NOTE: This post is the second in the series from Dr. Roy Spencer of the National Space Science and Technology Center at University of Alabama, Huntsville. The first, made last Friday, was called Atmospheric CO2 Increases: Could the Ocean, Rather Than Mankind, Be the Reason?
Due to the high interest and debate his first post has generated, Dr. Spencer asked me to make this second one, and I’m happy to oblige.
Here is part2 of Dr. Spencer’s essay on CO2 without any editing or commentary on my part.
(Side note: Previously, I erroneously reported that Dr. Spencer was out of the country. Not so. That was my mistake and a confusion with an email autoresponse from another person named “Roy”. Hence this new update.)
More CO2 Peculiarities: The C13/C12 Isotope Ratio
Roy W. Spencer
January 28, 2008
In my previous post, I showed evidence for the possibility that there is a natural component to the rise in concentration of CO2 in the atmosphere. Briefly, the inter-annual co-variability in Southern Hemisphere SST and Mauna Loa CO2 was more than large enough to explain the long-term trend in CO2. Of course, some portion of the Mauna Loa increase must be anthropogenic, but it is not clear that it is entirely so.
Well, now I’m going to provide what appears to be further evidence that there could be a substantial natural source of the long-term increase in CO2.
One of the purported signatures of anthropogenic CO2 is the carbon isotope ratio, C13/C12. The “natural” C13 content of CO2 is just over 1.1%. In contrast, the C13 content of the CO2 produced by burning of fossil fuels is claimed to be slightly smaller – just under 1.1%.
The concentration of C13 isn’t reported directly, it is given as “dC13”, which is computed as:
“dC13 = 1000* {([C13/C12]sample / [C13/C12]std ) – 1
The plot of the monthly averages of this index from Mauna Loa is shown in Fig. 1.
Now, as we burn fossil fuels, the ratio of C13 to C12 is going down. From what I can find digging around on the Internet, some people think this is the signature of anthropogenic emissions. But if you examine the above equation, you will see that the C13 index that is reported can go down not only from decreasing C13 content, but also from an increasing C12 content (the other 98.9% of the CO2).
If we convert the data in Fig. 1 into C13 content, we find that the C13 content of the atmosphere is increasing (Fig. 2).
So, as the CO2 content of the atmosphere has increased, so has the C13 content…which, of course, makes sense when one realizes that fossil-fuel CO2 has only very slightly less C13 than “natural” CO2 (about 2.6% less in relative terms). If you add more CO2, whether from a natural or anthropogenic source, you are going to add more C13.
The question is: how does the rate of increase in C13 compare to the CO2 increase from natural versus anthropogenic sources?
First, lets look at the C13 versus C12 for the linear trend portion of these data (Fig. 3).
The slope of this line (1.0952%) represents the ratio of C13 variability to C12 variability associated with the trend signals. When we compare this to what is to be expected from pure fossil CO2 (1.0945%), it is very close indeed: 97.5% of the way from “natural” C13 content (1.12372%) to the fossil content.
At this point, one might say, “There it is! The anthropogenic signal!”. But, alas, the story doesn’t end there.
If we remove the trend from the data to look at the inter-annual signals in CO2 and C13, we get the curves shown in Figures 4 and 5.
Note the strong similarity – the C13 variations very closely follow the C12 variations, which again (as in my previous post) are related to SST variations (e.g. the strong signal during the 1997-98 El Nino event).
Now, when we look at the ratio of these inter-annual signals like we did from the trends in Fig. 3, we get the relationship seen in Fig. 6.
Significantly, note that the ratio of C13 variability to CO2 variability is EXACTLY THE SAME as that seen in the trends!
BOTTOM LINE: If the C13/C12 relationship during NATURAL inter-annual variability is the same as that found for the trends, how can people claim that the trend signal is MANMADE??
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Perhaps, but also no reason for knee-jerking doom and gloom. We KNOW plant life thrived in higher CO2 concentrations in the past. Whether all will now or in the future is irrelevant, they’ll adapt or die, it’s always the way, whether we’re here or not.
Ferdinand,
Thanks for your reasoned and thoughtful response. One of the main reasons I come here is to learn, and I learned something new today.
Just to further clarify; are you saying that the CO2 in the air we breathe in is a negligible part of the CO2 we exhale, and that, in fact, most of the CO2 we exhale is a waste product of the respiration process itself?
Sorry, Loquor, I did not intend to say that you were espousing the doom and gloom scenarios. But there are many who do.
I do not think it is a stretch at all to say that effectively all plants will benefit from more CO2. That doesn’t mean we should just dump more CO2 for the purpose of helping plants. As for Maize, generall planted corn DOES receive enhanced ground nutrients through human fertilization, so I don’t understand why it wouldn’t benefit from more CO2 as well. It’s also a highly hybridized plant at this point, so there’s no reason to believe we couldn’t hybridize a more “CO2 tolerant” 😉 version.
That’s just the point, though. Any point in time is a loosely picked condition X. Wait a few thousand years and the conditions could be wholly different.
My opinion of the ENTIRE AGW situation is that we’ve only gotten better at scrutinizing things (and there are a lot more people around to scrutinize the planet) and that any perceived change from some arbitrary “normal” is seen as dangerous. I just don’t see any merit to that position. Disastrous is a relative term. We see hurricanes and forest fires as disastrous, but they’re a critical part of nature, they HAVE to occur.
loquor,
I am following your reasoning to a certain extent.
Where we differ is the extent of the consequences of the extra CO2 we add to the atmosphere, which are twofold.
1) the effect of CO2 on temperature. From the past (the end of the Eemian), we know that a 40 ppmv drop in CO2 has no measurable effect on temperature.
Current “projections” of GCM’s are heavily based on the (overestimated) effect of aerosols, to explain the 1945-1975 temperature drop with increasing CO2 levels. That is the main reason that they overestimate future temperatures. And recent (7 years) temperatures are quite steady, while CO2 increased steadily…
2) If the doubling of CO2 around the end of this century will have much effect on food crops yield or on the quality of the food remains to be seen. The protein/carbohydrate ratio of leaves seems somewhat reduced in field tests, but seeds show little difference in nutritients.
Thus we still have some time to see if all these scaring stories come into effect, but anyway we need to do a lot more research for alternatives and especially the possibility to store a lot of power, if it is only to be less dependable from not so stable oil-rich countries…
But I agree with you that Dr. Spencer should drop this topic, it is undefendable and does harm to the sceptics in general. There are more than enough genuine problems with AGW which need to be questioned on real scientific grounds…
I have read the claims about CO2 being bad for C4 plants, however, I find these claims extremely simplistic. I have been periodically reading more detailed information on this site:
http://www.co2science.org/scripts/CO2ScienceB2C/articles/V7/N30/B1.jsp
“Contrary to what many people had long assumed would be the case for a C4 crop such as corn growing under the best of natural conditions, Leakey et al. found that “growth at elevated CO2 significantly increased leaf photosynthetic CO2 uptake rate by up to 41%.” The highest whole-day increase was 21% (11 July) followed by 11% (22 July), during a period of low rainfall.”
In the worst case scenario more CO2 had no effect on plant growth.
However, this data does not take into account that higher CO2 means plants need less water which would reduce the need for irrigation and led to higher yields even if CO2 reduced productivity (which it does not appear to do).
Bottom line is I don’t put much weight on claims by alarmists that higher CO2 puts our food supply at risk.
Ferdinand,
I think you are right that we disagree about AGW, Ibut I respect your point of view – clearly there are legitimate reasons for SOME skepticism…
I have read numerous papers about positive and negative forcings, sensitivity and the like, but as a biologist, I am not really qualified to speak out about this in other than broad terms, so maybe we should not discuss this at lengths here.
I will, however, say that I think it is very unwise of skeptics to emphasise the apparently steady temperatures since the great El Nino in 1998. While I understand that this is not exactly what you are saying, it appears as if your argument is going in that direction. We all know that this year was well above expectations and quite unusual (believe me, I personally spent this year in Central America ;). In fact, many skeptics – among those Robert Carter and Spencer himself – then said that one should not jump to conclusions about disastrous warming based on “one exceptionally warm El Nino year”. And while I agree completely to that (I do not deny that some “alarmists” do make silly claims based on such events), I am disappointed (but not surprised) to see Carter, Spencer and all the same people now claiming flat out that “Global warming has stopped” based on a trend starting from exactly this very same year. So apparently 1998 is a too unusual year to be used as an endpoint to calculate a trend over 50 years, but somehow it is just magnificent as a starting point to make a seven-eight year trend and accompagnying putative projections about future warming You do not have to be the slightest “alarmist” to spot this blatant inconsistency.
By the same standards, global warming also stopped in 1945, in 1983 and 1990 judged by the CRU record. And actually, temperatures have been steadily rising since 2000:
http://www.cru.uea.ac.uk/cru/info/warming/
I am not sure I understand what you are referring to by “models overpredicting future warming”? As for the future temperatures, to my knowledge nobody claims that temperature and co2 follow each other linearly, and neither do any modeller have this as a prerequisite for their modelling. As far as I know, nobody disputes that co2 alone will lead to a warming for about 1C at doubling, and almost everything I have read of empirical work points to significant positive feedback from water vapour. We do not know yet if the models will show skill in the future, but clearly there is nothing really suggesting that the sensitivity estimates are far off, which means that we are heading for warming at least in the lower levels of the IPCC projections even if we are quite optimistic.
You may disagree, and you may know something I do not. Anyway, I am happy to see a “skeptic”, if I can call you this, have integrity to set obvious nonsense from his own side straight when he sees it. But I really cannot emphasise enough that even if there is unnecessary scaremongering and occasional wild claims from the alarmist camp, you do not hear any distortions or willful misleadings remotely like Spencers writings here from the pro-AGW scientists. Why does Michaels erase Hansens two lower scenarios in his resume of his testimony? Why does Lindzen quote Khilyuk and Chilingar as a credible source, when he knows that their claim “humans may be responsible for less than 0,01C of the warming” are based on the same fallacious reasoning as Spencer´s here? How on earth can Tim Ball claim that it has been cooling down since 1930 (i.e, how on this earth)? And how can Spencer, who has a PhD in physics/atmospheric sciences possibly be unaware about very simple co2-isotope measurements and ocean/atmosphere interactions that we biologists learned on the second year?
I find it awfully hard to believe that Spencer could have written this rubbish in good faith, and with his double standards with respect to El Nino/1998 mentioned above in mind, he only reinforces the impression of dishonesty.
I can forgive him for speaking nonsense about creationism, since he obviously has no clue about evolutionary biology (and you should respect people´s faith), but when he makes statements about his own subject which even I can easily spot are outright lies, then I simply think that Spencer is a disgrace to his profession.
By any objective standards, there is simply a level of dishonesty in the skeptics camp that really makes it difficult to believe any claims from these people.
Sorry for the rant, it is not directed towards you personally. However, when you started to speak about the “genuine problems” of AGW, then I felt it necessary to point out that there is by far more problems with standard skeptic arguments that are not at all genuine.
And Raven, while I do not trust the Idsos much either (they are, among other dubious things, also making the same hopeless claims about a possible large natural sources of the co2 rise), I do agree that the science on the response of C4 plants on enhaced co2 is by no means settled. I make no claim that out food supply will come at risk. I only brought this up because Jeff made the widely repeated claim about how plants will thrive on enhanced co2 – and this definitely is not supported by the evidence, either, and I just think it is important to point that out.
“Sorry, Loquor, I did not intend to say that you were espousing the doom and gloom scenarios. But there are many who do”.
No problem! 🙂
“I do not think it is a stretch at all to say that effectively all plants will benefit from more CO2. That doesn’t mean we should just dump more CO2 for the purpose of helping plants. As for Maize, generall planted corn DOES receive enhanced ground nutrients through human fertilization, so I don’t understand why it wouldn’t benefit from more CO2 as well. It’s also a highly hybridized plant at this point, so there’s no reason to believe we couldn’t hybridize a more “CO2 tolerant” version”.
Well, as said I do not think that the science is settled about co2 and plants under natural (i.e. outside greenhouses) conditions at all. What I can see is that the science that has been done clearly does not support any wild optimism about how plants will prosper.
As for the theoretical reasons why maize might not benefit and even be harmed from enhanced co2, I suggest you read the wikipedia links I provided about C3 and C4 metabolism (I take it that you are not a biologist). Shortly speaking, C3 plants are not as efficient in their co2 uptake as are C4 plants due to their different mechanisms of controlling the uptake through the closing and opening of their stomata – C4 lowers the so-called photorespiration level. Therefore, under co2 depletion C4 plants have an evolutionary advantage. However, this diminishes when co2 rises. Actually one hypothesis about the origin of C3 metabolism is that it is a relic of times when co2 levels were higher and oxygen levels lower. What this will mean in practice and with GMOs is unclear, and again I definitely do not want to make and firm statements about these problems. But there are just as good theoretical and practical arguments to expect the opposite of what you are claiming.
“That’s just the point, though. Any point in time is a loosely picked condition X. Wait a few thousand years and the conditions could be wholly different”.
Well, no. When you want to make reasonable inferences about Holocene climate, then the last Interglacial is clearly a better starting point than under Snowball Earth, the carboniferous or early Precambrium. When you want to make inferences about present-day like plants prospering under enhanced future co2 levels, then singling out the Carboniferous – where no flowering plants and hardly any seed plants existed at all – is a particularly poor choice for a meaningful comparison. Some points are indeed not loosely picked condition X – it is the base of the standard climatological reasoning that you can make meaningful inferences about co2 effects in Holocene by comparisons with last interglacial, but not so in the case of the Andean ice age 450 mio. years ago.
“My opinion of the ENTIRE AGW situation is that we’ve only gotten better at scrutinizing things (and there are a lot more people around to scrutinize the planet) and that any perceived change from some arbitrary “normal” is seen as dangerous. I just don’t see any merit to that position. Disastrous is a relative term. We see hurricanes and forest fires as disastrous, but they’re a critical part of nature, they HAVE to occur”.
OK, that is true. We have to accept that there are things that we cannot change, and maybe some AGW proponents have a problem with that. I can only speak for myself when saying that this is not my point of view. I just still think that even if things “have to occur naturally”, then this is no argument that we should not worry about what we can only perceive as disasters as human beings – especially not if we are indeed pushing for enhancing such disasters in the future.
We all have to die quite naturally, too, but this does not mean that spontaneous murder is a thing that we would not want to do something about, even if it is “completely natural”…….;)
Loquor, I’m not sure what “spontaneous murder” is meant to convey.
But all I can say is, if we want to cause NO harm to the planet, then we have to forgo all industrial activity and revert t hunter-gatherers. A great many of us will die, but it’s the only way humans can subsist with nature in a way that doesn’t de-forest, change the CO2 balance, etc. You might disagree and say there is a technological solution. But that won’t prevent humans from populating themselves out of existence (not saying this will happen in any foreseeable generation, but we’ve been hearing it for many years), and clearing hectare after hectare for housing, business, farms, etc. CO2 will be the least of any conceivable problem one might have.
Besides, the one thing we can all be sure of is that there will be another ice age and atmospheric CO2 will be dust in the wind, literally.
Re loquor (15:11:14) :
quote I do agree that the science on the response of C4 plants on enhanced co2 is by no means settled. I make no claim that out food supply will come at risk. unquote
The great advantage of the C4 mechanism (and CAM) is, I was taught, not its frugality in carbon dioxide use but it’s water-saving advantages. Do the deserts green as CO2 levels rise?
On a lighter level, I give a recipe tip: pick your vine leaves for dolmades just as the sun comes up — the malic acid stored over night lends an unmatched piquancy. Vines are CAM plants.
JF
JF
loquor,
Indeed I am a luke-warm skeptic (to both sides of the fence), I am pretty sure that we are responsible for the CO2 rise, but I am also pretty sure of the overestimates of current GCM’s.
About current temperatures: since 2000 (excluding the 1998 El Niño and the 1999 La Niña) global temperatures are completely flat. That is visible in the CRU link you provided, as even the 5-years average halted.
This is not (yet) proof of the disconnection between GHGs and temperature, as one need a longer time frame and we are at a solar minimum (which gives a +/- 0.1°C variation over a complete cycle).
As far as I know, there are no direct changes in e.g. aerosol emissions (there is a huge shift between the Western world and the Far East, but not in total), which should cause the flat temperature with rising CO2 levels, neither volcanic eruptions. And the oceans are not rising in temperature too (there even were some rumours about cooling, but these were based on problems with the sea temperature measurements).
Thus the next five years will be very interesting…
There are a few basic problems with current models. The most important are:
1) Models assume that the same forcing (in W/m2) has near the same effect on climate, no matter the origin of the forcing.
2) There is a huge offset between GHG effect and aerosol effect.
3) All models see cloud changes as a positive feedback of GHG warming.
About 1)
The main effect of e.g. solar variations (and volcanic eruptions) is in the stratosphere. This changes ozone layer thickness, stratospheric temperatures and jet stream position. The effect on climate is visible in cloud/rain/wind patterns, river discharges, (low) cloud amount and temperature over the solar cycle(s).
There main effect of GHG increase and aerosols is in the lower troposphere. There is no clear pattern of CO2 increase on the above variables, except for an increase of total precipitation (about 6% over 60 years in the Arctic), but even that may be solar driven.
Thus that all GCM’s use the same “efficacy” for the same change in forcing doesn’t take into account the difference in effect of stratospheric vs. lower troposphere changes and especially the effect on cloud formation.
That GCM’s underestimate solar influences (about a factor 2) can be seen in an attribution study of the HadCM3 model by Stott ea.:
http://climate.envsci.rutgers.edu/pdf/StottEtAl.pdf
Even that is probably an underestimate, as they worked with a fixed influence of aerosols (-1.5 W/m2).
About 2)
Models need to follow the 1900-2000 temperature trend, that is a necessary, but insufficient condition. As we have 4 independent variables (GHGs, aerosols, solar and volcanoes), we can match any previous trend by abandoning the fixed forcing/effect ratio for the different variables. Especially the GHG/aerosol tandem is of interest. You can halve the influence of CO2 if you reduce the influence of aerosols to one quarter, see:
http://www.ferdinand-engelbeen.be/klimaat/oxford.html
That means that if the sensitivity of climate to CO2 increases is 1.5°C instead of 3°C for 2xCO2 in average current models, there is hardly any reason for panic. This is physically possible, if we take into account that clouds are badly defined in current models and may give a negative feedback, not a positive one. The temperature increase of 2xCO2 is about 0.68°C (based on absorbance), with water vapour feedback: 0.89°C, the rest of the 3°C in current models is from very unsure positive/negative feedbacks like clouds…
See: http://home.casema.nl/errenwijlens/co2/howmuch.htm
About 3)
Current models completely fail reality of cloud cover in the tropics and the Arctic…
See: http://www.nerc-essc.ac.uk/~rpa/PAPERS/olr_grl.pdf
and http://www.cicero.uio.no/fulltext/index_e.aspx?id=3277
From the latter:
“the models overestimate the cloud cover in the winter and underestimate it in the summer.”
That has a tremendous influence on temperature predictions in the Arctic…
Jeff, I am just trying to say that to argue that something is “natural” is a poor guide for what decisions we should take on society levels. Extinction, deforestation, erosion, infanticide, diseases and hurricanes are all entirely natural phenomena, but they are also things that most people would agree are undesirable and should be avoided, minimised or at least taken seriously.
I do not pretend to speak for all enviros, but when I argue for taking climate change serious, it has absolutely nothing to do with “divine nature” or such nonexisting things. It is simply a matter of keeping the planet as hospitable a place for humans for as long time as possible.What I am arguing is really the opposite of what is “natural”. In the long run we will all be dead, but to take this perspective to basically every future question as you seem to do is a little sad, do not you think? 😉
(And as an aside, if you drill a bit in the arguments of most GAIA fanatics, you will soon discover that all their arguments boil down to human self-interest behind all the rhetoric, but that is another discussion).
I am not saying that I believe James Hansens´ 6K sensitivity warnings, but in case of temperature increases just half this size (which is a very real possibility), co2 would certainly not be the least of any conceivable problems we might have.
And Julian, the water saving ability is exactly the feature of c4 plants that has to do with the co2 effectivity. Simply put, c3 plants have to leave their stomata open for a much longer time to absorb the same amount of co2 that a c4/CAM plants can absorb in a short time/at night. This causes greater respiration in c3 plants. Higher co2 levels will – in theory and ceteros paribus – give the c3 plants a competitive advantage and c4 plants a disadvantage. I will not try to make any guesses to what this will mean put together with water, sunlight nutrients etc (with respect to Liebigs law of minimum) under real-life conditions in a future world. I am just stating that there is as little empirical and theoretical foundation for predicting greening deserts and thriving plants as for predicting doom and gloom.
I agree completely. Unfortunately when it comes to un-biased reporting on such things, we tend to be out of luck. We seem to only get the Greenpeace view, and if you don’t agree then you’re a planet-hater or something.
I agree, and I think the way to keep the planet as hospitable as possible for humans is through economic growth and technological progress, not needless limitations on a politically-selected atmospheric trace gas.
Which is why we need to be able to adapt, and not attempt to control the global climate. The odds are that the temperature will eventually drop catastrophically, and that’s what we should prepare for.
Ferdinand,
thank you for the comment. Basically, I will make no claims to the GCM model skills, and I am sure that they do have a problem with clouds – I think that even realclimate would grant this freely.
I am not sure if I understand some of your points:
“1) Models assume that the same forcing (in W/m2) has near the same effect on climate, no matter the origin of the forcing”.
Is that exactly true? I mean, do not all models assume that the stratosphere should cool by a 4W/m2 forcing from GHGs, but warm uniformly with the troposphere, came the same 4W/m2 from the sun? And as far as I know, nobody seriously disputes that the stratosphere is indeed cooling, with warming increasing downwards and the mid-troposphere being a little cooler than the surface.
And while they may underestimate solar forcing by a factor of two (or three), a tripling of solar forcing to something like 1 W/m2 would still be nowhere near the level needed to explain a substantial part the present warming, would it? At least not without huge positive feedbacks, which most of the same sceptics want us to believe are SMALLER than expected by IPCC, as you are also suggesting……….
“2) There is a huge offset between GHG effect and aerosol effect”.
In a narrow sense, you are right, and it is clear that this would be a big problem – if we only tried to estimate the sensitivity from the 20th century. It sounds, however, a bit to me like you are repeating Schwartz´points from his “too rosy a picture” paper in which he claimed that the assessments of sensitivity and model skill are based only on the 20th century (where aerosol forcing has been large).
As you probably know, this is not correct. Models are validated against a multitude of pre-20th century events exactly because it has been demonstrated countless times that the 20th century is so unusual with respect to so many forcings and temperature shifts that it is not a good constraint on anything. I could be wrong, but as far as I know, this uncertainty (even at low values of aerosol impacts) would not shift sensitivity estimates for 2xco2 much below about 2C when all lines of evidence in taken into consideration.
“The temperature increase of 2xCO2 is about 0.68°C (based on absorbance), with water vapour feedback: 0.89°C, the rest of the 3°C in current models is from very unsure positive/negative feedbacks like clouds”.
I do not follow your calculations. Based on absorbance (Arrhenius´model) used by IPCC, from here: http://www.esrl.noaa.gov/gmd/aggi/ ), I get
5,35 * log (560/280)=3,7 W/m2. Even excluding all feedbacks and just assuming blackbody conditions (0,25-0,3C/W/m2), this should amount to about 1-1,2C rise due to co2 only.
As Soden and others have demonstrated, there is very good evidence at least for the positive sign of the net feedback from water vapour. This put together surely alone raises the expectations to the sensitivity up somewhere in the lower IPCC range – and this is before we start dealing with aerosols at all (or cloud feedback, albedo and land use).
Is Hans Erren your only source to this? I would be wary of relying too much upon him.
3) “All models see cloud changes as a positive feedback of GHG”.
Again: Is this exactly true? I know that they see water vapour overall as a net positive feedback (which is well documented), but do not some models get a small negative feedback, while others a slightly positive one? As far as I know, what all models have in common is that whatever the sign of the cloud feedback this effect is small compared to the large feedbacks like free water vapour, ice albedo and land use changes.
I am open to the possibility that they could all be wrong in this, but I do not see much in the scientific literature indicating that there are good reasons to believe that they are far off in this.
And finally, even if IPCC and the “alarmists” are wrong in all these aspects, I have not seen them making wild and completely unsubstantiated claims to a degree remotely comparable to what we see from the sceptics. And I do not recall a single documented evidence of an “alarmist” obviously moving the goalposts or lying.
The fact that Spencer, Carter and Lindzen are often spreading information which they know is not true is the one most important reason for my general disrespect towards the sceptic side.
Again, this is not aimed at you (or generally, the commenters here – I really appreciate the sober tone and the reasonable level of discussion in this foum – highly unusual for a climate discussion, my sincere compliments), but I would like to hear your opinion on this.
Regards, L
Loquor wrote: “I really appreciate the sober tone and the reasonable level of discussion in this forum – highly unusual for a climate discussion, my sincere compliments)”
Thank you for noticing, there’s two reasons for it.
1) This site has many participants, heavier on the skeptic side. Skeptics generally don’t resort to the name calling, the labeling, the insults, and the boorish behaviour that we’ve seen on other climate discussion forums.
2) I routinely admonish those who do exhibit such behaviour, because I want everyone to feel like they can comment without being insulted or attacked.
The strategy appears to be working, and the visits and comments to the site have doubled in the last month as a result of this, and the content itself.
Well, your admonitions may have worked for the audience here, and if this is the case, then I congratulate you with your authority. But when you state:
“Skeptics generally don’t resort to the name calling, the labeling, the insults, and the boorish behaviour that we’ve seen on other climate discussion forums”.
then forgive me, but this is patently false. Either you are out in an attempt to put a positive spin on the discussion or you have not visited any other fora with a contribution leaning towards people on the sceptic side.
Lubos Motl´s blog is perhaps the most striking example of a sceptic blog full of concordantly sceptics commentators whose argumentation style pretty much appear to be confined to name calling, labelling, insults and blatant misrepresentations/misunderstandings of the science and nothing else, really. One might think they are just following the style of the administrator there, but this is pretty much the same thrash talk on e.g. climateaudit – an endless parade of people who never check any sources and seem to accept basically everything that goes in the direction that fits the need of their disire to yell, rant and rave about how scientist are only in it for the money and how this is all a big UN/socialist plot and such.
Of course, there is much of the same stuff on “alarmist” blogs. You will probably disagree to this, but I think that the basic things that really tires “alarmists” and mainstream scientists into this counterproductive behaviour is the level of dishonesty that is displayed constantly from “sceptical” scientists. In this regard, there is simply no alarmist counterparts, at least not scientific ones.
If you are an honest scientist thinking that you have a new and groundbreaking hypothesis that pretty much removes the entire foundation for a whole discipline, then every first year student know that rule number one is to make damn sure that you have checked all the important previous research on the subject and that you can adress the load of questions you will inevitably be overloaded with.
It is quite obvious to everyone here that Dr. Spencer has no answer to even basic questions from textbooks and that he appears completely unaware that his “intriguing hypothesis” about a large ocean source for atmospheric co2 rise has been disproven decades ago and that every single one of his claims have been adressed and done to death about a zillion times in the past 30 years. As I said, it is very hard to believe that Dr. Spencer could possibly have spent 30 years as an atmospheric scientist and yet remain unaware of such basic textbook facts.
Then why on earth does he go and produce several thousand words and calculations and write all this up without mentioning any of this? Surely not simply to blow smoke, or…….?
But returning to the positive side, Mr. Watts, then one things that truly does set your blog and your audience apart, though, is the fact that everybody here seem to be open to real scientific evidence and arguments. This is perhaps an even greater source for admiration…………? 😉
Loquor (09:33:46) says:
“And while they may underestimate solar forcing by a factor of two (or three), a tripling of solar forcing to something like 1 W/m2 would still be nowhere near the level needed to explain a substantial part the present warming, would it?”
You are assuming that TSI is the appropriate way to measure solar forcings. It has long been assumed that TSI variations were the reason for solar induced climate changes like the LIA and even the warming in the early 20th. However, recent work with proxies has some solar scientists claiming that the solar proxy data was misinterpreted and that the TSI output from the sun has been not varied at all over the last millennia. This has two implications:
1) Models that ‘predict’ the past by assuming a TSI related forcing are wrong.
2) That we don’t understand the effect of the sun on climate well enough to exclude it as a factor during the most recent warming.
Loquor (09:33:46) says:
“Models are validated against a multitude of pre-20th century events exactly because it has been demonstrated countless times that the 20th century is so unusual with respect to so many forcings and temperature shifts that it is not a good constraint on anything.”
I would say this is an assumption and not an established fact. There is good evidence that the temperature varied just as quickly and deviated by just as much in the recent past.
Loquor (09:33:46) says:
“As Soden and others have demonstrated, there is very good evidence at least for the positive sign of the net feedback from water vapour.”
Even if one accepts that more water vapour does not lead to more precipitation then one must deal with attribution when multiple forcings are present. For example, the ice core data suggests that orbital forcings initiated the warming/cooling and CO2 was added in later. Given this sequence of events it would be most reasonable to attribute any (if not all) water vapour forcings to the orbital forcing because it was the primary driver. This would result in a much lower estimate of CO2 sensitivity than one would get by assuming that all feedbacks (albedo, water vapour, etc) can be attributed to the rising GHGs.
Loquor (09:33:46) says:
“And I do not recall a single documented evidence of an “alarmist” obviously moving the goalposts or lying.”
This happens all of the time.
Example of moving goal posts: real climate never acknowledged the uncertainty in GCMs before Christy et. al. produce dan analysis showing the troposphere temperatures were not keeping up with model predictions. In order to defend the models RC added error bars and cherry picked a dataset happened to fall within those error bars. In other words, RC now insists that the GCMs must be treated as accurate unless all datasets fall outside the 95% confidence interval which happens to include everything from a slight cooling to catastrophic warming. I do not feel this is a reasonable position.
An example of lying: Mann made numerous statements that were later shown to be false (look up the issue regarding the CENSORED data on the CA site).
Loquor (09:33:46) says:
“The fact that Spencer, Carter and Lindzen are often spreading information which they know is not true is the one most important reason for my general disrespect towards the skeptic side.”
I accept that you claim could be true, however, I am skeptical because I have seen many examples where alarmists express a scientific opinion and then claim it to be a fact. They then label any with a different scientific opinion as dishonest because they ignore their “facts”.
Can you give me any example where Spencer, Carter or Lindzen have spread facts (as opposed to opinions) that are not true?
Ferdinand,
I apologise for not posting any references earlier regarding carbon dioxide-bicarbonate fractionations etc. The standard references I point my students to is:
Emrich, K., Ehalt, D.H. and Vogel J.C., 1970, Carbon isotope fractionation during the precipitation of calcium carbonate. Earth and Planetary Science Letters, vol 8, 363-371
Deuser, W.G. and Degens, E.T., 1967, Carbon isotope fractionation in the system CO2 (gas)-CO2(aq)-HCO3-(aq), Nature, v215, 1033
Wendt, I., 1968, Fractionation of carbon isotopes and its temperature dependence in the system CO2 (gas)-CO2 in solution and HCO3- – CO2 in solution. Earth and Planetary Science Letters, v 4, 64-68
Vogel, J.C., Grootes, P.M. and Mook, W.G., 1970, Isotopic fractionation between gaseous and dissolved carbon dioxide. Zeitschrift fur Physik., v230, 225-238
I hope these help.
Basically I agree with your synopsis Ferdinand. The rise in atmospheric CO2 can be attributed largely to burning of fossil fuels. The oxygen-nitrogen ratio measurements, carbon isotopes etc. all point to such a source.
Loquor Thanks again. I haven’t visited Motl’s blog but once, and it crashed my browser so I wouldn’t know. Spencer’s ideas will go the way of “self correcting science” if there is no merit to them. But he deserves the opportunity to find out.
Like with me, I’m regularly criticized for my http://www.surfacestations.org project, and in some cases even heckled. But nonetheless I’m doing the work and we’ll find out the magnitude (if any) of the microsite biases associated with the USHCN weather station network.
Science is as much about learning from failure as it is from triumph. Either way, proven or falsified, I will have accomplished something nobody else has attempted to do.
Raven:
with respect to solar forcings: Are you referring to Solanki and others? Because as far as I remember, they did find problems, but none suggesting that solar forcing could in any way contibute with more than a minor fraction of the total forcing nonetheless.
Model validations /20th century: My wording was unfortunate and I am no expert, but I think that the arguments of Forster, Hegerl, Stott and others like Annan and Hargreaves are not that temperatures have not varied much in the past, but that the unusually rapid co2 rise and the high aerosol forcing of the 20th century put together with the associated climate impacts do not set a sensible constraint on the predictions of long-terms changes. (Annan and Hargreaves used last interglacial to set a tighter constraint on the upper bond of the sensitivity in their article exactly for this reason). Therefore, I think that Ferdinands aerosol criticism is somewhat misplaced.
As with Mann and the hockey stick, I must ask you for more precise sources. While I do not want to defend everything the hockey team have done, it does seem to me that thei results are robust with respect to almost every criticism form McIntyre – they have tried normalisation with other time seriesand used another multivariate method than the criticised PCA, and that did not yiel different results.
And finally with respect to dishonesty: Ask yourself if you truly believe that Spencer was ignorant of the basic co2 isotope facts? And if Patrick Michaels, Robert Carter or Richard Lindzen are? If not, why would all these people quote
Khilyuk and Chilingar who are making the same erroneous and long debunked claims that Spencer advanced here
Here´s Lindzen and Carter:
http://www.staff.livjm.ac.uk/spsbpeis/WE-STERN.pdf
…and Michaels:
http://www.worldclimatereport.com/index.php/2006/12/01/are-humans-involved-in-global-warming/
Khilyuk and Chilingar compare the total amount of co2 degassed from the Earth´s mantle in the last 4,5 billion years with the human output in the last 200 years and conclude that our contribution is “indistinguishable” compared to this. (They have many other strange claims about how humans cannot heat the planet directly and the same suggestions about ocean co2 sources as Spencer)
Anyone who has ever heard about the carbon cycle will readily see that this comparison makes no sense whatsoever, since all the co2 degassed billions of years ago has since completed several carbon cycles. This would be relevant only if all co2 had remained in the atmosphere since its formation.
There is no way these people could be ignorant of the fact that this is not the case. They have read the paper since they quote extensively from it. If this is not a politically motivated spreading of misinformation, then what other reasons do you see for them propagating this rubbish?
Loquor (17:11:58) :
“with respect to solar forcings: Are you referring to Solanki and others? Because as far as I remember, they did find problems, but none suggesting that solar forcing could in any way contribute with more than a minor fraction of the total forcing nonetheless.”
There are really two interesting developments in solar physics. The first is space based measurements show no significant change in TSI over the last 30 years. This has been the basis for the claim that solar effects cannot explain the current warming. However, the second thing that has happened is scientists like Svalgaard have looked at the solar proxies and concluded that the TSI has not varied much in the past either. The latter point is more troubling because there are significant climate shifts in the past that have been attributed to TSI because of a correlation between solar activity and the climate (e.g. the Maunder Minimum). This suggests that the sun’s influence on climate cannot be meaningfully measured by looking at the TSI.
You can find Svalgaard’s own words on the topic here: http://www.climateaudit.org/?p=2679#comment-205740
Later in the thread there is a link to an interesting paper by Julien Emile-Geay et. al. that suggests a solar-ENSO link. The paper is here: http://rainbow.ldeo.columbia.edu/~alexeyk/Papers/Emile-Geay_etal2007inpress.pdf
Now the above is nothing but interesting new research by respected scientists that may go nowhere. However, the fact that these issues are even being discussed today demonstrates that the IPCC cannot reasonably assume that the solar contribution to the current warming must be too small to be a factor. The correct answer is we do not know and a truly robust analysis would include these potential solar effects as part of ‘what-if’ scenarios.
The Mann hockey stick issue is a lot more muddled. I have read through the arguments and counter arguments and have come to the conclusion that any proxy study that includes bristle cone pines does not provide any useful insight into past temperatures.
Here is McIntyre’s discussion of Mann 2007 which addresses all of the arguments from the previous studies: http://www.climateaudit.org/?p=2421#more-2421
I will concede that the argument boils down to two competing scientific opinions regarding the usefulness of bristle cone pines as temperature proxies. In my opinion the weight of the scientific evidence falls rather heavily on the side of McIntyre. A recent study by PhD student at UA is the most recent paper that undermines the useful of BCPs as temperature proxies. See http://www.climateaudit.org/?p=2682
Now does Mann’s continued use of dubious proxies constitute dishonesty? I would say definitely yes if you want to claim the Micheals et. al. are dishonest because they refer to peer reviewed paper that appears to have been discredited.
I also think you are bit too critical when it come’s to Roy Spenser’s musings on this topic. In my job, I will frequently brainstorm by assuming that everything we know now is wrong and propose a 180 degree shift in thinking. I will then work through the problem and check for contradicting information and see if it can be delt with under the “new” paradigm. Often I end up validating the old paradigm because the 180 approach makes no sense. Other times I find flaws that need to be addressed but don’t invalidate the old paradigm. Once in a while, I will find the new paradigm makes a lot more sense. When I go through this kind of exercise I deliberately ignore facts that “I should already know” because the entire point of the exercise is to re-examine existing assumptions.
I hope Dr. Spenser will drop the topic and this blog post will serve as a useful public record of the counter arguments if other skeptics try to raise this canard again. This useful public record would not exist if Dr. Spenser had done his homework first. For that reason I am glad he did not.
quote And Julian, the water saving ability is exactly the feature of c4 plants that has to do with the co2 effectivity. Simply put, c3 plants have to leave their stomata open for a much longer time to absorb the same amount of co2 that a c4/CAM plants can absorb in a short time/at night. This causes greater respiration in c3 plants. Higher co2 levels will – in theory and ceteros paribus – give the c3 plants a competitive advantage and c4 plants a disadvantage. I will not try to make any guesses to what this will mean put together with water, sunlight nutrients etc (with respect to Liebigs law of minimum) under real-life conditions in a future world. I am just stating that there is as little empirical and theoretical foundation for predicting greening deserts and thriving plants as for predicting doom and gloom. unquote
Has anyone tried C4 at higher CO2 levels? C4 is a stress reaction and works better in drought and salt-elevated circumstances. There’s a chance that they will get better stress response from more CO2, as they’ll lose less water getting the required carbon. I have not seen it addressed as a response with actual trials. [Ah, I now read Raven’s earlier post — there you go. Green deserts, here we come.]
JF
Raven,
thank you for the links – Julien Emile-Geay is a man I have a lot of respect for, so i will read his paper in details when I get time. I do not pretend to understand solar physics in any details. I do, however, know that IPCC has a lot of contributors with a profound understanding of the subject like Lockwood, Lean and the likes, so I am sure that they will catch up on interesting new paradigms.
Regarding Mann and dishonesty , it seems like the jury is still out in this case of bristlecone pines, but let us assume you and Abaneh are right – they are not very reliable. This is then a recent development that Mann – grudgingly – will have to accept. I think a comparison with Svensmarks workwith respect to the Damon/ Laut and Lockwood/Frölich findings might be useful. Svensmark has quietly stepped back from many of his previous assertions while still maintaining that his theory might hold some (not very well specified) key to a very central issue, so far really without producing any evidence.
Is Svensmarks proceeding dishonest? My answer is a definite “no”. We all have a weak spot for our own theories and thoughts, and we only accept that something we really thought could be groundbreaking turns out to be merely wrong if the evidence is overwhelming. So far, I see clear indications that Mann may have been over-confident in his proxies and that Svensmark may well just waste his time (especially with respect to the present warming, which is Svensmark´s core), but I would not say that the evidence is yet overwhelming – in the sense that no reasonable counterarguments cannot be produced. So they are perhaps not following the best available evidence, but that is just normal practice for scientists with respect to their own conceived theories/procedures.
But none of this applies to the Michaels/Lindzen/Carter/Spencer and Khilyuk/Chilingar. Have you read the K&C paper? This is not the propagation of a new or a poorly supported but potentially interesting theory, it is simply sheer rubbish with mistakes so egregious that you wonder what the editorial board of the journal have been doing during the review process. For example, K&C claim that the entire energy consumption generated by humans could not heat the atmosphere by more than 0,01 C by direct heating – and who on earth have ever claimed that direct heating makes any contribution whatsoever to global warming? But tjis does not prevent Carter and Lindzen from quoting exactly this phrase in their critique of the Stern review cited above – they even emphasize this as a prime example for lampooning Stern for ignoring “sceptical science”.
While I do follow your logic about the usefulness of rethinking paradigms once in a while and ignoring things “you should know” in the process, this is hardly an example of such an exercise, is it?
As you show, the purpose of this exercise is to force yourself to take a critical look at the evidence and then only go on with the things where you have successfully identified flaws and holes in the standing paradigm which cannot be addressed by the current body of evidence. There is no way that all these people did not immediately identify the fallacies of K&C´s reasoning. And yet they still used their false arguments for producing a long authoritatively looking paper which had clear political motivation, and which they know will be propagated end recycled endlessly among people eager to believe that this is all a hoax or a socialist conspiracy – it already has been. So far I have seen none of those people try to recant their erroneous assertions. It is hard to avoid the conclusion that they do not really care about the scientific evidence, do not you think?
I agree that records of mistakes are indeed useful, but there are countless similar earlier records on exactly this shopworn argument that take less than a minute to find via Google. I find it difficult to accept this as an excuse for Spencers musings here – as I said, the basic facts should be known to any first year ecologist and surely to an experienced researcher with 30 years work in exactly this topic. I think that Spencer were indeed aware of the counterarguments but chose to write this up anyway. If this does not indicate an intent to blow smoke, then what reasons do you then see?
I don’t know if Dr. Spencer is still monitoring this thread, but, if he is, it would be interesting at this point to have him comment.