New peer-reviewed study suggests IPCC models overestimated warming feedback from CO2

Just as Chicken Little pontificates about the minutiae of a Monckton allegation about warming amplification being overstimated by six of seven times, along comes a new study in Nature that compared real data with the computer models and found CO2's feedback warming effect has been exaggerated in the models by five or six times.

Funny thing, serendipity.

A note for the pedants: the Monckton claim and the Nature paper are approaching a similar problem (magnitude of feedback warming) from slightly different directions (Monckton's comment relates to rise in temp caused by doubling of CO2, whilst the Nature paper examines the increase in CO2 caused by a rise in temperature), but the general thrust of the arguments is similar: extra carbon dioxide is not going to cause as much feedback as previously claimed.

UPDATE: Chicken Little's feathers are ruffled by my attempt to use non-technical language, so if you've just clicked through, here's how the Houston Chronicle reports it:

By ERIC BERGER
HOUSTON CHRONICLE

Jan. 28, 2010, 10:41PM

A pair of climate papers published this week in the world's top science journals may offer some hope that rising levels of carbon dioxide won't imminently bring the planet to boil.

One paper concerns the effect of a warming climate on oceans and other sources of carbon dioxide on Earth, and found they will be slower to release more CO2, and thus do less to amplify warming than previously expected.

The second study analyzed a decline in water vapor — a potent greenhouse gas — in the upper levels of the atmosphere and found that it may have contributed to a decade-long halt in the rise of global temperatures since 1998.

Both studies are a bit technical, but they are important because they get to the cutting edge of climate science.

Amid the over-reaching catastrophic claims of environmentalists on one side, and cries of global warming being a great hoax from the other, there is actually a good deal of common ground among scientists.

All agree concentrations of CO2 in the atmosphere are increasing, and there's a general agreement that a doubling of CO2 levels this century, by themselves, will produce an increase of 1.5 to 2 degrees Fahrenheit in global temperatures.

Positive feedback

By itself, this would not be catastrophic for the planet.

What scientists are actually interested in better understanding are so-called “feedback” loops from rising CO2 levels, which in turn could substantially amplify warming to catastrophic levels.

For example, as CO2 levels rise, and temperatures go up, the thinking is that the area of the planet covered by snow will decrease. Snow is very effective at reflecting heat back into space, so anything that replaces it will absorb more heat and further warm the planet.

This is a positive feedback. The question is: Will rising CO2 levels produce more positive or negative feedbacks?

For some scientists, including the skeptical Richard Lindzen of the Massachusetts Institute of Technology, the jury on feedbacks remains out.

“Climate science is a field that is not highly developed,” he said. “Really, it's still in its infancy.”

Other climate scientists would disagree, but as the two new papers this week show, researchers are still grappling to understand the balance of feedback loops.  (read the rest here)

Comments

[CM]

"Frank said it was hard to say how the new findings might have altered estimates in a report by the U.N.'s Intergovernmental Panel on Climate Change in 2007 that world temperatures could rise by between 1.1 and 6.4 Celsius by 2100.

"Of the models that did include the carbon cycle, our results suggests that those with slightly below average feedbacks might be more accurate," he said. "But we can't now say exactly what sort of temperature range that would imply.""

http://www.reuters.com/article/idUSTRE60Q51V20100127

Not quite the exaggeration that you are claiming Ian.....how come?

[CM]

"Australian expert Professor Andy Pitman of the UNSW Climate Change Research Centre in Sydney says the findings are both "good news and bad news".
It is good news because it suggests amplification is at the lower end of previous estimates, says Pitman. But bad news because it confirms there is an amplification.
He says the findings will help climate scientists to pin down the contribution of amplification, which has not been previously included in IPCC scenarios of due to the surrounding uncertainties.
But Pitman says he doesn't think that degree of amplification will be enough to substantially change IPCC climate change scenarios."

"Dr Mike Raupach from CSIRO Marine & Atmospheric Research in Canberra welcomes the study.
"It's a great analysis," says Raupach, but the findings will be of "limited help" in fine-tuning IPCC scenarios.
He says Frank and colleagues studied a period of relatively stable climate, when temperatures varied by only about 0.3°C.
Raupach says the amplification processes that are likely to occur over the next 100 years, if humans continue to emit high levels of CO2, may be quite different.
"We are taking the coupled carbon climate system well outside the range that has been experienced over the last 1000 years," he says.
Raupach says earlier interglacial periods, excluded from their study, saw much greater variability -100 ppm of CO2 and 5°C - and a much higher rate of amplification.
Raupach says an interesting by-product of the study is that it shows that the much-discussed Medieval Warm Period was not as warm as the current period."

http://www.abc.net.au/science/articles/2010/01/28/2802646.htm

[Ian Wishart]

I was quoting ScienceDaily rather than Reuters. The SD report shows how recent estimates have concentrated on the 40 ppmv level, whereas the empirical tests (real world data) showed a range between 1.7 (more than 20 times lower) and 21 ppmv, with a median of 7.7 - nowhere near the 40.

It's not saying there's no feedback, it's saying the feedback is well below the extreme levels pitched by Chicken Little and co.

[CM]

I hope they are right. But there is plenty in what I have quoted to mean this isn't necessarily good news. For a start, they studied a period of relatively stable climate, when temperatures varied by only about 0.3°C.

So that's the end of deniers claiming no amplification?

[Louie D]

No way CM just the end of "evil deniers" having to claim over amplification.
The more this whole issue is looked at the more holes that keep turning up.
soon the world will reach a point where corbon no longer forces warming ,and temps might still rise.
what then?.

[Andrew W]

Just another example of Deniers leaping on a study they don't themselves study in the expectation that finally there's proof that all those IPCC scientists are wrong.

Denialism, not scepticism.

[Truthseeker]

It's funny how people are so quick to judge "deniers". Skeptics would be a better word. Besides who just believes something blindly that Al Gore or the TV told them. I feel sorry for you for not scrutinizing the facts and deciding for yourself. Science needs to be checked and checked again and again to prove a theory. You can't just say "I proved it, the debate is over!" Get real and quit stumbling through life like a docile child.

[Truthseeker]

I forgot to mention, no one denies that the climate is changing. That's a natural cycle of the Earth. People are just questioning whether or not this change is caused by human activity. Because if you look at the big picture this global warming scare is just a ploy to get people to pay taxes for anything they do that requires energy. Al Gore wants to sell you carbon credits and become even richer off of you saps who will believe his carefully crafted lies. Need I remind you that Al Gore claimed to invent the internet in the past? How do we know that humans cause global warming? How do we know it isn't caused by solar activity, like solar flares? You know why they picked Carbon Dioxide (CO2) as the scary monster? Because it's part of the life cycle. Humans and animals breathe out CO2 and plants absorb CO2, basic chemistry/biology. This global warming scare is an attack on life. Come on people... Be people and not sheeple.

[CM]

>>>It's funny how people are so quick to judge "deniers". Skeptics would be a better word.<<<

People need to know what they're talking about AND demonstrate objectivity before they can earn tag of skeptic. Based on what I've seen on the internets I would guess there are 1000 deniers for every skeptic.

>>>Besides who just believes something blindly that Al Gore or the TV told them.<<<

Morons. How is that relevant?

>>>I feel sorry for you for not scrutinizing the facts and deciding for yourself.<<<

Ditto.

>>>Science needs to be checked and checked again and again to prove a theory.<<<

Indeed. Which is what has been happening. Science related to climate has been scrutinised and checked more than any other area of science that has ever existed. More detail and evidence is available to the public than in any other area of science ever.

>>>You can't just say "I proved it, the debate is over!" <<<

You should read all the clear uncertainties tagged in the IPCC reports. And all the published papers. Instead of just making stuff up.

>>>Get real and quit stumbling through life like a docile child.<<<

Quite.

[CM]

>>>I forgot to mention, no one denies that the climate is changing. That's a natural cycle of the Earth.<<<

You're actually Ian 'it's the height of rudeness!' Plimer aren't you?

>>>People are just questioning whether or not this change is caused by human activity. Because if you look at the big picture this global warming scare is just a ploy to get people to pay taxes for anything they do that requires energy. Al Gore wants to sell you carbon credits and become even richer off of you saps who will believe his carefully crafted lies. Need I remind you that Al Gore claimed to invent the internet in the past? How do we know that humans cause global warming? How do we know it isn't caused by solar activity, like solar flares? You know why they picked Carbon Dioxide (CO2) as the scary monster? Because it's part of the life cycle. Humans and animals breathe out CO2 and plants absorb CO2, basic chemistry/biology. This global warming scare is an attack on life. Come on people... Be people and not sheeple.<<<

You should write for The Onion. Or http://denialdepot.blogspot.com/
Maybe you already do?

"However what makes me deeply suspicious is the complete lack of correspondence with Al Gore in these released emails. Where are all the emails showing Al Gore's involvement? Even more bizarrely there is no plotting and planning on how to raise taxes. I don't see any mention of the socialist new world order that these scientists are trying to bring about. Not once do they talk about how to best achieve wealth redistribution or world government.

So I have to conclude this this email release is a big con. It has all the hallmarks of a deliberate leak to make these scientists look better and to try and silence skeptics who question their motives. If we are to believe the emails, the scientists don't actually think their work is in error! But we know they must realize it's all a big con, so how can these emails possibly be true?"

http://denialdepot.blogspot.com/2009/11/nasas-fakes-email-leak.html

Brilliant. One of yours?

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