea that CO2 emissions were the main cause of global warming reversed itself from 1998 to 2006, causing Evans to move from being a warmist to a skeptic.

Inquiries to david.evans@sciencespeak.com.

Republished on www.wattsupwiththat.com

This document is also available as a PDF file here: TheSkepticsCase

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References

i More generally, if the CO2 level is x (in parts per million) then the climate models estimate the temperature increase due to the extra CO2 over the pre-industrial level of 280 ppm as 4.33 ln(x / 280). For example, this model attributes a temperature rise of 4.33 ln(392/280) = 1.46°C to the increase from pre-industrial to the current CO2 level of 392 ppm.

ii The direct effect of CO2 is the same for each doubling of the CO2 level (that is, logarithmic). Calculations of the increased surface temperature due to of a doubling of the CO2 level vary from 1.0°C to 1.2°C. In this document we use the midpoint value 1.1°C; which value you use does not affect the arguments made here.

iii The IPCC, in their last Assessment Report in 2007, project a temperature increase for a doubling of CO2 (called the climate sensitivity) in the range 2.0°C to 4.5°C. The central point of their model estimates is 3.3°C, which is 3.0 times the direct CO2 effect of 1.1°C, so we simply say their amplification is threefold. To be more precise, each climate model has a slightly different effective amplification, but they are generally around 3.0.

iv More generally, if the CO2 level is x (in parts per million) then skeptics estimate the temperature increase due to the extra CO2 over the pre-industrial level of 280 ppm as 0.72 ln(x / 280). For example, skeptics attribute a temperature rise of 0.72 ln(392/280) = 0.24°C to the increase from pre-industrial to the current CO2 level of 392 ppm.

v The effect of feedbacks is hard to pin down with empirical evidence because there are more forces affecting the temperature than just changes in CO2 level, but seems to be multiplication by something between 0.25 and 0.9. We have used 0.5 here for simplicity.

vi Hansen’s predictions were made in Hansen et al, Journal of Geophysical Research, Vol 93 No D8 (20 Aug 1988) Fig 3a Page 9347: pubs.giss.nasa.gov/docs/1988/1988_Hansen_etal.pdf. In the graph here, Hansen’s three scenarios are graphed to start from the same point in mid-1987 – we are only interested in changes (anomalies).

vii The earth’s temperature shown here is as measured by the NASA satellites that have been measuring the earth’s temperature since 1979, managed at the University of Alabama Hunstville (UAH). Satellites measure the temperature 24/7 over broad swathes of land and ocean, across the whole world except the poles. While satellites had some initial calibration problems, those have long since been fully fixed to everyone’s satisfaction. Satellites are mankind’s most reliable, extensive, and unbiased method for measuring the earth’s air temperature temperatures since 1979. This is an impeccable source of data, and you can download the data yourself from vortex.nsstc.uah.edu/data/msu/t2lt/uahncdc.lt (save it as .txt file then open it in Microsoft Excel; the numbers in the “Globe” column are the changes in MSU Global Monthly Mean Lower Troposphere Temperatures in °C).

viii IPCC First Assessment Report, 1990, page xxii (www.ipcc.ch/ipccreports/far/wg_I/ipcc_far_wg_I_full_report.pdf) in the Policymakers Summary, Figure 8 and surrounding text, for the business-as-usual scenario (which is what in fact occurred, there being no significant controls or decrease in the rate of increase of emissions to date). “Under the IPCC Business-as-Usual (Scenario A) emissions of greenhouse gases, the average rate of increase of global mean temperature during the next century is estimated to be about 0.3°C per decade (with an uncertainty range of 0.2°C to 0.5°C).”

ix http://www.metoffice.gov.uk/weather/marine/observations/gathering_data/argo.html

x Ocean temperature measurements before Argo are nearly worthless. Before Argo, ocean temperature was measured with buckets or with bathythermographs (XBTs) — which are expendable probes lowered into the water, transmitting temperature and pressure data back along a pair of thin wires. Nearly all measurements were from ships along the main commercial shipping lanes, so geographical coverage of the world’s oceans was poor—for example the huge southern oceans were not monitored. XBTs do not go as deep as Argo floats, and their data is much less precise and much less accurate (for one thing, they move too quickly through the water to come to thermal equilibrium with the water they are trying to measure).

xi The climate models project ocean heat content increasing at about 0.7 × 10^22 Joules per year. See Hansen et al, 2005: Earth’s energy imbalance: Confirmation and implications. Science, 308, 1431-1435, page 1432 (pubs.giss.nasa.gov/cgi-bin/abstract.cgi?id=ha00110y), where the increase in ocean heat content per square meter of surface, in the upper 750m, according to typical models, is 6.0 Watt·year/m2 per year, which converts to 0.7 × 10^22 Joules per year for the entire ocean as explained at bobtisdale.wordpress.com/2011/06/14/giss-ohc-model-trends-one-question-answered-another-uncovered/.

xii The ocean heat content down to 700m as measured by Argo is now available; you can download it from ftp://ftp.nodc.noaa.gov/pub/data.nodc/woa/DATA_ANALYSIS/3M_HEAT_CONTENT/DATA/basin/3month/ohc_levitus_climdash_seasonal.csv. The numbers are the changes in average heat for the three months, in units of 10^22 Joules, seasonally adjusted. The Argo system started in mid-2003, so we started the data at 2003-6.

xiii The weather balloon data showing the atmospheric warming pattern was finally released in 2006, in the US Climate Change Science Program, 2006, part E of Figure 5.7, on page 116 (www.climatescience.gov/Library/sap/sap1-1/finalreport/sap1-1-final-chap5.pdf).

There is no other data for this period, and we cannot collect more data on atmospheric warming during global warming until global warming resumes. This is the only data there is. Btw, isn’t this an obscure place to release such important and pivotal data – you don’t suppose they are trying to hide something, do you?

xiv See previous endnote.

xv Any climate model, for example, IPCC Assessment Report 4, 2007, Chapter 9, page 675, which is also on the web at http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch9s9-2-2.html (Figure 9.1 parts c and f). There was little warming 1959 – 1977, so the commonly available 1959 – 1999 simulations work as well.

xvi So the multiplier in the second box in Figures 1 and 2 is at most 1.0.

xvii Lindzen and Choi 2009, Geophysical Research Letters Vol. 36: http://www.drroyspencer.com/Lindzen-and-Choi-GRL-2009.pdf. The paper was corrected after some criticism, coming to essentially the same result again in 2011: www-eaps.mit.edu/faculty/lindzen/236-Lindzen-Choi-2011.pdf.

xviii In particular, we have not quoted results from land thermometers, or from sparse sampling by buckets and XBT’s at sea. Land thermometers are notoriously susceptible to localized effects – see Is the Western Climate Establishment Corrupt? by the same author: jonova.s3.amazonaws.com/corruption/climate-corruption.pdf.

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onion

Your figure one and figure two are the same

REPLY:
Fixed thanks, a formatting error led to a duplicate. Scourge of document conversion – Anthony

novareason

First photo “What the Government Climate Scientists Say” is the same as the second photo. Think you put the wrong one there, should be x3 in the box.

Kurt in Switzerland

Coherent argument, multiple footnotes.
This should be carried in major media outlets.
Kurt in Switzerland

mark wagner

Figures 1 and 2 are identical. Text indicates that they should show something different.

Kevin

There seems to be a typo in the box summarising the feedback; should it be x3

Tony McGough

The mixup in diagrams is a FATAL FLAW : please fix prontissimo.
REPLY: Using the refresh button helps too – Anthony

novareason

Simple and easy to read, states the case beautifully, and really examines how fraudulent any supposed case for catastrophic warming is.

Peter Miller

Heretic, how dare you quote the facts!
Official Team response.

George

Check Figure 1 – it is missing the X3 amplification box show in the original paper

Ian W

The matching figure 1 and 2 mistake appears to be from the original PDF file.
REPLY: Yes I know, the PDF file has been fixed also…Anthony

Ian _UK

The first and second diagrams seem to me to be identical. Should the first one have a X 3 function, not x 0.5?
REPLY: This was fixed a couple of minutes after publication, try the refresh button on your browser – Anthony

DaveG

Clear and precise with no Ambiguity of information. In Hockey terms this is a SLAP SHOT or a HOLE IN ONE well done Dr David Evans. Lets see what the rent seekers come up with in reply, I already know and can see the cut and paste crowd at work.

Brian H

So, “serious skeptic”, how is Fig. 4 consistent with the “agreed-upon” 1.1K in Figs. 1 & 2??
I assert that the 1.1K is inappropriately extrapolated laboratory data, and should be at most 0.1, negligibly different from 0.0K, and further assert that that is H0.
Fig. 4 indicates that there is no evidence to the contrary.

Now surely, dr Evans, we are not going to let facts stand in our way (tongue in cheek)

Dave_G

Well….. what more can you say?

Brian H

Further to the above: G&T are right. You are wrong.

Ian _UK

And another thing. I read elsewhere that there are hundreds of phenomena or processes that could affect climate (per the study being promoted by WUWT). Doesn’t the essence of this paper, being all about concentration on carbon dioxide/temperature/feedbacks, rather help the warmists’ case?

Dr. Evans
The exposition is marvelous, however I do have a question on the 1.1 degree direct effect of CO2. Can you provide the source for this prediction that after unraveling does not point back to Hansen’s empirical relationship?
In Loudon’s textbook on Quantum mechanics there are two primary means whereby an increase in the partial pressure of an IR absorbing gas such as CO2 increases absorption. The first is a Lorentz pressure broadening and the variable term of pressure is against the entire atmosphere, not the self pressurization of the IR absorbing gas. The second is temperature broadening which is also a Lorentz transformation from the gaussian function for the QM energy absorption/emission of the gas (CO2).
In running the equations in Loudon with the increase in the partial pressure of CO2 from 0.028% of the atmosphere to 0.39% of the atmosphere does not result in a 1.1 degree temperature increase. Obviously there are more calculations involved related to the statistical mean time between absorption and emission against the mechanical transfer of the increased energy in the CO2 molecule to another non CO2 molecule but no fundamental equation that I have seen can, at the partial pressure of CO2 observed, produce the 1.1 degree result.
What is wrong here?

I am a little unsure about what the figures are saying in regards to doubling of CO2. I thought that for each doubling of CO2, you had a logarithmic increase in temperature. The figures make it seem as though the relationship is linear and every doubling of CO2 led to a 1.1 degree increase in temperature.
REPLY: Typo related to format conversion image/cut/paste – now fixed – Anthony

Jeremy

The posts under David’s original blog has some good discourse also. A skeptic brings up some rubbish “slayer” arguments that are sometimes used to attack the CAGW meme but, being titally wrong, only serve to discredit the skeptics. David Evans obviously understands Physics very well and explains why these “slayer” arguments are just plain wrong. Excellent.
I realize Anthony Watts and his crew, not being Physicists, cannot be expected to correct the occasional egregious Physics errors committed from time to time on WUWT. However, WUWT is so well supported, has a large community, is uncensored, and is full of such diverse and interesting content (as well as posts) that I am quite wiling to overlook the odd articles/posts on WUWT that makes us few Physicists cringe.

Jack Langdon

The blue box is wrong in fig 1. Should be 3x
REPLY: Try the refresh button on your browser -A

I think it is the “sceptic’s case” in respect to CO2, and there is a whole lot more going on. But they are sceptics about CO2, so it is quite correct.

Ally E.

Yep, I’m adding my voice to Onion and Novareason. Please fix this first figure before too many copies get sent out.
Aside from that, this is great. Cheers.
REPLY: Apparently nobody knows how to use the refresh button, it has been fixed just a couple minutes after it was published. – Anthony

scottd0317

I’m not a scientist but I am a grammarian. The word “data” is the plural of “datum.” Therefore the proper usage is “the data say” not “the data says.”

We are now 22 years into the global warming story. This is a very good summary of how the crux of the argument has always been just about water feedbacks. In my opinion the evidence clearly rules out the large feedback factors that are still used by climate models – as do arguments from the faint sun paradox. All this should be welcomed as good news, and surely scientists would now want to bring this to the public’s attention – rather than apparently wishing the evidence away! This area of science seems to have got embroiled with politics and various vested interests. This paper is a good start and needs more exposure.
Note: Figure 1 should have feedback x 3.0 (not 0.5!) The PDF file has the same problem.

Skeptic

Please fix the feedback parameter in the first graphic!
REPLY: It has been noted and fixed, please read other comments before piling on – Anthony

What a lot of the skeptic scientist generally have missed is that the 1.1 deg C rise with CO2 doubling comes from a calculation in which the IPCC brains unilaterally and for no good reason (other than their desired agenda) multiplied the thermodynamic factor for CO2 (effectively, the probability factor regarding the chances of a CO2 molecule colliding with another molecule during the instant between IR absorption and IR re-emission, allowing the energy to become heat energy) by a whopping factor of 12, bumping the warming from 0.1 deg C to 1.1–1.2 deg C.
This was patently dishonest, but they NEEDED to make CO2 more effective. All the while, they masked their duplicity by lauding and marveling how constant this (now inflated) factor had been in the literature over time.
It’s too bad that so many skeptics honor this falsehood, just as so many honor the false CO2 graph composed of Arctic ice core and Mauna Loa volcano data and validate it in discussions as if it was true. It’s cherry-picked and manipulated data and has to be labeled so as often as it comes up.
“Wow, it’s such a hot day!” he said, while turning up the heat. “It must be global warming.”
We HAVE to keep checking the thermostat on these guys or we end up arguing nonsense.

nomnom

Figure 3 is wrong. The lines for scenarios A,B and C in Hansen’s 1988 graph did not start at the same place in 1988 as depicted in figure 3.

Useful summary. Well done!
Minor point: the rhs in each of Figs 1 and 2 should be ‘predicted’ or ‘expected’, and not ‘observed’.

Dear Dr, Evans.
Thank you for this. You can’t get any more Lay than I am and I managed to follow your argument well enough. The only area of confusion is at the top, where you describe the basic positions of sceptic and warmist. A second diagram in each case, describing the differences over feedback effects, could make things even more clear.

scepticalwombat

Figures 1 and 2 are misleading in that they look at changes in temperature rather than actual temperatures. No one ever said that temperatures would increase steadily and in fact all the projections and models suggested that after the major El Nino peak in 1998 there should be a return to the trend line which implies that temperatures should fall or at least stop increasing in order to return to the trend line. The fact that they have done that should be no surprise and certainly does not invalidate the models.

David, this is overall an excellent exposition and I know how difficult it is to write a concise debunking of CAGW. There is however one weakness that I’m sure the CAGWers will exploit viz: in Figure 3 you compare Hansen’s 1988 projections with the UAH satellite tropospheric temperature record. My recollection is that Hansen’s projections were surface air temperatures, rather than lower troposphere. I don’t think a spaghetti graph would help here — rather a sentence explaining why you choose UAH.
[Aside] I am recalling the screaming of a CAGW fanatic screaming far too loudly for comfort: “cherry-picker, cherry-picker…” during David Archibald’s presentation when he and Anthony visited Hobart not so very long ago. [/Aside]

HankHenry

I’ve been ill served by popular media. It has taken a lot of reading on my part to become aware of the existence of feedbacks in global warming theory, yet this is what the theory of the crisis hinges on.

William M. Connolley

[snip – reword this and resubmit, without making accusations -Anthony]

[q]I am a little unsure about what the figures are saying in regards to doubling of CO2. I thought that for each doubling of CO2, you had a logarithmic increase in temperature. The figures make it seem as though the relationship is linear and every doubling of CO2 led to a 1.1 degree increase in temperature.
REPLY: Typo related to format conversion image/cut/paste – now fixed – Anthony[/q]
Having read this paper over at Mises.org, oddly enough I figured that you would have fixed the graphic soon after I posted my comment (and you did) so I was commenting on the what would be the fixed graphics (if that makes any sense).
Both figures are saying that every doubling of CO2 leads to a direct 1.1 degree increase in temperature. But the CO2/Temperature relationship is logarithmic: http://wattsupwiththat.com/2010/03/08/the-logarithmic-effect-of-carbon-dioxide/
I don’t know if it is something that Dr. Evan overlooked or if it is just a poor or simplified wording, but the figures are implying the direct relationship between CO2 and temperature are stronger than they are.

RACookPE1978

scepticalwombat says:
February 26, 2012 at 12:09 pm
Figures 1 and 2 are misleading in that they look at changes in temperature rather than actual temperatures. No one ever said that temperatures would increase steadily and in fact all the projections and models suggested that after the major El Nino peak in 1998 there should be a return to the trend line which implies that temperatures should fall or at least stop increasing in order to return to the trend line. The fact that they have done that should be no surprise and certainly does not invalidate the models.

I most firmly disagree: NO published model result of ANY of the 23 known GCM used thus far has predicted a 15 year flat period while CO2 levels increase. NONE.
At best, Steve Mosher has indicated informally on this site that 3% of the total model results show a flat period, but the remaining 97% of the total computer runs continue to “falt line” in s nice neat straight “average” line linearly increasing with CO2 increases. ALL published results use “averages” of dozens to hundreds of model runs as their result.
Further, NO model results have EVER predicted ANY El Nino or La Nina period, much less the 1998 super-El-Nino. This includes back-casting and forecasting: No model results shows a El Nino spike or La Nina dip caused by those oscillations in the mid-Pacific winds and currents.
Now, to be fair, I will leave you to prove your statement by showing either the 3% of the runs that Mosher mentioned, or a published result of any 15 year flat period.

Bill H

Very Nice Anthony..
the data in simple understandable format… but the AGW faithful will cry heretic!
Reality… what a concept…

Alvin

Yes, need to re-publish the PDF as well. The warmist feedback is incorrect as well.

William M. Connolley

> I thought that for each doubling of CO2, you had a logarithmic increase in temperature.
No. Temperature change is roughly linear in log(CO2 change).

REPLY:
Is it really? That is what you and the rest of RealClimate believes, but observations and other calculations suggest that isn’t actually the case. From http://wattsupwiththat.com/2009/10/25/what-does-a-reduction-to-350-ppm-of-co2-get-you/

For a short period of time, such as our history of CO2 measurement, it appears as linear, but on the larger scale, not so much. – Anthony

Bob Meyer

That’s the best summary of the skeptics case that I have seen. Thanks.

higley7 said @ February 26, 2012 at 12:06 pm

What a lot of the skeptic scientist generally have missed is that the 1.1 deg C rise with CO2 doubling comes from a calculation in which the IPCC brains unilaterally and for no good reason…

Wrong! It comes from MODTRAN a computer program designed to model atmospheric propagation of electromagnetic radiation for the 100-50,000 cm-1 (0.2 to 100 um) spectral range by Spectral Sciences Inc. and the US Air Force. You do understand that there is a difference between these organisations and the IPCC?

Anonymous

Figure 7 could be more clear. It would be helpful to separate the actual ERBE data from all others by using a different color or setting it apart somehow. At first and second looks, it appears that ERBE is simply an outlier amongst many data sets, rather than being the only data amongst many models.

nomnom

David Evans can you explain how and why you altered Hansen’s scenario A, B and C lines in figures 3 and 4? I presume there was a good reason to do so, but wouldn’t it have been clearer to just leave them unmodified? I don’t see how it helps to modify the prediction if you want to test the prediction.
I notice for example that in figure 3 and 4 you show Hansen’s 3 scenarios meeting in the year 2008. That doesn’t occur in Hansen’s original, in fact scenarios A and C are far apart in 2008:
http://www.zeeburgnieuws.nl/nieuws/images/hansen_1988_temp_prediction.jpg
Obviously something has been shifted up or down. What though? and why?

jaypan

Excellent work. Thank you.

Policy Guy

Well done. Very clear and understandable.
How can a piece like this be submitted for formal publication and peer review? Might that be in the works? I wonder what Revkin would say about this presentation?

pkirk21 said @ February 26, 2012 at 12:17 pm

[q]I am a little unsure about what the figures are saying in regards to doubling of CO2. I thought that for each doubling of CO2, you had a logarithmic increase in temperature.

No, the temperature increase falls off rapidly as more CO2 is added. Almost everyone uses MODTRAN to do the sums.

haha, nevermind :). The pdf still shows the incorrect image though. Just a head’s up.
REPLY: No, it doesn’t: http://wattsupwiththat.files.wordpress.com/2012/02/theskepticscase.pdf
-Anthony

scepticalwombat

Sorry – that should be figures 4 and 5.

DirkH

nomnom says:
February 26, 2012 at 12:25 pm
“Obviously something has been shifted up or down. What though? and why?”
Consult the footnotes.
“vi Hansen’s predictions were made in Hansen et al, Journal of Geophysical Research, Vol 93 No D8 (20 Aug 1988) Fig 3a Page 9347: pubs.giss.nasa.gov/docs/1988/1988_Hansen_etal.pdf. In the graph here, Hansen’s three scenarios are graphed to start from the same point in mid-1987 – we are only interested in changes (anomalies).”

Martin Lewitt

I don’t think this should be presented as “the” skeptical case. While there isn’t model independent evidence to support large climate sensitivities to CO2 forcing in the current climate regime, there also is not conclusive evidence that the net feedbacks are actually negative, although Lindzen, Spencer and others have work arguing that, and the long term stability of the climate is suggestive of that. A positive assertion of a climate sensitivity of 0.6 degrees C, leaves about 80% of the recent warming unexplained rather than the two-thirds to be explained with the direct effects of CO2 forcing. There are plenty of good candidates, anthropogenic black carbon, anthropogenic aerosols (reduction), natural variation (e.g., PDO and other multi-decade climate modes) and solar activity. The IPCC conclusions and confidence are not warranted by the evidence. One can be skeptical based just upon the model diagnostic issues and the lack of model independent evidence for high sensitivities relevant on the time scales of interest, and being unable to reject mostly natural variation, or a sensitivity of 1.1C or even 0.6C as null hypotheses.