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BBC contrarian top 10

Filed under: — gavin @ 13 November 2007

There is an interesting, if predictable, piece up on the BBC website devoted to investigating whether there is any ‘consensus’ among the various contrarians on why climate change isn’t happening (or if it is, it isn’t caused by human activity or if it is why it won’t be important, or if it is important, why nothing can be done etc.). Bottom line? The only thing they appear to agree about is that nothing should be done, but they have a multitude of conflicting reasons why. Hmm…

The journalist, Richard Black, put together a top 10 list of sceptic arguments he gathered from emailing the 61 signers of a Canadian letter. While these aren’t any different in substance to the ones routinely debunked here (and here and here), this list comes with the imprimatur of Fred Singer – the godfather to the sceptic movement, and recent convert from the view that it’s been cooling since 1940 to the idea that global warming is now unstoppable. Thus these are the arguments (supposedly) that are the best that the contrarians have to put forward.

Alongside each of these talking points, is a counter-point from the mainstream (full disclosure, I helped Richard edit some of those). In truth though, I was a little disappointed at how lame their ‘top 10′ arguments were. In order, they are: false, a cherry pick, a red herring, false, false, false, a red herring, a red herring, false and a strawman. They even used the ‘grapes grew in medieval England’ meme that you’d think they’d have abandoned already given that more grapes are grown in England now than ever before (see here). Another commonplace untruth is the claim that water vapour is ’98% of the greenhouse effect’ – it’s just not.

So why do the contrarians still use arguments that are blatantly false? I think the most obvious reason is that they are simply not interested (as a whole) in providing a coherent counter story. If science has one overriding principle, it is that you should adjust your thinking in the light of new information and discoveries – the contrarians continued use of old, tired and discredited arguments demonstrates their divorce from the scientific process more clearly than any densely argued rebuttal.


397 Responses to “BBC contrarian top 10”

  1. 301
    Raplh Smythe says:

    David B Benson, thanks for the link. Cool stuff.

    Hank, you have gotten the opposite of what I’m saying (and this isn’t rhetorical). What person could possibly make any kind of coherent argument that speeding up burning fossil fuels would make things better? That’s silly.

    I’m saying focus on implementing policy and economic measures that cut pollution, which involves cutting the use of fossil fuels by conservation and stricter standards/increased efficiency, cleaning the output of what is still used, and replacing as much as possible with fuel cells, hybrid vehicles, electric vehicles, PV cells, wind turbines…

    I think it’s better to just focus on cutting pollution and let that take care of the anthro-GHG aspect of this combination issue, rather than discussing minutia like if CO2 radiative forcing is a little more than 50% of the anthro-GHG as a whole or not. Who cares. Discussing if the radiative forcing of nitrate aerosol is -.5 -.03 -.02 or -.22 does nothing towards reducing emissions. Who cares. Does sequestering CO2, regardless of how bad it is or not, reduce polution? Probably not. Does reducing fossil fuel usage reduce pollution and anthro-GHG at once, regardles of how bad CO2 is or not? Yes.

    Then the issue is framed in terms of reducing pollution by reducing emissions rather than contentious details.

    I believe framing it in terms of emissions and pollution would get more traction, and be a better way to compel action then going around in circles about what .25 means compared to .50 (or whatever)

    “Human activities—primarily burning of fossil fuels and changes in land cover—are modifying the concentration of atmospheric constituents or properties of the surface that absorb or scatter radiant energy.”

    That means the focus should be on lessening, stopping or reversing those aspects of burning fossil fuels and changes of land cover which result in perceived or likely detrimental effects to the concentration or properties, not quibbling over esoterics.

    My top detrimental of each category are pollution and deforestation.

  2. 302
    Rod B says:

    Jeeeeze. JCH, you inadvertantly (sic) left off another: “…The results suggest not all the large changes seen in Arctic climate in recent years are a result of long-term trends associated with global warming.” And as I said, this one doesn’t require a PhD to read. (Though I might be off in guessing NASA press releases and PR summaries are written for the general public.) You guys are just hell-bent to show that NASA did not write what they wrote. Amazing! Especially since it is at worst a teeny-tiny insignificant roadbump in the AGW debate.

    Hank says, “…Rod, Gavin and others are responding to the fake science claim from Fox News, not arguing with you.”

    I’m befuddled. Gavin and others answered my question(s) directly. What on earth is the problem??

  3. 303
    J.C.H. says:

    In the report the large changes not associated with AGW are large changes in water circulation. Arctic Ocean circulation is a large part of the Arctic climate.

    What additional large changes in the Arctic climate is the report attributing to variations in a decade-long time scales?

  4. 304
    Hank Roberts says:

    Raply asked:

    > Would fossil fuel usage that created another 100 ppmv of CO2
    > (along with all the rest of the positive and negative forcings)
    > result in more positive forcing on the net?

    Yes. Burning more fossil fuel will increase the committed warming.

    Wait for it: http://pubs.giss.nasa.gov/abstracts/inpress/Hansen_1.html

  5. 305
    Raplh Smythe says:

    Hank, that looks like a good paper. I’ll see if Dr. Hansen can make a compelling case for the first sentence, which seems a bit overstated, and I’m interested to see what he has to say about the subject in the last sentence. I certainly agree fossil fuels are the main driver of climate change and that we need to minimize whatever negative impacts they have.

    As far as your answer of yes, you seem to be saying that fossil fuel = CO2 and CO2 = warming after all is said and done, in the overall equation.

    I’m not saying you’re wrong about your opinion in that conclusion you’ve reached. What’s your estimate of when the next 100 happens and what the anomaly will be at that time in light of all the other factors in the process and the uncertainties involved?

  6. 306
    Steve Bloom says:

    Re #s 302/3: That “large changes” phrase was just the writer’s attempt to avoid the reader interest-killing alternative of using the term “Arctic Oscillation” right up front and then immediately having to define it, while also avoiding saying “circulation” for a third time in the first paragraph. Of course just saying “circulation” or “large changes” doesn’t define Arctic Oscillation very well either, thus the confusion. The fact that the bit disconnecting the sea ice trend from the AO was buried way down in the body of the release was no help, but as I implied in another comment (that doesn’t seem to have appeared yet) a responsible journalist will look for wrinkles like that before going with the story. In particular, a responsible journalist would wonder why “large changes” was used if reference was being made to the sea ice trend.

  7. 307
    Raplh Smythe says:

    Just so you know, my own ballpark on this (holding everything constant ratio-wise, % CO2 added per year, all non-C02 AGHG and O3 at the same rates, and predicting the future by the past) is a total of 800 ppmv and another +2.2 C within 33 years. That of course makes a lot of assumptions, which may or may not be warrented. Including the assumption my calculations are correct!

    So 100 is another +.53 C anomaly in about 8 years. It remains to be seen how correct the models are, what society and technology will do over the next 8 years, and how correct the assumptions have been.

    I still say focusing on anything other than reducing pollution as the goal and considering the methods to do so is rather spinning one’s wheels. But that’s just my opinion.

    Check it out in 2015.

  8. 308
    larry W says:

    I have not had time to read all the above posts, but find them very interesting. As an engineer I like to look at the overall picture first. Global warming is much preferred to cooling because it increases all the components necessary for life: water, carbon dioxide, and heat. With world population increasing this is very important. With laws of thermodynamics, as more people generate more heat, does it not take a temperture rise to get it to leave earth?
    Getting a little more specific: The IPCC graph on Global Mean Temperature since 1850 leaves me with one impression other than the long term upward slope. Namely, the period 1910 to 1945 has at least the same upward slope as the last 25 years yet this is not mentioned with any significance. A downward and flat cooling period followed 1945. The Hadley Centre global mean temperature has been quite flat for the last ten years and the ocean temperatures seem flat also. What does your model say about this when the news media says we have more rapid heating?
    I hear no media talk about how the Clean Air Act is being applied around the world and what it will do to warming. One researcher said if we applied removal of sulfur from all world fossil fuels we can expect global warming equal to that expected from carbon dioxide. We certainly know sulfur dioxide’s influence better that CO2 given the cooling experience in the 70′s and various volcanos.
    Gore’s glacier data failed to say that glaciers started receeding in the early 1800′s and have continued at about the same long term rate. Where did the heat come from to cause the early glacier melt? Now excessive ocean level rise being blamed on ice melting. The total polar ten year survey using all best availabe melt calculated an amount equal to about 10% of ocean level rise and about 2 inches from melt per hundred years. Again not what the media publishes.
    Why am I sceptical? I have not heard one word of this data getting to the general public and all I see is all the scare tactics being thrown out and the news papers calling carbon dioxide a pollutant.
    Your point has been made about CO2 now do something significant about it and direct your billions of research dollars to solving the few nuclear power problems that the public has been scared to death about. The world has over 600 nuclear plants moving toward construction while the US finally gave one the green light to move forward. If we had put all the dollars that our wars are costing into building nuclear power we would shortly be free of foriegn oil and terriorism would fade to nothing. Oil went from $40 to $10 when we had the last plant building surge.
    Lastly, if your global warming group is truely worried about warming and not just forcing a cut back on our life style then lets put more work on putting reflective compounds into the upper atmosphere. The studies I have read said the cost is reasonable.
    I have gone on long enough to explain why many of my professional friends have lost faith based on the garbage we get in the news.
    If our nation is forced into the very expensive renewable enery we will become a second rate nation with the life style of the poor getting worse. Our state has already mandated that 15% of all new electrical capacity be from renewable, yet most have made that decision on what they read in the papers. Coal plants that can give the lowest cost power are being force to drop plans even if it uses the very expensive gasification route.
    Thanks for your time and comments would be gladly accepted.

  9. 309
    Chuck Booth says:

    Re # 308 Larry W “I have gone on long enough to explain why many of my professional friends have lost faith based on the garbage we get in the news.”

    Then why not read what the scientific journals are saying (Science, Nature, Proc. of the Royal Society, Proc. of the NAS, etc), and the scientific organizations such as the NAS and the Royal Society, and the ICPP reports? They all have websites with free news updates, and some key journal articles are open access. Don’t rely on newspapers to filter the scientific news for you – they aren’t necessarily trying to mislead you, but their #1 objective is to sell newspapers.

  10. 310
    Hank Roberts says:

    Quickly, just one reader here, reply to Larry’s many questions:

    > have not had time to read
    The “start here” link at the top of the page and “History” link under Science are good starts.

    > world population
    Direct energy production (waste heat) from all human activity is tiny compared to the increase in heat trapped by increasing greenhouse gases. Numbers are available, someone will recall what to search on.

    > slopes
    http://scienceblogs.com/stoat/2007/05/the_significance_of_5_year_tre.php

    You’ll also find discussion of the variation; old dirty coal before 1970; Clean Air Act limiting aerosols from US coal plants.

    > media/Clean Air Act
    That is only a US law, not copied in China or India where the new coal burning is increasing. At that more southerly latitude, aerosol/solar chemistry differs. This decade, background CO2 is higher, committed heating is already built in that the new dirty plants don’t overcome. Coal produces sulfate, acid rain, as well.

    >Gore failed
    What’s your source for your information, now, on this? Tell us what your source is and why you consider it reliable, and we may be able to comment on whether it has been reported correctly in the media. Which glacier data do you refer to? Which “total polar ten year survey” do you refer to?

    > Why am I skeptical?
    Everyone is. That’s why we’re here, all of us. The true believers are elsewhere pounding the drums for whatever they consider unassailable truth. Well, some visit occasionally. But they never have references to check.

    > Reflective compounds
    Try the Search box at the top of the page

    > Our nation … our state … lowest cost

    Cost includes those downwind, thus Clean Air Act and the recent Supreme Court decision, if you’re in the USA. External costs are starting to be accounted for. This makes the free market work. It bothers those who were profiting by externalizing costs.

    > even if it uses … gasification
    Gasification isn’t the same as sequestration or even control of output.

    What did someone (stockholders? regulators?) “force to drop plans” specifically? Pointer to actual story?

  11. 311

    [[I’m not saying that the people writing here said that CO2 was the only variable. I’m saying it appears to me that in general it gets too much focus.]]

    No, it really doesn’t. The vast majority of global warming is due to increased CO2. If that increase had not happened, we would not be seeing significant global warming from about 1970 on.

  12. 312

    [[Lastly, if your global warming group is truely worried about warming and not just forcing a cut back on our life style then lets put more work on putting reflective compounds into the upper atmosphere.]]

    With unknown side effects? And allowing the oceans to die through continued acidification? I have a better idea — reduce CO2 output in the first place.

  13. 313
    Gary Moran says:

    Sorry if I’ve double posted, seemed to disappear:

    The hypothesis of AGW shouldn’t be couched in the words of certainty, and we should be careful of expensive policy decisions based on it. The evidence is primarily circumstantial: we are currently in a warming phase; while climate reconstructions favoured by RC show CWP to be unprecedented, other proxy studies show greater variability and there is a divergence problem between proxies and the current temperature series; paleoclimatology seems to show a reasonable split for the role of CO2 in the climate of the Phanerozoic; GCMs are useful tools in trying to understand what may be happening, but they are not reasonable evidence by themselves; surprisingly the underlying physics is far from certain, there seem to be multiple high level explanations of the atmospheric greenhouse effect, a reliance on a non physical concept termed “radiative balance”, and possible mis-applications of laws (e.g. Kirchhoff’s law of thermal radiation). The moderate (and I would guess predominate) sceptical view: that AGW is occuring, but that climate sensitivity will be at the low end of the spectrum, and will not be cataclysmic; is entirely reasonable.

    [Response: This is simply one fallacy after another. Current concerns about CO2 pre-date all proxy reconstructions and do not rely on anything being unprecedented. Please read - http://www.realclimate.org/index.php/archives/2007/08/the-co2-problem-in-6-easy-steps/ for a background on all this. - gavin]

  14. 314
    James says:

    Re #308: [Global warming is much preferred to cooling because it increases all the components necessary for life: water, carbon dioxide, and heat.]

    Actually that’s not so, if you consider all life. 3/4 of the Earth’s surface is water, and colder ocean waters are generally much more productive than tropical seas.

    Even on land, things aren’t nearly as simple as warmer=better. The Sahara is considerably warmer than the Yukon Delta, yet over the course of a year which do you think supports more life?

    Lastly, life tends to adapt to local conditions over the course of many thousands of years. Change those conditions quickly, in any way, and you’re going to disrupt the system.

  15. 315
    J.C.H. says:

    steve bloom, others,

    I’m a lay person, so I can easily get off course on this stuff. The author of the study seems to me to be talking about Arctic Ocean circulation as being something distinct from (but related to) AO, which I understand to be a measurement of atmospheric pressure. Reading around the net, it seems some are discussing AO and Arctic Ocean circulation as identical things. I think I understand the relationship between the two, but not if they are one in the same thing.

    Does the report negate the following, which is from the same university:

    “The Arctic Oscillation has been in a primarily moderate to high phase during the last decade or more, and the only way to reproduce this tendency in the oscillation using a numerical climate model is if you include the observed increase in greenhouse gases in the model. …” – http://uwnews.org/article.asp?articleID=7070

    I guess I’m wrong, but I don’t interpret Morison’s quote, which he limits to the wet part of the Arctic, which I take him to mean specifically the Arctic Ocean water (liquid – he was using, among other things, ocean-bottom sensors), as applying specifically to anything about the Arctic climate system that is either frozen or gaseous. Am I totally off base on this? If so, please help me a out a bit.

  16. 316
    Rod B says:

    re 306 (Steve): “…That “large changes” phrase was just the writer’s attempt to avoid the reader interest-killing alternative of using the term “Arctic Oscillation” ………. ”

    Which is what was explained to me a jillion posts ago, and what I accept, including the …..s above. I’m not going to skewer a writer for inadvertently screwing up an otherwise arcane technical nuance so as to make it readable. I’m just amused with the contortions and gyrations that others are going through to claim it was never written.

    I agree that journalists ought to verify stories, but it’s holding them up to the pristine ultimate level to say they should have bored into the body and between the lines and drawn their own expert conclusions to determine if the official “opening” statement was right or wrong. Seems like a unique and extreme standard. But I’m not really defending Fox. From their standpoint I don’t care.

  17. 317
    Raplh Smythe says:

    Actually Barton, the vast majority of what is going on is due to carbon dioxide, ozone, and the other AGHG from fossil fuels (aborbing more IR et al), the feedbacks of water vapor in the process, pollution from fossil fuels (increasing the albedo of the atmosphere, interacting with clouds, being deposited on ice and decreasing its albedo, and being deposited in the oceans), and the clearing of areas that don’t normally absorb much heat in the ground (grasslands, forests, jungles) into ones that do (cities, farmland, roads). These are not separate issues and it doesn’t help every treating them like they are.

    Laboratory results showing what CO2 does, or models showing its part in climate are not the entire story. I don’t think it’s helpful to pay any attention to it alone. What creates CO2 (or CH4 or…) creates pollution, why deal with one of the AGHG and ignore the rest of it? To the “average person” ‘reducing pollution’ is probably a much better argument than ‘reducing carbon dioxide’.

    1. Focusing on and/or bickering over the role of 100 ppmv is counter-productive. Emotional points carry more weight.
    2. Logic is almost always beaten by emotion or perception.
    3. The details (CH4 or whatever) distract from the issue (slowing/halting/reversing detrimental climate change).
    4. 100 ppmv = +.7 anomaly is too simplistic in any case.
    5. The IPCC recognizes particulates and land use changes are an important consideration in this. We should too, and change our focus.

    I suggest interested parties look here for more factors to deal with in the system:

    http://www.uwsp.edu/geo/faculty/ritter/geog101/textbook/atmosphere/
    http://lwf.ncdc.noaa.gov/oa/climate/gases.html
    http://www.met.tamu.edu/class/old_atmo629/Week7%20Feedback%20Mech.ppt
    http://www.grida.no/climate/ipcc_tar/wg1/127.htm
    http://www.grida.no/climate/ipcc_tar/wg1/160.htm
    http://modis.gsfc.nasa.gov/data/atbd/atbd_mod03.pdf

    Radiative Forcing of Climate Change
    http://www.grida.no/climate/ipcc_tar/wg1/212.htm

    Anthropogenic aerosols scatter and absorb short-wave and long-wave radiation, thereby perturbing the energy budget of the Earth/atmosphere system and exerting a direct radiative forcing.

    It ain’t just CO2. It’s all I’m saying.

  18. 318
    Hank Roberts says:

    Nobody thinks it’s just CO2.

    But we have to reduce CO2 regardless of climate because of ocean pH.

    Reducing CO2 is the “no regrets” strategy that helps everything else.
    There’s no way to reduce the other problems while leaving CO2 growing.

  19. 319
    Raplh Smythe says:

    Hank, for somebody that says CO2 isn’t the only issue, you seem to focus on it quite a bit.

    Not important. How do you reduce CO2? By cutting the things people do to create extra. What is that? Primarily by burning fossil fuels, which also creates pollution.

    Reducing the burning of fossil fuels reduces “the other problems” while keeping CO2 from growing.

    We can’t attack CO2 without attacking the cause, burning of fossil fuels. Are you going to phrase it in “reduce CO2″ or “cut pollution”, that’s the issue here. I don’t care which you use, as long as it’s the one that will influence people more.

    The issue isn’t what the acid/alkaline ratio of the oceans is, or how fast the 2.4% of the water in polar ice caps and glaciers on Earth is melting, or what 1000 extra ppbv of methane would do, or what .03 to .04 of carbon dioxide would do.

  20. 320
    Hank Roberts says:

    All those issues are of scientific concern. You want a discussion of framing and political tactics, I guess. I can’t help you here. Try anywhere in scienceblogs.com.

    “CO2 and other greenhouse gases” names the problem.
    http://www.pewclimate.org/global-warming-basics/

    Say “pollutants” and what’s the response?
    You can look this stuff up. For example

    http://www.google.com/search?q=tactics+for+controlling+pollution+by+greenhouse+gases

    You’ll start prolonged debates with arguments such as:
    pollutants aren’t legally controlled in their jurisdiction, or
    only new sources are subject to the laws and they’re grandfathered, or, well, this:
    http://news.independent.co.uk/world/americas/article3166414.ece

  21. 321
    Raplh Smythe says:

    Yes, Hank. Good stuff. But I wouldn’t dare of trying to even argue the political minefields of the sources you’ve sited (if there’s anything more dicey than climate change, it’s politics and religion). I know there are a lot of “contrarians” out there, as in the topic of this post! But I’m just saying the science part has become a detail in the political arena and that’s where everything needs to focus. No matter how difficult the game, it has to be played at this point, not standing there in the huddle debating the next play while the other team scores.

  22. 322
    J.C.H. says:

    “I’m just amused with the contortions and gyrations that others are going through to claim it was never written. …” – Rod B.

    Glad you were entertained.

    I had seen the report referred to on several blogs as proof global warming was not happening. There was a post from somebody talking about egg on the face, and gavin asked for a link, so I posted one. Prior to that moment, I didn’t know AO from BO.

    I have been reading about AO and ocean currents and ice movements and types of ice and ice extent, etc. all day and now understand what steve bloom is saying.

    I am curious if anybody has an opinion about the early AO indication and the bet.

  23. 323
    Hank Roberts says:

    Plenty of science yet to do. Example:
    http://www.pnas.org/cgi/content/extract/104/47/18353

  24. 324
    Frank Warner says:

    I’m a little confused about #7 on the list. The BBC says it’s irrelevant; this post says it’s a red herring; Al Gore made a big deal about it; an earlier post on RC supported Al Gore’s position.

    Recap: The Ice records show CO2 lags temperature in geological history. How does this make the case of future increases of CO2 causing temperature rise…or is it irrelevant?

  25. 325
    Tim McDermott says:

    re 308: Your point has been made about CO2 now do something significant about it and direct your billions of research dollars to solving the few nuclear power problems that the public has been scared to death about. (emphasis mine)

    It is always interesting to see where people think tax dollars are being spent. In five minutes with Google, I found that the FY 08 budgets for NASA earth sciences (which includes lots of non-climate stuff) is ~1.5B$. NOAA’s climate research is ~250M$. The entire NSF research budget is ~5B$.

    The DOE research budget (where non-military nuke research lives) is ~4B$.

    Nuclear energy has always had a pretty fat budget.

  26. 326
  27. 327

    #322, The bet is trivia. of only amusement value, its fun, like anything from Fox news is funny, but AGW subject is very serious. Anyone claiming the great melt of 2007 as just an anomaly, does not understand, perhaps not aware, of present Arctic Ocean ice coverage laced with thousands upon thousands of extra unfamiliar leads, amongst a huge area of thin ice. This is truly unknown territory, begging the question, how could this Ice cap ever return to normal? Certainly not in one year. Momentum is for melting, and some forget big time, the great melt occurred during a solar minima, it gets warmer from here folks.

    What I find intriguing is the apparent similarity with pressure systems, some call it AO, , but why would they be similar? Given tremendous temperature changes, it is fascinating that they are familiar, leaving to the very possible event , as happening right now again, “warmer winds from the North”, Arctic Oscillations at +20 C….

  28. 328

    Frank Warner (#324) wrote:

    I’m a little confused about #7 on the list. The BBC says it’s irrelevant; this post says it’s a red herring; Al Gore made a big deal about it; an earlier post on RC supported Al Gore’s position.

    Recap: The Ice records show CO2 lags temperature in geological history. How does this make the case of future increases of CO2 causing temperature rise…or is it irrelevant?

    Let’s take a look:

    7. A CARBON DIOXIDE RISE HAS ALWAYS COME AFTER A TEMPERATURE INCREASE NOT BEFORE

    Sceptic:
    Ice-cores dating back nearly one million years show a pattern of temperature and CO2 rise at roughly 100,000-year intervals. But the CO2 rise has always come after the temperature rise, not before, presumably as warmer temperatures have liberated the gas from oceans.

    Counter:
    This is largely true, but largely irrelevant. Ancient ice-cores do show CO2 rising after temperature by a few hundred years – a timescale associated with the ocean response to atmospheric changes mainly driven by wobbles in the Earth’s orbit. However, the situation today is dramatically different. The extra CO2 in the atmosphere (35% increase over pre-industrial levels) is from human emissions. Levels are higher than have been seen in 650,000 years of ice-core records, and are possibly higher than any time since three million years ago.

    Climate scepticism: The top 10
    Last Updated: Monday, 12 November 2007, 11:55 GMT
    http://news.bbc.co.uk/2/hi/in_depth/629/629/7074601.stm

    I think that particular response could have been clearer.

    The main point is that scientists do not argue that the relationship between temperature and atmospheric carbon dioxide is one-way but instead that there exists positive feedback between the temperature and atmospheric carbon dioxide.

    *

    Raise the temperature and the capacity of the ocean to absorb carbon dioxide or even hold onto the carbon dioxide which it has is diminished – like soda which becomes warm and loses its fizz. Raise the level of carbon dioxide and you diminish the rate at which thermal radiation is lost from the climate system so that the only way that the amount being radiated from the system can equal the amount entering the system is for the climate system to become warmer.

    When the temperature goes up first due to increased solar radiation, the consequent rising level of carbon dioxide will amplify the initial forcing, causing the temperatures to go still higher. When the carbon dioxide goes up first, the rising temperature will result in more carbon dioxide entering the atmosphere — pushing the temperatures up further. It doesn’t really matter where the initial forcing which disturbs the system comes from so much as the fact that there exists positive feedback once the system becomes disturbed — until the system finds the new equilibrium.

    *

    Moreover, there are times in the earth’s history in which a change in the level of carbon dioxide came first. Perhaps the best example is from 251 million years ago with the eruption of a siberian supervolcano. This raised the level of carbon dioxide in the atmosphere to around 3000 ppm, driving up the temperatures, and the result was the greatest extinction found in the paleoclimate record, wiping out perhaps 96% of all marine species and 70% of all land species.

    This is what is known as the Permian-Triassic Extinction, but sometimes it will simply be refered to as the Great Dying. For a while the dominant life form on land appears to have been fungus. Even among surviving species, generally more than 99% of their populations were wiped out. The biosphere didn’t really begin to recover for several million years.

    *

    Incidentally, you will notice that my explanation was a great deal longer than any of the explanations that were given in that piece. It can be difficult to explain things economically without sometimes losing important details.

  29. 329

    Frank Warner writes:

    [[The Ice records show CO2 lags temperature in geological history. How does this make the case of future increases of CO2 causing temperature rise…or is it irrelevant?]]

    In a natural deglaciation, temperature rises first and CO2 follows, but CO2, being a greenhouse gas, raises the temperature further. We are not seeing that now. For the past 200 years or so CO2 has led temperature. Two different processes are involved. In a natural deglaciation, the CO2 is coming primarily from the ocean. In the present warming, it’s coming primarily from fossil fuels.

    The fact that warming in the past has been natural does not mean it has to be natural now. That would be like saying, “people have died naturally for thousands of years, so this guy with the twenty bullet holes in him must have died naturally.”

  30. 330
    Rod B says:

    J.C.H., “….I had seen the report referred to on several blogs as proof global warming was not happening.”

    Therein lies the rub. Clearly many skeptics will not take my position but instead latch on to the molehill and make a mountain out of it. I understand that and the dilemma it causes. But I can’t help it; nor does it change what was written and what a very natural and common interpretation of the writing is. Instead of the contortions to change what was written, which makes you protagonists look silly, you should just claim it for what it is, tell the rabid set of us skeptics to stuff it, and then move on.

  31. 331
    dean says:

    Re #271-273

    While you’ve given me good resources to CO2 increases (which i do not question in any way), I still question why CO2 is the culprit this time when solar forcing seems a much more obvious candidate? Solar forcing tracks amazingly well over the last 200 years and if the earth is now just equalizing from the peak solar forcing of the 50s, it’s not tough at all to extrapolate that this is what’s causing the temperature rise.

    it certainly matches the 400 year trend much better than CO2 levels.

  32. 332
    Rod B says:

    Raplh (??) and Hank, this comment question might go against my overall position, but assuming Raplh’s contention is correct (all things ought to be addressed), doesn’t the practicality say to focus on CO2 since that’s what we seem to know more about its causes and fixes. Even as poor (IMO) as that is, isn’t it more than we know about methane, ozone, etc., at least in the GW scenario?

  33. 333
    Jim Eager says:

    Re Frank Warner @ 324: “The Ice records show CO2 lags temperature in geological history. How does this make the case of future increases of CO2 causing temperature rise…or is it irrelevant?”

    This is one of the most common questions/points raised by both skeptics and those just seeking to understand the mechanism of climate change alike.

    In the case of those who simply don’t yet understand that CO2 is a demonstrated greenhouse gas that can increase temperature both as a feedback and as a direct forcing, simple clear explanations like those given by Hank, Timothy and Barton should help clear up any misunderstanding, along with pointers to sources like Spencer Weart’s The Discovery of Global Warming @ http://www.aip.org/history/climate/index.html

    In the case of skeptics, however, the lag in the glacial record between temperature and CO2 is thrown out as a challenge, as if they were just playing a game of ‘gotcha’ and the lag negates all that we know about the physics of CO2 as a greenhouse gas. The fact that CO2 can act as a positive feedback and raise temperature further either never enters their mind, or is deliberately ignored, since it hardly supports their “gotcha.” The only thing one can do in that case is point out the error in their argument in hopes of preventing them from leading others astray.

  34. 334
    Jim Eager says:

    Re dean @ 331: “I still question why CO2 is the culprit this time when solar forcing seems a much more obvious candidate?”

    But it’s not, as has been discussed here many, many times in numerous posts and comment threads. See here:
    http://www.realclimate.org/index.php/archives/category/climate-science/sun-earth-connections/langswitch_lang/sp

  35. 335
    Paul says:

    re # 308 “Terriorism would fade to nothing” My Westie wants to know why SHE is being blamed now…

  36. 336

    dean (#331) wrote:

    Re #271-273 [Ray Ladbury and Hank Roberts]

    While you’ve given me good resources to CO2 increases (which i do not question in any way), I still question why CO2 is the culprit this time when solar forcing seems a much more obvious candidate? Solar forcing tracks amazingly well over the last 200 years and if the earth is now just equalizing from the peak solar forcing of the 50s, it’s not tough at all to extrapolate that this is what’s causing the temperature rise.

    it certainly matches the 400 year trend much better than CO2 levels.

    Actually, best estimates given by the Nasa GISS, it would appear that forcing due to well-mixed greenhouse gases have been a better match for temperature than solar forcing virtually every year since 1880 — with the one exception being that of 1881.

    Please see the graphs at:

    Forcings in GISS Climate Model
    http://data.giss.nasa.gov/modelforce

    … as well as the data at:

    Global Mean Effective Forcing (W/m2)
    http://data.giss.nasa.gov/modelforce/RadF.txt

    … and of course the technical papers which are linked to at the bottom of the first.

    *

    Well-mixed greenhouse gases would be principally carbon dioxide, methane and nitrous oxide — in that order. Nasa is of course omitting water vapor since it is a feedback which amplifies the effects of the well-mixed greenhouse gases, not a forcing. Finally, with the leveling off of methane and aerosols in recent years, carbon dioxide has been a better match for temperature since the late 1970s. Moreover, solar forcing has been essentially flat since the early 1950s.

    With the diminishing effects of reflective aerosols since the 1970s, one can most clearly see the weakness of the case for solar forcing being the primary determinant of the rise in temperature during the twentieth century. Since the 1970s, temperatures have accelerated. According to Tamino’s statistical analysis, even once one accounts for autocorrelation, the acceleration of global temperature in the past 15 years relative to the preceding 15 has been statistically significant.

    Now you have invoked latent warming, resulting from the increase in solar forcing prior to the 1950s. However, latent warming necessarily decelerates over time, falling off roughly as an exponential function of time, whereas the temperature increase has accelerated. As such, in logic, the latency of solar forcing cannot be invoked.

    *

    Finally, I appreciate the fact that you speak of “forcing” which belongs to a conceptual framework in which rather than attempting to reduce “the cause” of trends in temperature to a single factor, we recognize the existence of multiple causal factors. However, I am then puzzled by the fact that you then attempt to reduce “the cause” of trends in temperature to the single factor of solar forcing. I find this especially puzzling when you require trends in carbon dioxide over the past four centuries (thus including the 1600s) to be a better match for temperature before carbon dioxide can (in your view) be regarded as a causal factor.

    Industrialization became a factor only within the past two centuries, and became a major factor only with the consequent rise in the gobal population — which happened primarily during the twentieth century. The rise in the level of carbon dioxide, and its consequent dominance as the primary forcing driving the rise in global temperature was largely a function of this industrialization.

    PS

    If you want people to realize that you are responding to them, it might be good for you to respond a little sooner. Either that or actually include their names in the post itself. I strongly doubt that Ray Ladbury and Hank Roberts still remember the actual numbers of their posts — particularly after a little more than three days after the last of these posts.

  37. 337
    Chuck Booth says:

    This should be a more authoritative rebuttal of the AGW skeptics’ talking points:

    http://www.royalsoc.ac.uk/page.asp?id=6229

    Climate Change Controversies – A simple guide

    The Royal Society has produced this overview of the current state of scientific understanding of climate change to help non-experts better understand some of the debates in this complex area of science.

    This is not intended to provide exhaustive answers to every contentious argument that has been put forward by those who seek to distort and undermine the science of climate change and deny the seriousness of the potential consequences of global warming. Instead, the Society – as the UK’s national academy of science – responds here to eight key arguments that are currently in circulation by setting out, in simple terms, where the weight of scientific evidence lies…

    [If someone has already posted this link, I apologize for overlooking it]

  38. 338
    Ray Ladbury says:

    Dean, re: #331, If you had bothered to read Solanki’s work on solar forcing, you would have found that it is totally inadequate to explain the current warming trend.
    You also state: “Solar forcing tracks amazingly well over the last 200 years and if the earth is now just equalizing from the peak solar forcing of the 50s, it’s not tough at all to extrapolate that this is what’s causing the temperature rise.”
    Perhaps it is “not tough at all” if one is ignorant of the science or if one is willing to abandon conservation of energy. Since that is not the case for me, I find it quite tough indeed. Maybe you can help me. First, as Timothy has pointed out, insolation by itself is inadequate as a source of energy. Where did all the energy come from? Second, if Earth is “now just equalizing,” that would presume that all the energy now heating the atmosphere, surface and oceans was hidden somewhere for the last 50 years, and that this reservoir must now be cooling. Just where is this reservoir of heat? How did it remain undetected? Why did it take 50 years to “equalize”?
    Look, Dean, you can wave your hands until you levitate, or you can go actually work through the science and see that it is credible. If you have questions, the moderators (who are experts in the field) are good about answering them. If you don’t have the physics background for this, or if you don’t want to invest this much effort, then you are stuck at some point relying on authority. And if you are going to rely on authority, why in the hell would you take that of nonexperts when the experts are backed up by endorsements for every scientific professional society that has taken a position at all?

  39. 339
    dean says:

    Timothy (#337)

    I apologize for the slowness in posting my response. But sometimes life gets in the way of non-critical intellectual discussions (and since this is more of a hobby than a job for me, it is non-critical).

    I still disagree that GHG shows a better match for temperatures over the last few hundred years. While you mention the work Tamino did on GISS, if you use HadCRU data, your result is debatable. Specifically, the HadCRU data shows that the warming in the early 20th century was equal to what we’re seeing today. It’s commonly accepted here that GHG weren’t the cause of that warming period.

    It’s also accepted that aerosols caused the cooling from the 50s to the 70s.

    So what does this mean to me? well, i see the most likely scenario playing like this: the sun was relatively quiet throughout the 16th & early 17th centuries. The as it started to come out of it’s quiet phase, the temperature started to rise, albeit with a significant lag behind the solar forcing (up to 50 years). the solar forcing undulated for about 150 years at levels much lower than today’s value and concurrently, the earth warmed some and cooled some. Then in the first half of the 20th century, the sun got serious. That resulted in the steep temperature rise of the first half of the century.

    But then something happened… something man-made. Aerosols. This ‘artifically’ cooled the earth by reflecting away the solar heating (do i have that right? aerosols increase albedo?). but man figured out aerosols were a problem so man eliminated them and now the effect of a really active sun is once again being felt. hence, we see a major temperature rise even tho we don’t see the corresponding increase in solar output.

    Mayby this thought experiment will help understand my point: imagine that your oven is set to 150 degrees F. you take a pan of tap water (room temp of about 75 degrees) and put it in the oven. you start measuring the temperature of the water. after 5 minutes, you pull the pan out and put it in the freezer for 3 minutes. Then back into the oven. The resulting temperature vs time plot will look much like the 20th century temperature plot. It will start with a strong temperature rise (initial entry into the oven), followed by a slight decline (the freezer), followed by an even stronger temperature rise. It’s clear that the first entry didn’t get the water to equilibrium, so the second temperature rise ends at a higher point.

    Why does this not match the data?

  40. 340
    John Finn says:

    Gavin

    In response to an earlier post (#239) you claim that the G&T paper is “garbage”. I’ve now read the paper (twice) and checked out the ‘rebuttal’ links to which you refer. While it’s probably fair to say that some of the points made by G&T are open to debate I wouldn’t describe them as garbage. I am intrigued, though, by an issue raised in the paper. That is, the discrepancy between the average amount of solar energy (240 w/m2) received by the “non-greenhouse” earth and the properly calculated (rather than the assumed –18 deg C) effective temperature.

    The generally accepted effective temperature of 255K (-18 deg C) would, I suppose, be correct if the earth were a uniform flat disk but it is clearly not correct for a sphere. I always assumed any difference would be relatively small, but G&T show, by integrating temperatures over a static globe, that the effective temperature is –129 deg C. This does seem to raise some doubts about the greenhouse theory which says that the greenhouse effect is responsible for raising the average global temperature by 33 degrees.

    [Response: But this kind of thing is exactly why G&T is garbage. The standard calculation for the effective temperature explicitly takes into account the difference between the disk and the sphere (the factor of '4' which is the ratio of the different surface area). That is a global mean calculation of course, but the difference using a realistic distribution of surface temperature is very similar (that is actually what GCMs calculate). However, G&T's bizarre -129 comes from assuming a local instantaneous radiative balance at every point on the globe and then averaging the the resulting temperatures. Since half the planet is always dark, the local radiative temperature is 0 Kelvin (!) there - hardly a realistic calculation for the Earth. This neglects both the effects of thermal inertia and heat transports which are correctly integrated into the standard global mean calculation. Thus with much more mathematics than is necessary (they have a full derivation of the ratio of the surface areas of the sphere and disk - woo hoo), G&T manage to come up with a completely irrelevant calculation that is supposed to overturn all conventional thinking. That is simply garbage. - gavin]

  41. 341
    James says:

    Re #338: [And if you are going to rely on authority, why in the hell would you take that of nonexperts when the experts are backed up by endorsements for every scientific professional society that has taken a position at all?]

    Ray, I realize your question is rhetorical, but maybe some people need the answer spelled out: Because the experts aren’t giving them the answer they want :-)

  42. 342

    dean writes:

    [[ I still question why CO2 is the culprit this time when solar forcing seems a much more obvious candidate?]]

    Because solar forcing isn’t a much more obvious candidate. The present global warming can’t be caused by the sun. There are four major reasons for this.

    1. The solar constant has not increased appreciably for 50 years. We’ve been measuring it from satellites like Nimbus 6 and -7 and the Solar Maximum Mission.

    2. Increased sunlight would heat the stratosphere first. But we’re seeing stratospheric cooling. Partly this is due to ozone depletion, but the increase in greenhouse gases accounts for the rest of the effect.

    3. Increased sunlight would heat the equator more than the poles (Lambert’s cosine law). Instead we’re seeing polar amplification, which, again, was predicted by the climate models.

    4. Increased sunlight would raise daytime temperatures more than nighttime temperatures (obviously). But nighttime temperatures are increasing faster than daytime. This makes sense if increased atmospheric opacity from higher greenhouse gases is holding in heat at night.

  43. 343
    Jim Galasyn says:

    Thanks to Barton in 342 for his cogent and concise refutation of the solar forcing argument.

  44. 344
    Phil. Felton says:

    Re Gavin’s response to #340: The assumption that G&T make works fairly well for the sunlit surface of the moon (i.e a Lambertian profile) which has no atmosphere at all, and has an ~28 day rotation period. Mars with it’s much thinner atmosphere doesn’t have a Lambertian profile.
    BRIGHTNESS TEMPERATURES OF THE LUNAR SURFACE: S. L. Lawson and B. M. Jakosky, Lunar and Planetary Science XXX

    [Response: Like I said, relevance to Earth = 0. - gavin]

  45. 345
    Hank Roberts says:

    Hey, speaking of experts not giving the answers they want, the inimitable Benny Peiser just featured this in his CCNet email:

    “Craig Loehle has published a study in [Energy & Environment] indicating that trees rings are not reliable for determining past temperatures. Loehle focused on the Medieval Warm Period (MWP) (1000 – 1400) which is not shown in tree rings….”

    Yep. We know it happened, so, since the trees didn’t record it, that proves the tree rings are wrong.

    Oy. Another E&E headbanger.

  46. 346
    Ralph Smythe says:

    Rod B, #332, yes. I can’t even spell my own name correctly, why would anyone listen to me! :)

    Seriously though, not accusing anyone of focusing on CO2, but overall, it is unimportant to the discussion, in and of itself. A simplistic statement like “Rising CO2 levels since the start of the industrial era is causing a dangerous rise in average temperatures.” makes most folks go glassy eyed, I’d think. You have to know your audience. If somebody knows that CO2 is half the AGHG component, and that the cause of AGHG is fossil fuels, they might wonder why we’re not talking about reducing the burning of fossil fuels in the context of all AGHG and pollution instead of one of the AGHG. (And don’t forget land use changes.)

    Does any person not familiar with either the science or the contentiousness of climate change have their emotional buttons pushed by phrasing it in terms of carbon dioxide? Those that take a look deeper into this might question why .0003 to .0004 (.0000008 a year) of CO2 is important, if a 5.6 millidegrees C a year is a big deal, if one causes the other, or if the current trend will continue. I’m a proponent of “what if” and I certainly think these are issues at least to consider. My entire point, consider what conclusions that others not well involved might come to.

    I’m not arguing these things are not important, or asking about the science. I’m questioning how the issue is put forth.

    So, no, no matter how much we know about how CO2 acts, regardless if in practice, theory, models, or laboratory experiements, it shouldn’t be either the focus or even a topic. If the cause/effect is “CO2/temperature” then the more important relationship is “fossil fuels/CO2″. Or more accurately, “fossil fuels = AGHG + pollution”, or “fossil fuels + land-use changes = warming”.

  47. 347
    Tim McDermott says:

    Ralph (346),

    You seem to be arguing in circles, and not very rigorous circles at that. You don’t want AGW to be presented as a CO2 problem, but as a fossil fuel (and a some other things) problem. The trouble with your approach is that you have factored out two sources of CO2 and want to feature them as the causes of AGW. Land use is part of AGW because when we convert forest to farmland, the CO2 that the forest held in the soil gets released. You forgot cement production, which is a huge source of CO2. As we reduce the release of fossil carbon, most of the other GHGs are going to be reduced as well.

    And I think that I don’t agree with you that “fossil fuels” is less eye-glazing than “carbon dioxide.” The reason people’s eyes glaze over is they think the entire subject is unimportant, and dull. Even high school drop-outs will pay attention to discussions of CO2 when they start to understand that it threatens their children and grandchildren. The entire denialist community is dedicated to putting that understanding off as long as possible.

  48. 348
    dean says:

    Re 342

    Point by point…

    1. so what. If we weren’t at thermal equilibrium due to solar forcing in 1950, then we had not reached the temperature the sun was trying to bake us to. After the rise in the 1910-1945, the sun didn’t shut off. so the temperature should have stabilized at a new temperature (with the appropriate lag due to inertia of the system). but it didn’t. It cooled. Why? because the aerosols didn’t allow the energy from the sun to be absorbed. But man realized that aerosols were pollutants so we removed them. now we have an earth that’s returning to equilibrium. But it’s not the temperature in the 50s, its higher because we never reached equilibrium from the early 20th century solar forcing.

    Tim (in post 336) said that the latent heat drops off over time. I agree. but where this is a problem is with the temperature data between 1940 and 1950. The solar forcing that drove temperature up in the early century continued but the temperature suddenly dropped. why? because of aerosols. this pushed the earth farther from the equilibrium temperature and therefore the speed of rise increased once the aerosols were removed (which, by the way, was over time and not instantaneous)

    2. let me think about this one…

    3. But what doesn’t match here is that the poles (plural) aren’t warming. Only the north pole is. And the fabled “northwest passage” has been open before only to close back. there is nothing new in what we’re seeing. It’s all happened before (in recent recorded history) and most likely will happen again. The north pole warming and the south pole not warming goes against the climatic models, doesn’t it? not only that, none of the models predicted the massive melt-off this year. So something other than what’s in the models caused it (or if it’s in the models, then it’s not accurately modeled).

    4. But aren’t there questions as to the accuracy of that data? specifically, the weather station locations in urban areas (and don’t try to tell me that cities aren’t heat islands… ok, you can try, but i will not believe that because it just doesn’t make sense … I’ve leaned up against enough buildings after the sun’s set only to feel the bricks still radiating heat).

  49. 349
    Ray Ladbury says:

    Ralph Smythe, How would you suggest the argument be couched if not in terms of the sound science? Look, cheap fuels have distorted the global economy to an absolutely absurd degree. Here in Maryland, I can buy tropical fruits like durian, pineapple, mango and papaya (not exactly compact) more cheaply than I can buy locally produced apples and pears! That would argue that there are hidden costs not being paid by the consumer. Do you expect people to rally around such an economic argument? All I can say is that if humans are too stupid to understand the science, they’d better get a helluva lot smarter quickly.

  50. 350

    dean (#339) wrote:

    Timothy (#336)

    I apologize for the slowness in posting my response. But sometimes life gets in the way of non-critical intellectual discussions (and since this is more of a hobby than a job for me, it is non-critical).

    I still disagree that GHG shows a better match for temperatures over the last few hundred years.

    As I pointed out (336) it is invalid to expect CO2 to be more closely correlated with global temperature than solar variability prior to the industrial revolution. You may be attempting to reduce the trends in temperature to either solar variability and aerosols or carbon dioxide, but climatologists acknowledge the existence of several forcings — and with the cummulative effects of industialization, prior to 1880, solar variability tended to be a greater forcing than greenhouse gases, but not the only forcing. Relative to 1880, the only year in which solar variability was a greater forcing than greenhouse gases was 1881.

    dean (#339) wrote:

    While you mention the work Tamino did on GISS, if you use HadCRU data, your result is debatable. Specifically, the HadCRU data shows that the warming in the early 20th century was equal to what we’re seeing today.

    If you use HadCRU then the past fifteen haven’t shown a noticable increase. However, HadCRU specifically omits the arctic. GISS does not. As such, GISS is a more accurate assessment of the global average temperature — if one is specifically looking for the global average.

    dean (#339) wrote:

    It’s commonly accepted here that GHG weren’t the cause of that warming period.

    Actually it is commonly accepted that carbon dioxide wasn’t the main driver of the earlier warming period. Solar variability was stronger in the earlier half of the twentieth century than carbon dioxide. However, greenhouse gasses (or if you wish, simply carbon dioxide and methane taken together) had a greater forcing than solar variability. And according to the GISS data that I supplied you with in 336, they have been since 1882 relative to 1880 — as I indicated earlier.

    dean (#339) wrote:

    It’s also accepted that aerosols caused the cooling from the 50s to the 70s.

    Actually there were only six years of statistically significant global cooling from 1945-1951.

    Please see:

    Hemispheres
    August 17, 2007
    http://tamino.wordpress.com/2007/08/17/hemispheres

    dean (#339) wrote:

    So what does this mean to me? well, i see the most likely scenario playing like this: the sun was relatively quiet throughout the 16th & early 17th centuries. The as it started to come out of it’s quiet phase, the temperature started to rise, albeit with a significant lag behind the solar forcing (up to 50 years). the solar forcing undulated for about 150 years at levels much lower than today’s value and concurrently, the earth warmed some and cooled some. Then in the first half of the 20th century, the sun got serious. That resulted in the steep temperature rise of the first half of the century.

    There would be no lag of 50 years. As I have stated in 336, latent warming is strongest at the time of the increase in forcing and declines after that asymptotically over time — roughly as an exponential function of time.

    dean (#339) wrote:

    But then something happened… something man-made. Aerosols. This ‘artifically’ cooled the earth by reflecting away the solar heating (do i have that right? aerosols increase albedo?). but man figured out aerosols were a problem so man eliminated them and now the effect of a really active sun is once again being felt. hence, we see a major temperature rise even tho we don’t see the corresponding increase in solar output.

    In essence, reflective aerosols increase the albedo, but normally I believe the two are distinguished for conceptual reasons.

    dean (#339) wrote:

    Mayby this thought experiment will help understand my point: imagine that your oven is set to 150 degrees F. you take a pan of tap water (room temp of about 75 degrees) and put it in the oven. you start measuring the temperature of the water. after 5 minutes, you pull the pan out and put it in the freezer for 3 minutes. Then back into the oven. The resulting temperature vs time plot will look much like the 20th century temperature plot. It will start with a strong temperature rise (initial entry into the oven), followed by a slight decline (the freezer), followed by an even stronger temperature rise. It’s clear that the first entry didn’t get the water to equilibrium, so the second temperature rise ends at a higher point.

    Why does this not match the data?

    Offhand I can think of six reasons…

    First, we know that without the greenhouse effect, the average temperature of the earth would be -18 C rather than 15 C as a matter of simple physics. Clearly the greenhouse effect exists. As such, your single factor analysis (or two-factor, since you admit the role of reflective aerosols) is simply invalid.

    Second, the reason why we conclude that carbon dioxide is the primary forcing in the recent rise in temperature isn’t simply one of correlation. We know from spectral analysis that it absorbs and emits thermal radiation. We know its distribution in the atmosopheric column.

    We can measure it’s emissions at different altitudes. We can image those emissions from satellites at a variety of altitudes, measure it from planes, balloons and the surface. We have spectral measurements of atmospheric constituents at over a million different wavelengths. As such, the forcing due to carbon dioxide is well-known. We can do the same with solar variability, and while the exact effects of aerosols are more uncertain given their diversity and distribution, no such difficulties exist in the case of solar variability or carbon dioxide.

    As such, for the forcings due to solar variability and carbon dioxide are given with considerable accuracy by the GISS data I referred you to:

    http://data.giss.nasa.gov/modelforce/RadF.txt

    In watts per square meter, forcing due to well-mixed greenhouse gasses relative to 1880 was 1.6053 in 1978 and was 2.7487 in 2003. Given the leveling off of methane, the good majority of the difference between the two years is carbon dioxide. Forcing due to solar variability relative to 1880 was 0.2232 in 1978 and was 0.2233 in 2003. Not much of a difference between the two years, is there? Clearly, relative to 1880, the increase in forcing due to well-mixed greenhouse gasses (principally carbon dioxide and methane) has exceeded that of solar variability.

    Third, there is the fact that with statistical analysis, we can directly measure the greenhouse effect of water vapor and the fact that above 85 F in the tropics, and moreover, showe that there exists a super greenhouse under clear sky conditions where downwelling thermal radiation due to water vapor increases more rapidly than upwelling thermal radiation relative to temperature.

    I quote:

    At sea surface temperatures (SSTs) larger than 300 Kelvin, the clear sky water vapor greenhouse effect was found to increase with SST at a rate of 13 to 15 watts per square meter per Kelvin. Satellite measurements of infrared radiances and SSTs indicate that almost 52 percent of the tropical oceans between 20 N and 20 S are affected during all seasons….

    Satellite studies (8–10) have found that for clear skies and SSTs above 298 K, the spatial variation of Ga with SST, dGa/d(SST), exceeds the rate of increase of sea surface emission, ds(SST)4/d(SST) = 4σ(SST)3. For a tropical SST of 300 K, 4σ(SST)3 ~ 6.1 W m-2 K-1. This effect, termed the “super greenhouse effect” (11), occurs in both hemispheres during all seasons. It is also observed for interannual variations of Ga with SST during the El Nino in the tropical Pacific (12). Observations in the tropical Atlantic ocean (11) show that the clear sky downwelling infrared flux incident on the surface (Fa-) also increases faster than the surface emission with increasing SST. The net result is further warming of the surface, which in turn induces additional heating of the atmosphere column above.

    Direct radiometric observations of the water vapor greenhouse effect over the equatorial Pacific Ocean
    F.P.J. Valero, W.D. Collins, P. Pilewskie, A. Bucholtz, and P.J. Flatau
    Science, 274(5307), 1773-1776, 21 March 1997

    If one admits the existence of a greenhouse effect due to water vapor, one must admit a greenhouse effect due to carbon dioxide since the physical principles involved are the same — and the actual spectra themselves are virtually derivable from quantum mechanics. And given spectral analysis of carbon dioxide, we know that as you increase the levels of carbon dioxide, you increase the downwelling thermal radiation.

    Fourth, there is the diurnal temperature difference which has been on the whole decreasing roughly since 1950. This cannot be explained by solar variability. It can be explained by the diminished ability of the climate system to lose energy by means of thermal radiation.

    Please see:

    http://img37.picoodle.com/img/img37/5/11/23/timothychase/f_diurnalzugsm_a6bddcb.jpg

    Fifth, given an enhanced greenhouse effect, we would expect the trend in summer temperatures to be greater than the trend in winter temperatures. With the enhanced greenhouse effect we expect the opposite. The trend in winter temperatures has been greater over the twentieth century.

    Sixth, increased solar variability would result in the warming of the stratosphere. Given the greenhouse effect we would expect the stratosphere to have a cooling trend. The latter is the case.

    Please see:
    HadAT: globally gridded radiosonde temperature anomalies from 1958 to present
    http://hadobs.metoffice.com/hadat/

    … and especially:

    Frequently used HadAT graphics
    http://hadobs.metoffice.com/hadat/images.html

    I hope this helps…


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