New paper in Nature on CO2 amplification: "it's less than we thought"

Amplification of Global Warming by Carbon-Cycle Feedback Significantly Less Than Thought, Study Suggests

http://svs.gsfc.nasa.gov/vis/a000000/a003400/a003440/airsCO2_printres.0392_web.png

This image shows the global monthly average Carbon Dioxide in July 2003 as seen by Aqua/AIRS.

from ScienceDaily (Jan. 28, 2010) — A new estimate of the feedback between temperature and atmospheric carbon dioxide (CO2) concentration has been derived from a comprehensive comparison of temperature and CO2 records spanning the past millennium.

The result, which is based on more than 200,000 individual comparisons, implies that the amplification of current global warming by carbon-cycle feedback will be significantly less than recent work has suggested.

Climate warming causes many changes in the global carbon cycle, with the net effect generally considered to be an increase in atmospheric CO2 with increasing temperature — in other words, a positive feedback between temperature and CO2. Uncertainty in the magnitude of this feedback has led to a wide range in projections of current global warming: about 40% of the uncertainty in these projections comes from this source.

Recent attempts to quantify the feedback by examining the co-variation of pre-industrial climate and CO2 records yielded estimates of about 40 parts per million by volume (p.p.m.v.) CO2 per degree Celsius, which would imply significant amplification of current warming trends.

In this week’s Nature, David Frank and colleagues extend this empirical approach by comparing nine global-scale temperature reconstructions with CO2 data from three Antarctic ice cores over the period ad 1050-1800. The authors derive a likely range for the feedback strength of 1.7-21.4 p.p.m.v. CO2 per degree Celsius, with a median value of 7.7.

The researchers conclude that the recent estimates of 40 p.p.m.v. CO2 per degree Celsius can be excluded with 95% confidence, suggesting significantly less amplification of current warming.

Journal Reference:

  1. David C. Frank, Jan Esper, Christoph C. Raible, Ulf Büntgen, Valerie Trouet, Benjamin Stocker, & Fortunat Joos. Ensemble reconstruction constraints on the global carbon cycle sensitivity to climate. Nature, 2010; 463 (7280): 527 DOI: 10.1038/nature08769

Full story here at Science Daily

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Ray

Are they trying to hide the overestimated rise promoted by their climate models?
What about anthropogenic carbon dioxide has ZERO impact on climate?

Rut Ro!
Of course, this can simply be trashed like the Soon / Baliunas 2003 paper was. After all, it doesn’t agree with the reality of the world as expressed in the models.

Chad Woodburn

Maybe it is already clear to others, but how much of a reduction in the amplification does this indicate? Or to put it another way, based on this report, by what percentage have the IPCC-Gore-Hansen crowd been overstating the effect of warming due to CO2?

latitude

Well of course it is. The weather/climate is not cooperating and not agreeing with their models.
Just like Menne had to rush a paper out trying to disprove Watts/Pielke Sr, first, before Watts/Pielke Sr could get theirs out.
They are just CYA.
Now they can still say “see we were right”.

TerryBixler

Not quite an order of magnitude. Close as in horse shoes. This should have been in the state of the union message “crisis over we have solved the problem through bipartisan support and effort….” Shortly Mz Jackson will refund some of her EPA budget increase in sympathy with the job loss due to her threats oops findings.

Soller

@Ray (12:27:35)
The BBC article is more detailed: http://news.bbc.co.uk/2/hi/science/nature/8483722.stm
“for every degree Celsius of warming, natural ecosystems tend to release an extra 7.7 parts per million of CO2 to the atmosphere (the full range of their estimate was between 1.7 and 21.4 parts per million).
This stands in sharp contrast to the recent estimates of positive feedback models, which suggest a release of 40 parts per million per degree; the team say with 95% certainty that value is an overestimate.

Murray

So for o.8 degrees C warming in the last 100 years we would have about 6 ppm increase in CO2 using their mid range estimate. I did a crude stab at such an estimate using ice core data a couple of years ago and estimated <10 ppm of the increase we have seen was due to warming. Seems reasonable, and hardly a cause for concern.

Neo

The science is “settled” … like solids in a cesspool

RobJM

Henry’s law already describes the relationship between water temp and CO2 in the atmosphere. This is just a way to claim humans are responsible for the CO2 increase rather than the fact that 95% of the increase is due natural ocean warming. For every 50 molecules of CO2 we produce, only one will remain in the atmosphere at equilibrium, which takes about ten years based on CO2 ocean atmosphere exchange.

Tamara

Bah ha ha ha ha ha ha ha ha ha ha ha ha ha. Oh…my sides! bah hah haha.

Since the response to CO2 is a log function it implies that the positive feedback effect will decline with increasing concentrations. And in any case it is a minor factor compared to water vapor.

Bernie

Lubos is discussing and clarifying the paper at his site:
http://motls.blogspot.com/2010/01/nature-carbon-cycle-feedback-is-80.html

John Finn

The authors derive a likely range for the feedback strength of 1.7-21.4 p.p.m.v. CO2 per degree Celsius, with a median value of 7.7.
Two points emerge from this:
Firstly, Hans Erren’s “quick and dirty” method using vostock ice core data produced an estimate ~10 ppm per deg C. Not bad for a 30 second calculation. See here:
http://members.multimania.nl/ErrenWijlens/co2/howmuch.htm
Secondly, this surely settles any debate about mankind’s involvement in the increase in 20th century CO2 concentrations. The CO2 increase cannot be due to higher temperatures.

This means overstated temp estimates of about a third, according to one skeptic physicist:
http://motls.blogspot.com/2010/01/nature-carbon-cycle-feedback-is-80.html

Bernie

One major issue that I see is that the researchers are using proxy records to do their estimations. Skeptics cannot have it both ways. Either the proxy records are problematic or they are not.
The only safe conclusion is that some people are way too certain about climate sensitivity.

Ben

According to IPCC figure 9.9, anthropogenic contribution to temperature rise is about 90% in the seconde half of the XXth century, with CO2 being the main forcing agent.
How would this paper change the anthropgenic/natural contribution to temperature rise ?
Thx

They have been overstating by between 89% and 235%.

KTWO

One is tempted to paraphrase:
The science was right before, the earlier numbers misbehaved. “Bad. bad, numbers. Depart from us. Hence forth we will use different numbers.”
More seriously. It sounds like careful work. I hope it holds up.

Steve Goddard

The geologic record shows no correlation between CO2 and temperature.
http://ff.org/centers/csspp/library/co2weekly/2005-08-18/dioxide_files/image002.gif
There was an ice age in the late Ordovician with CO2 levels 10X of current levels. Hansen et al are not interested in looking at geological timescales though, because it would nullify their raison d’etre.

Scott B

I have my doubts about this. Still haven’t had a chance to read through the whole paper, but the list of temperature reconstructions used should raise a few eyebrows:
Jones199831 (blue 3), Briffa200032 (blue 2), MannJones200333 (blue 1), Moberg200534 (light blue), DArrigo200635 (green), Hegerl200736 (yellow), Frank200737 (orange), Juckes200738 (red), Mann200839 (maroon)
There’s a fine collection of hockey sticks.

The German Der Spiegel had a story on this yesterday. They did admit, that the feedback effect would be smaller than previously thought, but:
There would be absolutely no reason to take back any previous warning, because:
-human CO2 emissions would rise rapidly, anyway
-the scientists could not simulate feedbacks which occur at larger temperature variations than we have seen the last 1000 years (e.g. because of the evil methane there could be unprevedented feedbacks)
Furthermore other researchs would suggest that climate change would have been underestimeted so far (sic!), e.g. 5 Million years ago it was warmer than today, with CO2levels only slightly higher.
The conclusion of the article was: Possibly an atmospheric CO2 concentration of 400-500 ppm is enough for a runaway warming…
So still, even if climate feedback is lesss than we feared, it is still worth than we thought. Yes, repeat no…

MikeEE

I’m a little confused about this AGW theory.
From what I think they’re tell us, regardless of amplification:
If the earth warms as a result of increased atmospheric CO2
that warming results in a warmer ocean
warmer oceans hold less CO2, thus expelling it to raise atmospheric CO2
hence CO2 and temperature go up forever.
According to the commonly discussed theory, why wouldn’t this continue to runaway?
MikeEE

Brent

At least they got the general flow right. If you increase temperature….. you increase as co2 as it comes out of solution from the ocean

“Secondly, this surely settles any debate about mankind’s involvement in the increase in 20th century CO2 concentrations. The CO2 increase cannot be due to higher temperatures.”
Probably so, but absent the warming fear we can strip CO2 of all of it’s undeserved bad press and accept it for it’s pro-botanical effects on the planet.

Bill DiPuccio

There is a more complete explanation of the article by the BBC:
http://news.bbc.co.uk/2/hi/science/nature/8483722.stm
“Some climate sceptics have argued that a warmer world will increase the land available for vegetation, which will in turn absorb CO2 and temper further warming. This is known as a negative feedback loop – the Earth acting to keep itself in balance.”
“But the Nature research concludes that any negative feedback will be swamped by positive feedback in which extra CO2 is released from the oceans and from already-forested areas.”
“…”It might lead to a downward mean revision of those (climate) models which already include the carbon cycle, but an upward revision in those which do not include the carbon cycle.
“That’ll probably even itself out to signify no real change in the temperature projections overall,” he said. “

Then there’s this insanity. The public just doesn’t ‘get’ it. Cold is warm. Up is down.
http://www.msnbc.msn.com/id/35118098/ns/us_news-washington_post/

Mark this one on the calendar! Instead of “worse than we thought,” as is usually the case, it says “less than we thought.” I’m going out now to see if there are any pigs flying around.

Neven

Excuse me if this is a dumb question, but what does this say about climate sensitivity to a doubling of CO2?
And does it have anything to do with carbon sinks (oceans, fauna) becoming saturated?
Am I right in I thinking that from a warmist point of view this is good news, meaning there is more time to transition to a sustainable society?

Jeff (from Colorado)

I am amazed at how in the picture the tropics (especially South America) absorb so much CO2 that they leave a visible trail of lower CO2. Does this mean that as the higher concentration in the northern hemisphere mixes and some travels to the southern hemisphere, that it all gets absorbed? Has this Amazon rate been studied?

Not Amused

And yet another peer-reviewed paper that debunks the alarmist tongue wagging that skeptics have no science to back their arguments.
The issue of feedbacks will make or break AGW.

Neven

The BBC article seems to answer most of my questions. I think that for the sake of objectivity and impartiality it might be a good thing to add these lines to this blog entry:
“The authors warn, though, that their research will not reduce projections of future temperature rises.
Further, they say their concern about man-made climate change remains high.
The research, from a team of scientists in Switzerland and Germany, attempts to settle one of the great debates in climate science about exactly how the Earth’s natural carbon cycle will exacerbate any man-made warming.
Positive, negative
Some climate sceptics have argued that a warmer world will increase the land available for vegetation, which will in turn absorb CO2 and temper further warming. This is known as a negative feedback loop – the Earth acting to keep itself in balance.
But the Nature research concludes that any negative feedback will be swamped by positive feedback in which extra CO2 is released from the oceans and from already-forested areas.
The oceans are the world’s great store of CO2, but the warmer they become, the less CO2 they can absorb. And forests dried out by increased temperatures tend to decay and release CO2 from their trees and soils. ”
Source: BBC

geo

I was starting to get excited, and then I saw “nine global-scale temperature reconstructions” and said to myself “uh oh”.
So. . .which nine GSTR did they use, and do any of them have the MWP at anything like a likely scale? And if they don’t, what happens to their results if a real MWP is included?
I also wasn’t real clear (I think not, but I’m not sure) if this was a different issue that they were looking at than the positive wator vapor feedback thing? Same issue or different one?

Crispin

It seems that 40 (modelled) divided by 7.7 (probable) = a 5.2 fold modelling claim beyond the empirical values.
Projecting 2.0 deg by 2100 / 5.2 = 0.4 which is close to a number of other opinions. The point about non-linear response above is noted. Perhaps 0.3 then, with a natural background variation of 3-4 (my opinion).
Regards

Nature supported the idea of positive feedback before they didn’t.

Dave Wendt

It’s nice that Nature is showing a willingness to publish some slightly contrarian info, but since the authors used Antarctic ice cores for CO2 which seem to be more than a bit problematic and compared them to paleoclimate reconstructions, which I’m unwilling to invest $32 to identify but in general I’ve never found to be confidence inspiring, I doubt I’ll be adding this to my reference file.

Ray

Soller (12:35:17) :
I was not talking about total CO2 but only ANTHROPOGENIC CO2… The anthropogenic part of the total CO2 is insignificant and will insignificantly contribute to any positive OR negative feedback. In other words: We have zero impact on global temperature change, 0. Of course, I am saying 0 with only 1 significant figure… I too have some uncertainly.

Dr A Burns

The authors claim that based on Antarctic ice cores, increasing temperatures release less CO2 than previously thought. In other words, increasing temperatures cause CO2 concentration increases, not the reverse. It seems rather twisted logic to claim feedbacks based on such data.

I can hear Gavin Schmidt cursing now. This is another paper where he will have to find some way to trash it on RealClimate.

James Sexton

I wondering how they’re going to spin that one. I’m sure they’ll think of something. OT, but Fox is running yet another story re: the IPCC’s incompetence. I think we finally got them monitoring this site. http://www.foxnews.com/scitech/2010/01/28/save-rainforest-climate-change-scandal-chopped-facts/

This paper adds further support to what the chemical engineers have known all along: CO2 can have no influence on average earth temperature due to process control fundamentals. I’ve placed this link here before, but this seems like a good time to post it again. Perhaps in a few more iterations and/or papers published, the scientists will agree with the engineers.
http://sowellslawblog.blogspot.com/2009/02/chemical-engineer-takes-on-global.html

Henry chance

“The authors derive a likely range for the feedback strength of 1.7-21.4 p.p.m.v. CO2 per degree Celsius, with a median value of 7.7”
Talk about impressive pinpoint accuracy.
Is that like forcasting warming to be represented by anomalies of the same magnitude?
With that wide fat range, they can’t be proven wrong.

Richard

Am I correct in assuming that “co-variation” is the same as amplification?
If that be correct then a co-variation of 7.7 is over 500% less than the co-variation of 40, which can be excluded with 95% confidence.
What about “co-variation” factors that lead to negative amplification / acceleration, such as those that come into play when temperatures are falling while CO2 is rising as during the start of an ice-age, or in the last decade?

TJA

Oh look, they got the stratosphere and water vapor wrong too…
http://www.nature.com/news/2010/100128/full/news.2010.42.html

TJA

Now the big boys are moving in doing the real science.

John Finn (12:43:31) :
Secondly, this surely settles any debate about mankind’s involvement in the increase in 20th century CO2 concentrations. The CO2 increase cannot be due to higher temperatures.

1) The temperature rise is a lot less than slated.
2)1940’s co2 levels were measured to be higher than 1975’s co2 levels.

Neven:
“The authors warn, though, that their research will not reduce projections of future temperature rises.”
Neven, these people have to appear to be agreeing with the AGW narrative even while they are disagreeing with it. In many cases their research grants depend on it. The important thing is that the climate sensitivity number keeps getting walked down, little by little.

Al Gore's Holy Hologram

There is no p.p.m.v. CO2 per C degrees of temperature. Nature doesn’t work in such a linear way. If you could make such linear predictions, or any predictions, about a chaotic non-linear system then we’d do the same with the stock market like so many charlatans try to convince people they can do.

Richard Heg

“Its less than we thought”
and accelerating?

Coals

Is this paper saying that since warming itself is not the cause of as much of the observed C02 buildup as previously thought then the measured increase of atmospheric C02 must be coming more from anthropogenic sources? In other words, it’s worse than we thought!

Chris H

I presume that these 1000 year old “atmospheric” CO2 levels come from gas bubbles in Antarctic ice cores? CO2 is very soluble in water and diffuses very quickly through aqueous solutions. I find it very difficult to believe it hasn’t equilibrated to a very large extent with the air and must, therefore be a very poor reflection of the CO2 level at the time the bubble formed.
Someone please tell me I’m wrong.