RealClimate article on the same
Climate models appear to be missing an atmospheric ingredient, a new study suggests. December's issue of the International Journal of Climatology from the Royal Meteorlogical Society contains a study of computer models used in climate forecasting. The study is by joint authors Douglass, Christy, Pearson, and Singer - of whom …
Sadly for Douglass et al, and for Anton Wylie, the paper was demolished within a couple of days of being published, and two weeks before The Register reported on it. The paper's authors make several significant mistakes, the key one being introducing an invalid divisor for the standard error of the models, which falsely narrows the confidence intervals around the models' predictions. From there, the claim that reality falls outside the models' predictions, collapses.
There's more discussion by climate scientists of the paper, at: http://www.realclimate.org/index.php/archives/2007/12/tropical-troposphere-trends/
So I don't think the BBC will be updating its page, as its statement is accurate: Within the uncertainties of the data, there is no discrepancy. The models have been successfully tested, and anthropogenic global warming is, regrettably, still very much with us. Climate science is indeed far from over, but the question of whether there is man-made global warming has been resolved in the positive, with overwhelming scientific evidence.
Don't panic, someone will be along soon to explain that the science is settled, and we should do everything we can to delay impending disaster, even if we don't quite know all the details yet. Anyway, the glaciers agree with the models, and we wouldn't want the polar bears to starve.
IPCC is a political forum, they don't give a damn about science as far as it gives results, no matter how wrong, that suits them.
I'll bet 10 to one that IPCC won't change their mind about global warming for any reason, it wouldn't be politically suitable.
(Last meeting was in Bali, where everybody and their frends flew, there's _their real opinion_ about global warming.)
None of the existing climate models take into account the effect of water vapor on any level --simply because there is no way of knowing the water vapor content around every square inch of the planet. Instead, the models were created to corroborate the postulate (that mankind is inducing Global Warming) rather than disprove it, as is done within the scientific method routinely. That's why you continually hear about a "consensus" with respect to the conclusion and not proof. Of course, the last few instances of scientific consensus didn't work out so well - the planet isn't flat and the sun doesn't revolve around the Earth. A scientific consensus is simply a euphemism for "guesswork." Still, one should never let the facts get in the way of a strongly felt opinion...
The paper by Douglass, Pearson, Singer and Christy was recently analyzed at Real Climate, a blog run by climatologists including Michael Mann (a paleoclimatologist who is known for the original hockey stick diagram) and Gavin Schmidt (who worked on the most recent global climate model for NASA GISS). The conclusion that the authors arrive at, namely, that greenhouse gases are not what is primarily responsible for current warming -- is entirely untenable -- even if one were to find that the rest of their paper were largely or entirely correct. The reason being? We have a great deal of evidence that global warming is being caused by greenhouse gases.
For example, they increase the opacity of the atmosphere to infrared radiation, raising the temperature at the surface while reducing the amount of thermal radiation which reaches the stratosphere, hence cooling the stratosphere. Increased solar radiation would raise the temperature both at the surface and in the stratosphere. Likewise, warming will be greater at night and during the winter under an enhanced greenhouse effect as night and winter are more dependent upon the process of thermal radiation given increased atmospheric stability and thus reduced heat loss due to convection. All of these effects have been measured and are individually quite difficult to explain without reference to greenhouse gases.
Furthermore, our understanding of the role of greenhouse gases in warming the climate is built upon a solid foundation of physics, particularly radiation transfer theory, and more fundamentally, quantum mechanics. We can virtually derive their absorption spectra from the first principles of the latter. We can observe the thermal radiation which they give off at different altitudes at different parts of the spectra by means of satellites capable of watching well over two thousand spectral channels. We can measure the backradiation with which they heat the surface at the surface itself. We can even image the infrared emissions of carbon dioxide as it drifts away from the heavily populated west and east coasts of the United States at an altitude of 8 km -- because of the increase in the opacity of the atmosphere to infrared radiation given the higher CO2 concentrations.
At best, assuming the paper was otherwise flawless, the only conclusion which the authors might have right to derive would be that some of the details regarding the modeling of the tropical troposphere -- perhaps involving moist air convection -- require more work. We might conclude that one has to increase the model resolution in order to properly capture the process of convection at work, perhaps. However, as it is, the paper was deeply flawed.
They did not properly take into account model uncertainty -- and they completely omitted any analysis of the observational uncertainties inherent in the radiosonde product they used for validating the models. But what is worse is that is that they used a version of that product that was out of date. They used RAOBCORE v1.2, whereas the most recent version is 1.4. By simply using the more updated version of RAOBCORE and two standard deviation ensemble model uncertainty, the RAOBCORE product's curve for the tropics is well within the envelope of uncertainty associated with the models. And in fact, this is essentially what was concluded by a far better paper earlier this year:
Thorne, et al (2007), Tropical vertical temperature trends: A real discrepancy?, Geophys. Res. Lett., 34, L16702
For the Real Climate review of the paper by Douglass et al on the tropics, please see:
Tropical tropospheric trends
12 Dec 2007
With regard to the discovery of the twilight zone around clouds, I personally find this exciting. Clouds and aerosols are the two largest sources of uncertainty left in the models -- and I suspect that it will lead to considerable improvements in regional modeling. However, readers should keep in mind the fact that clouds have both an albedo effect and a greenhouse effect associated with them, and these two effects largely cancel one-another out -- with the sign of the net, residual effect being largely dependent upon the altitude and thickness of the clouds. However, as of yet, Real Climate has not done a piece on this particular development. I am hopeful that they might remedy this at some point in the weeks to come.
The AGW supporters must be seriously worried.
"Real Climate has not done a piece on this particular development."
Yet it has - the "Real Climate" blog gets three links in the first half dozen posts. Have these Global Warming bloggers been waiting up all night - in their pyjamas - simply to whack any media organisation that reports Douglass et al?
That seems to be the advice from the Hockey Stick site, which urges its supporters:
"Once more unto the breach, dear friends, once more!"
Comparing this article and "Real Climate" is most illuminating. There's much hand-waving and prevarication at "Real Climate", but no substantial rebuttal of Douglass' main findings, ably pointed out here by Mr Wylie, that the data produced by the 22 atmospheric models only works at sea level.
Bill O'Brien is correct: this is guesswork fed into a spreadsheet. What comes out is ... guesswork in Excel format.
oh, very well said sir!
I'd like to bet that Galileo Galilei is a very grumpy old man up in heaven seeing that the intervening 400 years hasn't changed the lemming like nature** of scientific 'opinion' . . . which when I was first undertaking formal science learning in early 1970's 'knew' that we would run out of oil by 1995
(and yes, I agree burning oil is a bad use of a limited resource - but that's not my point)
OK so now we have 'computer models' to prop up the argument here . . well I've done a lot of modelling over the years on areas a darn sight less complex than the atmosphere & I wouldn't trust a computer model to predict my supermarket shopping list let alone global warming.
A final thought, just try getting a research grant nowadays in the UK if your study doesn't positively mention 'green' issues in a major way - scientific research? pah! not in the UK as it's a POLITICAL ISSUE now (not because the politicians understand or care about the issues, just 'cos they have to appear to so they can fly off to Bali for a nice jolly)
hmm, re-read my ramblings above . . . think I have read too many posts from aManFromMars . . . must be infectious?
PS **OK, OK, before the flames start I know lemmings don't do that . . . but heck it's Christmas so allow me some small Disney inventions in the odd post here or there huh ?
was the big threat in the 1970's. Some of the same profs involved as today. The real threat appears to be no change, as that would give them nothing to publish about.
Sir, you missed the original scientific prediction that London will be three feet deep in horse shit by the 1900s. This could explain why our public transport is always running late since they have to plow through more than that stuff (in 2007)....
And then there was the Great Malthusian Theory that everyone will starve to death before the end of the 20th century.......
Now eat up your vegetables !! Poor children are starving to death everywhere outside London. It's only thanks to that thick layer of horse shit that we have such nice veggies to eat !!
Have you read the bios of the authors? The SEPP and S. Fred Singer in particular, is a longstanding, highly political critic of global warming. Skepticism is vital to science. In view of the authors' backgrounds, we should not forget to also subject their conclusions to a healthy dose of skepticism.
Since the Douglas et al. paper has been available since the 10th of December and www.realclimate.org analysis was published on the 12th of December only a fool would say that "these Global Warming bloggers been waiting up all night - in their pyjamas - simply to whack any media organisation that reports Douglass et al?" The realclimate analysis DOCUMENTS clear errors and deliberate misuse of data by Douglass et al. Considering the authors record of accuracy particularly Singer I wonder if they did any research at all. Singer did an analysis of the Kuwait oil fires. His "calculations showed that the smoke would go to an altitude of about 3,000 feet and then be rained out after about three to five days and thus the lifetime of the smoke would be limited." From direct observations we now know that smoke from the Kuwait Oil Fires dominated the weather pattern throughout the Persian Gulf and surrounding region during 1991, and that lower atmospheric wind blew the smoke along the eastern half of the Arabian Peninsula, and cities like Dhahran, Riyadh and Bahrain experienced days with smoke filled skies and carbon fallout.."
None of the climate models work for known intervals. There isn't one of them that will try to model the last 10,000 years.
If they can't model the climate we already know happened, how can they model what will happen?
I'm still waiting for RAOBCORE v1.6 which will PROVE that aliens are controlling our atmosphere...... until they come out with v1.8 of course.
Since we need more aerosols to cool us down, why should we put out forest fires. Al Gore should encourage the increase of particulate matter in the form of forest fires and wood burning fireplaces. That would help us better balance the climate, wouldn't it?
I mean Al needs to do more to offset his mansion he has with its electric meter taking off.
Oh, here I am in sunny Southern California, but I rember that the Rose parade was rained upon a few years ago for the first time in a bunch of years, so something is happening. Cooling, warming, man caused, natural, take your pick. The "science" is there somewhere to support it.
For example, F=MA. But there may be a point where M will turn around and slap you. That point is typically unknown.
For the climate models, we just don't know all the chemical and biological responses that may be triggered off. They're just as likely to be negative feedback as positive. We just don't know. Those that claim their models are accurate are fooling themselves. Why are they up to Rev. 17 if they're not a work-in-progress?
Science ~IS~ skepticism. Those that accuse people of being 'climate skeptics' are actually taking on the tone of religion. Of course a good scientist is a skeptic. Every good scientist should always be open to the next theory.
For the record, I'm all in favour of energy efficiency, alternate energy systems, and advance technology. Which puts me well ahead of the curve. But I remain skeptical, especially when the environmentals have become a religion. Such an attitude could well kill us well before global warming does.
It seems the consensus with this study is that it was poorly done, but it does sort of touch on another related issue of "global dimming".
It's a rather interesting topic, and one which was afforded an interesting opportunity for study shortly after all US planes were grounded on 9/11. Ironically, the very industrial emissions we put out that are apparently contributing to global climate change are also in some ways partially protecting us from the full effect. If that's the case, and climate models aren't taking that into account, it would explain why the models show the temperature as rising faster than it is in reality.
More AGW bovine flatuance. Model verification requires the model to reproduce observed climate before the model is used in experiments. The models used in the IPCC report model past climate very well. More evidence that the oil/gas industry dis-information campaign is working
And what a depressingly sad comment about food supply. With 6 billion inhabitants we're running out of productive land, e.g. 'Global food crisis looms as climate change and fuel shortages bite - http://www.guardian.co.uk/environment/2007/nov/03/food.climatechange'. Already we're using almost 80% of land that could effectively be productive so where is the food for the projected extra 3 billion coming from.
Just because you can wander into Tescos to buy food to gorge yourself doesn't mean we're not approaching a global food crisis (I'm assuming you don;t live in the Sudan because you'd understand the impact of Malthus' ideas already).
"There is an enormous ongoing effort to find errors in the observations that would reduce the disagreement with the models. [Shouldn't that be the other way round? - naive ed.]"
Dear naive Editor, it should be both -- it's an iterative process, and it applies to all rational knowledge (or do you think models are just fancy math in a computer?). That said, "reality" (observations) should always be given more weight, me thinks.
Under the subject of "Co-ordinated Real Climate spam?", Anonymous Coward writes:
"The AGW supporters must be seriously worried.
"'Real Climate has not done a piece on this particular development.'
"Yet it has - the 'Real Climate' blog gets three links in the first half dozen posts..."
I was refering to the subject of the twilight zone of clouds, not the tropical troposphere. It helps to read the sentence immediately preceding that one in the same paragraph.
"Have these Global Warming bloggers been waiting up all night - in their pyjamas - simply to whack any media organisation that reports Douglass et al?"
Nice ad hominem.
Real Climate goes quiet from about 4:00 to 12:00 GMT, give or take. I myself scan the news periodically throughout the day, just looking for new stories or new news on old stories.
For example, there is the thinning of the Arctic ice that, best estimate, will be gone during the summers by 2013 or earlier even though the models were projecting something more like 2050 or perhaps well into the 2100s. They seem to have underestimated some of the positive feedbacks, most particularly oceanic advection -- due to the low resolution of the models.
Then there is the increased saturation of various carbon sinks where for example parts of the major oceans including the Southern Ocean are proving less able to absorb our carbon emissions, although another major sink which is becoming less effective includes plants, at least during the warmer, drier years. Then there is the record melt in Greenland, news from the Antarctic Peninsula (both Greenland and Antarctica are losing mass now -- with the trend in Antarctica having been reversed within the past few years), etc.
Anyway, climate news has been a little slow with the holiday season, and this post at the Register came up -- so I thought I would check it out.
Anyway, I suspect you are right about spam being involved -- you simply misidentified the culprits and the intended targets. Every one of the authors is closely associated with at least one organization that is receiving funding from Exxon. Singer, Douglass and Christy belong to the Heartland institute -- which has received well over half a million US dollars within the past decade, for example. Singer is actually associated with thirteen organizations that have received funding from Exxon. Pearson is the odd man out, as he belongs to only the Atlas Economic Research Foundation -- brainchild of someone fond of Ayn Rand's "Atlas Shrugged," no doubt. I would expect him to be a bit more ambitious.
Anyway, feel free to check:
It gives you the names of the organizations, the manner in which the funding was funneled, links to material on the authors, etc. However, I didn't want to bring this up in my first comment (although I hinted at this issue in the title) because one really should address the facts and the science first -- before getting into issues of possibly systematic dishonesty and questions of motive.
Before climate change, my personal obsession was with evolutionary biology and the attempt by creationists to achieve a more "balanced treatment" of the subject in the schools, that is, use the school systems to indoctrinate students - and get children to chalk up modern science to some sort of ideological conspiracy. However, I suspect there may be a bit more riding on the issue of climate change at this point, so I switched.
In all honesty I prefer studying the role of viruses and various retroelements in evolution over climatology. But we must all do our part, I suppose.
Please don't rely on the BBC as an authority on any politically sensitive topic, look at other sources too, like:
It seems quite obvious to myself and other parties that the BBC has a heavy bias towards left wing, trendy, politically correct views, so are not as impartial as they make out they are, unfortunately this means that they are heavily invested in the reduce CO2 lobby. If we eventually get a decent (non-PC) government, hopefully they will do something to rebalance the BBC to a neutral political stance.
Other conventional media also tend to have tunnel vision and biases, so can also provide distorted news stories.
Channel 4 seems to be one of the few TV broadcasters willing to also show non-PC material for a variety of areas, including serious topics like climate research.
"Nice ad hominem. (dot dot dot) Every one of the authors is closely associated with at least one organization that is receiving funding from Exxon. (etc)"
Apart from being an ad hominem attack in itself, that's an extraordinarily vague accusation. Are there any employed people in the first world who are not "closely associated with at least one organisation that is receiving funding from Exxon"? That would include people who drive cars, people who own anything that is made out of plastic, and people who wear clothes.
There's something annoying about all the climate problematic, from a stupidly basic fact... Where's the sun's changes influences taken in account ?
If all these models and studies about atmosphere's changes related to climate changes are trivially based on the sole asumption or postulate that change in atmosphere has to imply change in climate, scientifics may have simplify a bit too much to try to find possible models.
After all, changes have happened both in atmosphere and climate way before human started to mess with them, and the sun's activity does not seem to be a flat constant. If the lack of any data about the sun's activity variations is a reason to forget about it in the models, I think we may have a scientific consensus about the existence of God before these models approach any truth.
What I find most annoying is the political obsession with greenhouse effects which seem just a bit too convenient to hide a couple of problems where human's activity can't be denied : water pollution and soil depletion for example.
Malthus wasn't wrong. He didn't know we could artificially improve culture's returns with oil based chemicals. We bought a delay on the deadline, but think about it again taking in account it seems in average the USA are wasting 10 cal of oil to produce 1 cal of food, and check why the grains prices are going high in the markets ?
Ashley Pomeroy quoted me,
"'Nice ad hominem. (dot dot dot) Every one of the authors is closely associated with at least one organization that is receiving funding from Exxon. (etc)'"
... then responded,
"Apart from being an ad hominem attack in itself, ..."
As I said, "However, I didn't want to bring this up in my first comment (although I hinted at this issue in the title) because one really should address the facts and the science first -- before getting into issues of possibly systematic dishonesty and questions of motive."
You deal with the facts and the arguments first, then you turn to questions of honesty and motive. If this weren't valid, any time you questioned someone's honesty or examined the possibility that they might be engaged in a form of deception you would be guilty of engaging in a logical fallacy. But obviously there are times when it is appropriate to consider issues of honesty. I examined the science and the arguments -- although not in the depth that I would prefer. However, you can look up more at www.realclimate.org -- if you wish. They have a search box.
Ashley Pomeroy continues,"... that's an extraordinarily vague accusation. Are there any employed people in the first world who are not 'closely associated with at least one organisation that is receiving funding from Exxon'? That would include people who drive cars, people who own anything that is made out of plastic, and people who wear clothes."
I am not speaking of anyone who has bought gasoline within the past 50 years. I said "closely associated."
Let's consider Fred Singer for a moment:
1. President, The Science & Environmental Policy Project. Documented funding from Exxon since 1998: $20,000.
2. Editorial Advisory Board Member, Cato Institute. Documented funding from Exxon since 1998: $110,000.
3. Advisory Board Member, American Council on Science and Health. Documented funding from Exxon since 1998: $125,000.
4. Adjunct Scholar, National Center for Policy Analysis. Documented funding from Exxon since 1998: $465,900.
5. Research Fellow, Independent Institute. Documented funding from Exxon since 1998: $70,900.
6. Former Fellow, Hoover Institution. Documented funding from Exxon since 1998: $295,900.
7. Former Fellow, Heritage Foundation. Documented funding from Exxon since 1998: $585,000.
8. Former Fellow, The Advancement of Sound Science Coalition. Documented funding from Exxon since 1998: $30,000.
9. Adjunct Fellow, Frontiers of Freedom. Documented funding from Exxon since 1998: $1,037,000.
10. Speaker, Centre for the New Europe. Documented funding from Exxon since 1998: $170,000.
11. Expert, Heartland Institute. Documented funding from Exxon since 1998: $791,500.
12. Contributing Writer, Weidenbaum Center. Documented funding from Exxon since 1998: $120,000.
13. Contributing Writer, Federalist Center. Documented funding from Exxon since 1998: $90,000.
Grand total documented funding of organizations that Singer is associated with by Exxon since 1998:
Incidentally, I got some of this information from:
... but most of it is from the link I provided earlier:
Singer has quite a history -- as his entry in Source Watch attests to. So does Christy:
The other authors don't have a writeup on SourceWatch as of yet, though. But Douglass has coauthored other equally flawed pieces with Singer and Patrick J. Michaels (another Exxon superstar) on a number of occasions.
The scientific case for our understanding of anthropogenic global warming is quite strong. If you haven't the time to learn about all of the science yourself, you may want to examine the statements by scientific bodies in this matter.
Every major scientific organisation which has issued a statement in this matter has come down on the side of climatology. In large part it really is just a matter of physics -- despite the complexity of the climate system.
However, I would recommend learning as much you can -- if it at all interests you. From what I can see there is a fair amount at stake in the coming decades, particularly in terms of our coastal cities, agricultural production and water supplies. If we continue along our current trajectory, the loss of life and effects upon the world economy in the latter part of this century looks to be quite substantial.
The so called "scientists" can't predict weather for a month in advance, what makes abyone think they can, with ANY kind of accuracy, predict what the weather will be like in one, ten, or twenty years in the future.
No my friends, this is not science but pure politics, supported by third rate politicians (Al Gore, et al).
greg wrote, "There's something annoying about all the climate problematic, from a stupidly basic fact... Where's the sun's changes influences taken in account ?"
I strongly suspect that the sun hasn't entirely escaped the attention of the entire climatological profession for the past century.
Actually, according to a variety of studies the sun has been essentially flat since about 1950, and best estimates given by the Nasa GISS, it would appear that forcing due to well-mixed greenhouse gases has been greater than any positive 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
… as well as the data at:
Global Mean Effective Forcing (W/m2)
Incidentally, the data for the levels of various gases, aerosols and the like are obtained independently of models -- and the same models with the same physical equations and code get applied to understanding paleoclimates, e.tc.. You can't really just tinker with them to make them fit as an exercise in curve-fitting -- as a tightening of the fit in one area would result in a loosening of the fit in a dozen others. However, when the fit is bad in a particular area, you can look to see what physics is missing, incorporate it, and chances are the fit in that area and several others will become considerably tighter. They are a work in progress -- but they have already progressed quite a bit.
They seem to be doing a rather good job of making predictions. Not simply in terms of the trends in global temperature, either. They predicted the cooling of the stratosphere, polar amplification where the Arctic latitudes would warm more rapidly than the lower latitudes, the fact that nights would warm more rapidly than days and winters more rapidly than summers. They predicted the expansion of the Hadley cells which govern the extent of the tropics.
They predicted the super greenhouse effect in the tropics where backradiation from the clear sky climbs more rapidly than thermal radiation from the surface as the surface warms above 30 C. They do quite well in describing ocean circulation - and have since 2000. They show, for example, changes in ocean circulation resulting from land warming more rapidly than ocean which result in growing deadzones off the US west coast. They predicted the expansion of the range of hurricanes and cyclones (e.g., Catarina, the first recorded South Atlantic tropical cyclone in 2004 and Gonu in the Arabian Sea in 2007).
They are tested using paleoclimate records and hindcasting. And Jim Hansen's Scenario B (one of three scenarios presented before the US Congress in 1988 made using single runs of a fairly primitive model by today's standards, the one scenario which he stated was most realistic at the time) was pretty much dead-on in terms of predicting the trend in global average temperature -- for the next twenty years.
It doesn't matter who they work for; the fact remains that consensus is not proof. realclimate.org folks have a vested interest in maintaining their position, as do many of the other bandwagon jumpers... You can wallow in the funding game, but that's a distraction and certainly doesn't buttress the scientific underpinnings of your argument.
Please go argue with these folks on a scientific basis, if you harp on their funding I'll know for a fact you don't know what you're talking about.
I disagree entirely with the notion of scientific consensus, it's crap honestly, it's sort of like agreeing with the Wall Street concensus that Enron was actually making money, even though there was plenty of legitimate suspicion that they were a fraud.
Koolaid drinking and group think afflict scientific and academic types, I'd say more so than in other endeavors, and what's a better way to get funding that predicting doom or the compromise of our precious bodily fluids by the fiendish florida^H^H^H^H "big oil"?
Also, if it's just a matter of physics, what kind of physics? Traditional Newtonian/Einstein or Quantum ? They don't necessarily agree...
Another question: Why did the AGW crowd decided to fly to Bali, mostly in private Aircraft? Seems that the biggest proponents of the theory don't actually *act* like this is a real issue, so why should anyone else?
Is this just another case of four legs good, two legs better but with spiffy lab coats?
"The so called "scientists" can't predict weather for a month in advance, what makes abyone think they can, with ANY kind of accuracy, predict what the weather will be like in one, ten, or twenty years in the future."
I'd have to remind you that, in complexity science, it is usually the case that the big picture is easier to see and accurately predict than the fine details (that may not be the case with climate science yet, I'm not sure, but that is the general point). But since you are so advanced you can tell the guys are "so called scientists", just like that, then I believe I won't need to explain any further, right?
The sun has not been 'essentially flat'. It never is; the sun is a variable star. I gathered a few links:
Solar activity: http://www.space.com/scienceastronomy/sun_output_030320.html
..not a flat line in sight.
In fact, Mars shows signs of 'global' warming as well, most probably because of solar activity:
in 2001: http://www.space.com/scienceastronomy/solarsystem/mars_snow_011206-1.html
..and in 2007:
We may be entering a new phase of solar inactivity, however:
btw, solar cycle 24 looked like it was about to start a few weeks ago:
The interesting question has come up on a couple of blogs, and it is not really whether the models predict water vapor adequately.
The thing we need to know is what, if it happened or was observed, would decisively disprove the CO2/warming hypothesis. Now, given that CO2 warming in itself is small, and anyway that two thirds of what we would expect from its doubling to about 600ppm has already happened, such events will have to be found, if they exist, in the hypothesized feedback loops which allegedly amplify the small amount of warming which is directly due to CO2 rises.
Either these loops are real or they are not. What a number of studies are trying to do is find out. Whenever they are published, we hear the usual cries of Exxon funding, bias, the laws of physics and so on. However, there are some real questions. Are water vapor levels behaving as they will have to, in order for the feedbacks to work? Is the surface station record reliable and robust, so is the hypothesized warming actually happening? Is the Ocean absorbing the hypothesized amount of heat? Are particulates involved in feedback loops of the right size?
Convinced AGW opinion is uniformly negative about any attempts to investigate these issues, and generally hostile to any attempts to establish what would falsify the CO2 hypothesis. This does not disprove it. But it does lead one to sense a strong smell of fish in the area.
Reaction to this study is no exception. If its wrong, fine. Lets go make some other predictions about feedback loops, agree in advance what they will mean, and then look to see if they're happening. Heaping personal abuse on critical scientists is not advancing science one bit. Nor is it making any converts to AGW.
As a weather-forecasting friend of mine explained to me recently:
"Climate is what we expect, weather is what we get"
Don't confuse the ability to predict when it is going to rain a few days hence (weather forecasting) with the discipline of climate change research. Although some of the techniques used are similar, they are quite distinct fields.
RealClimate.org was created by the PR company EMS.
In turn EMS, or "Environmental Media Services" was created by Arlie Schardt. Schardt was a journalist who became Al Gore's PR guy. He's a former sports writer who became a professional scaremonger:
>> As press secretary for Al Gore’s disastrous first presidential campaign in 1988, he warned then-Senator Gore: “Your main pitfall is exaggeration.” <<
Therefore, I put no more credence to an opinion from RealClimate poster than I would one from a Creationist, or a Flat Earther.
and that MUPPET called Gore removes significant data from his graphs because it spoilt his argument about the causes etc. . . . so next he gets a Nobel prize?
jeez, next thing is good ol'Bob Mugabe being awarded the Peace Prize in 2008
but what SHOULD still concern us the most is that this indoctrination is being forced down our children's throats without any counter balance argument
PLEASE don't tell me the teachers are going to provide that . . . . we know better than that <sigh>
"Climate is what we expect, weather is what we get"
"Although some of the techniques used are similar, they are quite distinct fields."
yup, you got it . . . both HOPELESSLY inaccurate . . . and IMHO about as scientific as astrology
If I believed all I was told in the 1980s, we would have no oil and no ice. Hmm we still have shed loads of both.
And as for 'Global Warming' my father was telling me how in the 70's we were experiencing 'Global Cooling'. Go figure
As a non scientist I read what you all write and have spend time reading books and doing research on this 'Climate Issue'. To be fair I read up on both arguments. What did I find out:
That you appear (remember not scientist) to simply make the facts fit the crime.
Now IMHO from my research:
We are in a warming period: Our eliptical orbit has taken us closer to the sun. Graphs created by sceintists show that the temperature is not as high as the highest ever.
Ice is melting: See last point.
Less rain: Recent higher solar activity blowing causing solar winds which in turn blow ions from the atmosphere (required to hold water)
CO2 levels high: Caused partially by us, however forest fires and Volcanic eruptions odvisouly have nothing to do with that. Of course knocking down miles of rainforest has nothing to do with that either. However CO2 levels have been a lot higher and hmmm Earth is still habitable.
CO2 ocean sinks not working as well: Underwater volcanos, releasing shed loads of CO2 straight into the sink. Need I go on.....
I am not going to go on, as no doubt there will be plenty of people who will disprove what I say. But I am not paid by the governments of this world to 'manufacturer' a reason to tax the f*ck out of me.
REMEMBER I am a IT bod NOT a scientist.
Simply put: As long as Governments in the world can get as much money as possible, ANY theory no matter how far fetched can be proved/disproved.
Remember no matter what the human race can do, nature can do one hundred fold worse. One average Volcanic eruption will emit more crap than what we can do in our cars in at least 100 years. Imagaine, just Imagine if Yellowstone (as it has before) blows again. Man what we humans have done will be totally and utterlty irrelevant.
/Just get my coat
This is in response to Anonymous Coward.
"Solar activity: http://www.space.com/scienceastronomy/sun_output_030320.html
..not a flat line in sight."
I said "essentially flat." You take a look at sunspots (a proxy for solar activity, where more sunspots is fairly well correlated with greater solar intensity and you will see increasing activity towards 1950, but essentially just standard quasiperiodic behavior since -- which looks quite flat if you do a running ten-year average. That is, unless you look a little more closely -- as there is a slight drop from roughly 1980 forward -- just as the trend in temperature really took off. Much the same is true with a more direct measurement by means of solar irradiance. It falls off when the rise in temperature becomes strongest.
You wrote, "In fact, Mars shows signs of 'global' warming as well, most probably because of solar activity:"
Warming? Yes. Due to solar activity? Not according to the Space article you link to.
From the article at Space:
"In one case, patches of snow disappeared during autumn in the northern hemisphere -- a time when cooler temperatures should have generated accumulations. A huge dust storm that raged in recent months and for a time covered the entire planet may have been responsible, temporarily raising global temperatures."
From an article it links to:
"Dust particles tossed high above the surface are being warmed by the Sun. They in turn heat up Mars' thin and mostly carbon dioxide-laden atmosphere."
Actually there would be a lot of problems with trying to tie "global warming" on Mars to solar output. For one thing, the temperature on Mars was falling during the 1970s even as our global temperature began its steeper climb. For another, there is that pesky solar irradiance.
Global warming on Mars?
5 October 2005
Still, the contrarians look to Mars and even the more distant planets as a means of maintaining that the solar variability is responsible for the warming trend of the past thirty years.
See for example "Larry King: Bill Nye vs. Richard Lindzen," http://www.youtube.com/watch?v=McsZ1U20W0M
... however, all of these are quite explicable as well.
Please see: Hot times in the Solar System, http://illconsidered.blogspot.com/2007/04/hot-times-in-solar-system.html
Given how remote the distant planets are, with Pluto for example being roughly 30 times as distant from the sun as the earth and with solar irradiance being inversely proportional to the square of the distance, to explain a rise in temperature of a couple of degrees out there by means of an increase in solar output would require levels that would render our planet virtually uninhabitable.
There are numerous threads to your post, enough so that they are something of a tangle. So I hope you won't mind if I pick just a few.
When you state that we already have two thirds of the warming from a doubling of CO2, this assumes that the warming is instantaneous, but that assumption is incorrect. The problem with greenhouse gases is that they create an imbalance between the amount of thermal radiation which is entering the system (when sunlight is absorbed) and the amount of thermal radiation leaves the system (given the fact that greenhouse gases are opaque to thermal radiation but transparent to visible light). As long as this imbalance exists, the climate system must warm up until it reaches a temperature which is sufficient for it to emit as much thermal radiation through the ir-opaque atmosphere as which is entering the system. And this takes time, primarily because of the ocean's thermal inertia. (It takes a while for the ocean to warm up and in effect "do its part" in emitting sufficient thermal radiation.)
You speaks of feedbacks and question whether or not they exist, stating specifically at one point, "Either these loops are real or they are not." But there isn't any question as to whether they are real. What open questions still exist are essentially a matter of the relative strengths of various feedbacks, some of which are positive, others negative, and thus what the overall climate sensitivity to a doubling of carbon dioxide will be.
If you raise the level of carbon dioxide, you increase the opacity of the atmosphere to thermal radiation, where the spectral properties of CO2 are quite measurable under laboratory conditions. This will result in higher temperatures resulting in evaporation -- where water vapor is itself a greenhouse gas. This results in a positive feedback.
However, more water vapor will likely mean more clouds, and more clouds generally mean an increased albedo with a reduction in the amount of sunlight which gets transformed into thermal radiation. This is a negative feedback.
But clouds also have a greenhouse effect, and the greenhouse and albedo of clouds roughly cancel one-another out, so that depending upon the altitude and thickness of the clouds, the net effect will be negative or positive. So how much feedback can we expect from the climate system for a doubling of carbon dioxide?
By itself, without the effects of water vapor or clouds, but simply given the spectral properties of carbon dioxide and its distribution in the atmospheric column, we would expect a warming of roughly 1.2 C. However, with the various feedbacks which exist within the climate system, a doubling of carbon dioxide is likely to result in something more like 2.8-2.9 C.
How do we know this? Extensive studies, some dealing with recent climate change, the reaction of the climate system to volcanic eruptions (or rather, to the reflective stratospheric aerosols they emit), etc., others involving the paleoclimate records of the past 420,000 years, etc..
I would recommend the following two papers
Annan, J. D., and J. C. Hargreaves (2006), Using multiple observationally-based constraints to estimate climate sensitivity, Geophys. Res. Lett., 33, L06704, doi:10.1029/2005GL025259.
Royer DL, Berner RA, Park J. (2007), Climate sensitivity constrained by CO2 concentrations over the past 420 million years. Nature, 446: 530-532.
The latter of these two is bringing together results from over 47 different studies.
Both still have a range on them. Annan might go as low as 2.6 C. However, given the uncertainties involved, significantly higher sensitivities are more likely than significantly lower sensitivities.
You ask, "Is the surface station record reliable and robust, so is the hypothesized warming actually happening?"
1. We have atmospheric measurements in the lower troposphere, the upper troposphere and the stratosphere.
2. These are measurements being taken by planes and satellites. The troposphere is warming - just as we would expect.
3. The stratosphere is cooling - just as is predicted by the anthropogenic global warming theory.
4. We are taking measurements of temperatures in the oceans both at the surface and at various depths. These are showing warming as far down as 1500 meters.
5. We are performing measurements of sea level - which has been rising as the result of thermal expansion.
6. We are performing gravitometric measurements of Greenland and Antarctica which are showing net ice loss in both cases.
7. We can witness sea-ice loss in the Arctic which is dramatically accelerating, with a historic sea ice area minima of a little over 4,000,000 km set in 2005, but less than 3,000,000 in 2007.
8. We are seeing the acceleration of glaciers in both Greenland and Antarctica, particularly within the last few years.
9. We are witnessing the rise of the troposphere.
10. We are witnessing the poleward migration of species.
11. We are witnessing the increased intensity of hurricanes due to the rise in sea temperatures.
12. We are witnessing the accelerating decline of glaciers throughout the world except in a few rare cases.
14. We are measuring the rise in temperatures at greater depths in the permafrost.
15. We are seeing the rapid expansion in the last few years of thermokarst lakes.
16. We are witnessing changes in ocean circulation.
17 We are seeing the disintegration of permafrost coastlines in the arctic.
18. We have seen the number of ice quakes in Greenland triple and the melt flow double within a decade.
19. We are getting temperature measurements from countries throughout the world which show the same trends.
20. When we perform measurements using only rural stations, we see almost identical trends.
21. We are witnessing changes in wind circulation patterns around Antarctica.
Yes, I believe the "hypothesized warming" is happening.
I did not mean to discount the work of true scientists, I meant to disparage the work of scientists who produce results to match the wishes of their "masters".
Unfortunately too many scientists supress the truth in ordere to gain favor from the "benefactors". That is worse than a corrupt scientists forging data...or is just more of the same.....
*yawns* this comment board reads like a bad wikipedia article.
Global Warming. The big bug bear of current modern man. Now there are two options
1) regress and slow progress (we all know what happens when Human states stop going forward, they collapse re: Roman Empire, Egyptian Empire, British Empire, Greece, Babylon, etc the same is also true of business and families when prospects dry up then infighting, division and death are inevitable without some kind of divine intervention) a conversion to inefficient renewable energy sources and costly nuclear fission. Sure the globe may become healthier - but what's the point if we have no tangible way forward stuck in a pre-atomic age rut.
2) Go forward, continue with our unsustainable energy use whilst looking for new means of generating energy, people like to point fingers at the petrochem industry but the truth is that those guys do the most research into renewable because they know that fossil fuels wont last forever. If we keep going forward we will produce large scale renewable power facilities using geothermal and other methods, and phase out old style reactors. At the end of the day energy is needed to create new larger energy sources.
Do we waste money on energy efficent light bulbs scrapping production lines and retooling factories at large energy cost or do we invest more time into making solar, wind and hydro more efficient?
Do we waste money building nuclear power stations and disposal facilities or build more oil and coal fired stations with scrubbers whilst beginning work on geothermals and new research ?
Do we spend money on an advertising campaign to turn off your TV or invest the money in sports so people aren't in their houses watching TV as much.
It doesn't really matter if Global Warming is real or not, what is important is that we move forward. Everyone can agree that they would like cleaner, long lasting, cost effective energy. You don't need to transport the Earths core, or the Sun or the Wind, but at the moment we can't effectively use it, throwing money into modern day renewable power is like flushing money down a low flush toilet, and slowing production and technological progress is cultural suicide.
My take is that:
1. This is becoming a fanatical religion to some. Nutters are nutters, regardless.
2. The entire closure of any discussion that refutes the claims is greeted with the old "La-la-la" whilst covering the ears.
3. Many of the proponents of AGW can't put a point across without absolutely drowning the reader with torrents of words and citations. Oh, yes, and telling us that a couple of the doubters are funded by conservative think-tanks, whilst conveniently discounting the fact that many of their fellow-travelers are from the socialist, "Let's redistribute the world's wealth" types whose agendas are furthered by this scaremongering.
4. However, when given references that refute the claims, they begin to assert that AGW causes EVERYTHING. How is this different from saying that it's witchcraft that's causing it?
After hearing the discussion, I am of the belief that there is a lot more POLITICS than science going on here. Scaremongering sells books, papers, and airtime. It also stampedes the sheeple into doing things that they wouldn't ordinarily do if thinking rationally. Although we are not doing the world a great favour in breeding as much as we do, we are being awfully conceited in thinking that we can create such changes in the overall climate.
BTW, what ARE Al Gore's credentials, anyway?
Real Climate - You guys are a bunch of mentally incompetent religious zealots.
You worship at the altar of Chicken Little....
Meanwhile, back in the real world...
Any one who paid attention in fifth grade science class knows that in fact:
The planet is cooling while the atmosphere and oceans are warming.
Here is a refresher in simple geophysics.
The earth formed with a MOLTEN core. Over time (A LOT of time) that molten rock has cooled via releasing MAGMA through breaches in the earths crust (i.e. The Ring of Fire).
While some of this activity happens on dry lad ( Volcanoes ), most happens in the oceans where this activity directly releases heat from the molten core in to the oceans.
Are you smarter than a fifth grader?
In response to Tim Chase, Ashley Pomeroy says "[saying] 'Every one of the authors is closely associated with at least one organization that is receiving funding from Exxon' is an extraordinarily vague accusation." Fair enough. Here's a detailed account of who paid whom to say what:
"Many of the proponents of AGW can't put a point across without absolutely drowning the reader with torrents of words and citations"
Or insinuating that everyone who disagrees is corrupt, as you say. These are the tactics of Senator McCarthy.
(Or Salem, Mass. The USA seems to be historically susceptible to fits of Puritanical finger-pointing).
Timothy Case has written several thousand words here, yet he has failed to address the two points raised by the article.
Firstly, the Douglass survey looks at the data output of the climate models themselves. This is welcome, and the kind of auditing one would expect climate modelers to perform on their own work regularly. The study finds that the models are contradicted by empirical evidence ... tropospheric models only work at sea level.
Case ignores this.
Secondly, the IPCC says it has only a "LOW" understanding of the role of particulate matter (ie, aerosols). This is very important, because particulate matter has a "negative" forcing effect: cooling the earth. In the second illustration (I wish it was larger) we can see that the IPCC admits that the cooling effect of particulate matter is as large as the heating effect of greenhouse gas.
Case ignores this, too.
What are the chances Sen.Timothy McCarthy can respond rationally in 200 words or fewer? I wouldn't like to take bets on this...
First: Blogs, "scientific" or not, are like a--holes, everybody has one, and they invariably stink.
Anyone quoting a blog as evidence of proof is an idiot.
We have been studying weather/climate for less than a hundred years. We have not learned enough to understand how Earths climate really works. We do not understand why we have periods of warming and cooling. Scientists have not been able to explain why we had ice ages after warm periods.
I will not discount true scientific proof, but as it stands current climate studies and models have been tainted by politics. This is no longer a scientific debate, but a political one. Politicians want more control over us, and this is just another platform for them to achieve that control.
Shame on the US (where I live) that we continue to build coal power plants, but have not built a nuclear plant in over twenty years. So before the politicos put the screws on us, ask them "Why?".
The old adage "Figures lie, and liars figure." aplies very well to the "global warming" debate.
Max states, "It doesn't matter who they work for; the fact remains that consensus is not proof."
Empirical science doesn't deal in proof. Proof belongs to Euclidean geometry and other mathematical constructs, but because they are capable of proof, we do not know whether or in what way they correspond to empirical reality. The currency in empirical science is testability and the cummulative weight of the evidence. In freshman philosophy one learns that in principle at least it is possible to coherently argue that the world came into existence only five seconds ago without actually contradicting any evidence. All one has to do is claim that whatever evidence of the world's apparent greater age, including one's memories, came into existence at the same time, perhaps as the result of an omniscient, omnipotent god or demon. But for that very reason science can't work that way.
It is always possible to cast doubt on any scientific proposition -- however unreasonable or unjustified such doubt may in fact be. The cigarette industry, particularly Phillip Morris, has made great use of this in the past, arguing that we can't actually prove that there are any ill effects associated with smoking. But of course there were and are. I submit that something similar has occured in the case of the fossil fuel industry. In fact I have pointed to a fair amount of evidence to this effect and resources where you can get more information if need be.
Of course there is also the argument that it will simply cost too much to deal with climate change -- and I believe this is part of the reason why the arguments from the fossil fuel industry get so much play. However, it is worth bearing in mind the fact that the same claim was made with respect to dealing with the problem of CFCs and the destruction of the ozone layer. Industries which manufactured CFCs found dealing with the issue inconvenient and portrayed action on this front as prohibitively costly. Now I have no doubt that the costs associated with dealing with climate change will be much more costly, but whatever the costs, it does not change the actual facts or consequences of climate change, and to deal with climate change we must first recognize it for what it is rather than attempting to deconstruct the evidence by means of extended exercise of cartesian doubt.
The longer we put off acknowledging the evidence for what it is, the more committed we will be to certain paths (such as the replacement of oil use with coal), the more costly it will be to switch to some other path, the less time we will have in which to act, and the more draconian (and perhaps futile) the measures that will in all likelihood be taken for dealing with a problem which for all intents and purposes we will simply no longer be able to ignore. Those who acknowledge climate change for what it is sooner rather than later will necessarily have a greater voice in determining how we respond to it -- as will we all.
Max writes, "realclimate.org folks have a vested interest in maintaining their position, as do many of the other bandwagon jumpers..."
No scientific discipline gets more research money by claiming that all the issues are settled. To the extent that climatologists make this claim, what they actually encourage is the shifting of investment from investigating climate change to the investigation of the means of dealing with climate change, such as alternate energy, bioengineering, or for that matter economics. (Incidentally, I myself am strongly pro- free market, but as identification precedes evaluation, science and the recognition of reality must precede politics and ideology. As a matter of principle, I have no choice in this matter.)
And RealClimate is well within the mainstream of climate science, like the IPCC. As I have noted, every major scientific organisation which has seen fit to take a position on anthropogenic global warming takes what is essentially a consensus view, namely that the evidence for it is overwhelming.
A rather extensive list of links to the statements by these scientific organisations may be found here:
I have argued before that the role of consensus (which is typically tacit rather than articulated -- as this is usually all that is required) in modern science is roughly on par to that of testability. In fact, testability largely rests upon tacit consensus. This is an outgrowth of an interdependence which exists between elements of our empirical knowledge, including scientific theories as well as the division of cognitive labor which necessarily exists in the modern scientific endeavor.
I won't go into either of these two issues in much depth here, but simply refer you to a couple of my extended comments elsewhere.
First, a critique of Karl Popper's Principle of Falsifiability which argues for the view that what science requires is testability rather than falsifiability as the result of an interdependence which exists between modern scientific theories (a slightly modified excerpt from a paper giving critical history of early twentieth century empiricism I did over a decade ago):
Do Scientific Theories Ever Receive Justification? - A Critique of the Principle of Falsifiability
Second, an analysis of the nature and role of consensus in science:
On “Scientific Consensus”
I don't expect you to really look at either of these, but I wish to make them available nevertheless.
Max states, "Please go argue with these folks on a scientific basis, if you harp on their funding I'll know for a fact you don't know what you're talking about."
Already deal with the science.
My first post, this thread's sixth. But after so many flawed papers being put out pretty much by the same list of people time and time again, we need to understand why they continue to be floated, spamming the newspapers with outlandish claims which have no actual scientific basis. People need to be aware of what is going on, particularly since they will often lack the time and expertise to examine each and every "technical" paper put out by the denial industry.
Max, you gave a link to the Inhofe 400 -- a list of "scientists" who presumably dispute anthropogenic global warming. However, the list is composed of numerous scientists who do not actually the basics but who may disagree about one or another detail -- yet had their names added without their consent, scientists who belong to disciplines largely unrelated to climatology (e.g., astrophysics, string theory), and people who aren't actually scientists at all -- including a television-gardener. It is being slowly analysed at rabett.blogspot.com, www.desmogblog.com, scienceblogs.com/stoat and a number of other blogs. No need to go into it in much detail, except to say that it is a good demonstration of how desperate the denial industry is at this point.
As I have indicated, the basis for anthropogenic climate change is quite strong -- every major scientific organisation that has seen fit to take a position on the issue has come down squarely on the side of climatology, and the list of organisations which have done so is quite long.
Dr Stephen Jones writes, "Timothy Chase has written several thousand words here, yet he has failed to address the two points raised by the article."
Middle initial of E? Just curious -- I might be familiar with your work, in which case I believe our understanding of the book Genesis will be quite different -- despite our both finding much value in it.
I will try to keep my response to you short since you seem to value brevity though I am afraid I will exceed your limit.
Stephen writes, "Firstly, the Douglass survey looks at the data output of the climate models themselves. This is welcome, and the kind of auditing one would expect climate modelers to perform on their own work regularly."
And they do in a large number of areas. You can get some sense of this for example from the pdfs for the GCM - Model E in use by NASA GISS:
They point out the flaws, the areas where improvements still need to be made. In fact they are quite open about it.
Stephen writes, "The study finds that the models are contradicted by empirical evidence ... tropospheric models only work at sea level. Chase ignores this."
The paper itself focuses on the tropical troposphere, and actually I dealt with that paper at some length in my first post in this thread, sixth post from the top. Additionally, the models are now extending beyond the stratosphere.
Stephen writes, "Secondly, the IPCC says it has only a "LOW" understanding of the role of particulate matter (ie, aerosols). This is very important, because particulate matter has a "negative" forcing effect: cooling the earth. In the second illustration (I wish it was larger) we can see that the IPCC admits that the cooling effect of particulate matter is as large as the heating effect of greenhouse gas. Chase ignores this, too."
I mentioned as much in my first comment (towards the end) and elsewhere in this thread. However, the uncertainties regarding aerosols have narrowed in the past couple of years. But if for some reason they were stronger than we think, this would imply that they are masking the effects of other more positive forcings, e.g., greenhouse gases, and given the largely exponential growth of the latter, things might be more serious than they already appear. But as I have indicated, I wouldn't worry about that.
Either way, one wouldn't want to use aerosols all that much to deliberately mask the effects of greenhouse gases -- as the reduction in sunlight would result in decreased agricultural production as it became necessarily to increase the levels of aerosols in order to keep up with greenhouse gases. Additionally, due to their acting as nuclei for smaller water droplets, they tend to decrease precipitation and thereby make drought more likely -- which will also tend to decrease agricultural production.
You had stated, "In the second illustration (I wish it was larger) we can see that the IPCC admits that the cooling effect of particulate matter is as large as the heating effect of greenhouse gas."
I failed to address that claim. Too focused on aerosols and the length of my post, I suppose.
However, I believe the chart you are thinking of is this:
... which they got from IPCC 2007 WG1 AR4, chapter two.
The forcings for anthropogenic greenhouse gases expressed in Watts per square metre are:
CO2 1.66, CH4 0.48, N2O 0.16, halocarbons 0.34, stratospheric ozone -0.05, tropospheric ozone 0.35, Total 2.94
direct effect -0.5, cloud albedo effect -0.7, total -1.2
... where the total aerosol effect faily to cancel so much as half the greenhouse effect of the greenhouse gases and would fail to cancel the forcing due to CO2.
Now of course, there are the ranges of uncertainty, such that it might be possible that one might not regard the residual of total aerosol forcing and CO2 forcing as statistically significant, but this would still leave the other greenhouse gases. Additionally, the uncertainties won't be additive, assuming one applies Bayesian logic.
Then one must also keep in mind the fact that there are other means of knowing the residual, combined effect independently of our knowledge of the individual effects. For an analogy, this would be much like how one may not know the rate at which water is entering a tub through an inlet or leaving it through an outlet, but can nevertheless know quite well what the rate at which water is accumulating in the tub by the rate at which the water level rises.
Finally, of course the essay for this thread deals with the possibility that we have been underestimating the indrect effect of aerosols. However, that isn't the IPCC - and if one considers the indirect effect of aerosols through their promotion of cloud formation and albedo, it would probably be wise to include their contribution to the cloud greenhouse effect as well as the greenhouse effect due to aerosols themselves. In the latter case, I am thinking of the Asian Brown Cloud that is amplifying global warming in Asia -- roughly by a factor of two.
Hope this helps...
I endorse the criticism that those who indulge in personal attacks rather than focusing on the science simply weaken respect for themselves.
I have a simple question which I haven't seen answered anywhere - which doesn't mean the answer isn't obvious. However:
Water vapour is supposed to be the magnifying factor for CO2 with the argument that more CO2 creates warming that increases atmospheric water content thereby further increasing warming. But this is a feedback loop that doesn't seem to require CO2 at all, since water vapour itself creates warming that increases atmospheric water content thereby further increasing warming ....
So presumably there are natural negative feedback processes that control this very major positive feedback process. How come these are not capable of controlling the much smaller CO2 contribution?
Alan, if I remember correctly, you have an interest in the paleorecord, so I will go into a little more detail in my response to you - using examples that may be of some interest.
Alan Wilkinson writes,
"Water vapour is supposed to be the magnifying factor for CO2 with the argument that more CO2 creates warming that increases atmospheric water content thereby further increasing warming. But this is a feedback loop that doesn't seem to require CO2 at all, since water vapour itself creates warming that increases atmospheric water content thereby further increasing warming ...."
Water vapour feedback does not require carbon dioxide. Remove the carbon dioxide, move the earth a little closer to the sun but give it the same orbital variations and tilt, and you would still have your glacials and interglacials -- although the cooling as you approach the glacials would probably be more rapid and the warming as you approach the interglacials would be slower. In other words, it amplifies the effects of solar incoming radiation (insolation) just as it amplifies the greenhouse effects of carbon dioxide.
Incidentally, carbon dioxide can and does act as a feedback as well, amplifying the effects of other forcings, but it is a "slow" feedback, like ice sheets. With carbon dioxide, the central issue is its residence time. If you inject a pulse of carbon dioxide into the atmosphere, a significant percentage of it will still be in the atmosphere thousands of years later.
So when the climate system is in equilibrium but then disturbed by greater solar insolation due to orbital variations (which are themselves parts the result of our orbit being disturbed by the gravitational fields of Jupiter and Saturn), this raises the temperature of the oceans, reducing their capacity to carry carbon dioxide (and oxygen, by the way), raising the level of carbon dioxide in the atmosphere. Then combined with water vapour, the higher concentrations of greenhouse gases amplify the effects of increased solar insolation.
If one looks at the paleoclimate record, it would appear that carbon dioxide typically acts as a feedback -- amplifying the effects of solar insolation. But there are points in the paleoclimate record where it is clear that what disturbs the climate system is an injection of either carbon dioxide or methane, the latter of which is a greenhouse gas 21 X stronger than carbon dioxide.
Four of the five major extinction events in the history of our planet appear to have begun that way. For example, the greatest extinction event, the Permian-Triassic, appears to have been the result of a carbon cycle forcing due to a Siberian supervolcano releasing large amounts of carbon dioxide into the atmosphere over a period on the order of a million years roughly 251 million years ago.
This would also have been amplified by carbon cycle feedback, including carbon dioxide being released from the oceans, methane being released from shallow water methane hydrates (with some forcing due to methane hydrates melted by the volcanic activity itself), marshes producing methane through organic decay, forest fires, and then a conversion of much of the biosphere into carbon dioxide simply as the result of the extinction event itself.
By the time it was all over, approximately ninety percent of all species living in the ocean had gone extinct and seventy percent of all species living on the land were gone as well -- with a ninety-nine percent mortality rate for the members of the surviving species. This point in the earth's history is sometimes refered to as "The Great Dying," and for a while it would appear that the dominant form of life was fungus. It took several million years for the biosphere to recover.
Regarding water vapour feedback, Alan writes, "So presumably there are natural negative feedback processes that control this very major positive feedback process. How come these are not capable of controlling the much smaller CO2 contribution?"
It is really is a question of residence time.
A fairly significant fraction of carbon dioxide will remain in the atmosphere for tens of thousands of years, but water vapour falls out of the atmosphere as precipitation. Starting with a climate system which is in quasi-equilibrium, an injection of water vapour into the atmosphere raises the humidity, but at the low temperature of the quasi-equilibrium, this simply means higher humidity, increased cloud formation, then additional rain or snow so that the water vapour settles back down to its original level.
The additional moisture will remain in the atmosphere for only a few weeks but for the temperature to rise signicantly as the result of the enhanced greenhouse effect would take decades. In contrast, with carbon dioxide remaining in the atmosphere for far greater periods of time, this limitation (with uptake by the carbon cycle due to plants, absorption by ocean and the much slower process of mineralisation) is far less important.
Incidentally, the greenhouse effect due to carbon dioxide isn't that much smaller than that of water vapour.
Once the peaks of the absorption in the absorption spectra are saturated, the absorption of radiation takes place principally in the wings, and as a result is to a first approximation roughly proportional to the logarithm of the concentration. Thus for the purpose of analysis of their effects upon temperature, it helps to think not in terms of the concentration of the greenhouse gases but in terms of their doublings.
And while those parts of the spectra where carbon dioxide would act in the lower troposphere are already saturated by water vapour, water vapour tends to be limited to the lower layers of the troposphere, and as such carbon dioxide is quite effective in the upper parts of the troposphere, stratosphere and above.
As such, while water vapour amplifies the effects of carbon dioxide, it is by no means proportional to their relative concentrations in the atmosphere. The enhanced greenhouse effect which would result from the direct effect of a forcing by a doubling of carbon dioxide in the atmosphere would be roughly 1.1 C. With all the feedbacks, we estimate it would be closer to 2.8-2.9 C, best estimate.