Amplification of Global Warming by Carbon-Cycle Feedback Significantly Less Than Thought, Study Suggests
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:
- 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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Thanks for the heartiest laugh I’ve ever had on the Internet!
As lubos motl stated, this eliminiates 80% of the carbon cycle feedback, which makes up 40% of all feedback. In sum it means a reduction of the modeled temperature increase due to the elimination of this single previous error by 1/3.
However, this is probably still an overstatement, as the authors used the discredited hockeystick reconstructions. these are known to underrepresent hoistorical climate variations what in essence means, feedback is still overstated.
I wonder if it’s nitrous oxide. (That’s what’s used in cans of compressed whipped cream.) W00T?
Bart (20:57:14) :
Epicycles. Yes, of course, that’s it. How else is the sky supposed to fall out in chunks unless it’s held in place by a glass sphere that Anthropogenic C02 will inexorably weaken faster than previously imagined?
Really, they should hire the writer’s of ABC’s Lost. At least they make the story a bit believable.
Chris H,
Check this site:
http://www.biomind.de/realCO2/
Very interesting and supports your (and mine) reservations on CO2 retention in ice.
Next “-gate” perhaps?
Excellent web site
http://www.biomind.de/realCO2/
I am beginning to grasp the science, I think. Temperature goes up by one degree every time the CO2 atmospheric level doubles. Ergo, if I back track then every time that CO2 halves, one degree is lost. Ergo, if carbon cap kicks in, and if carbon cap works much better than expected, then I shall be looking for volunteers to help me shovel more coal on to the fire.
Ron Dean (20:56:48) :
John, can you please elaborate on this point? How does this study show this?
I’m not sure how I need to elaborate. There are a few who have speculated that the CO2 rise is a result of the temperature rise rather than from the burning of fossil fuels. As the temperature rise has been less than 1 degree then it cannot be responsible for more than, say, 20 ppm of the ~100 ppm rise we’ve seen since ~1850.
It perhaps encouraging to see some literature published that opens new questions but the fact this paper relies on the very proxy data of Jones , Mann and the team that were used to “prove” the hockey stick , I instantly doubt its rigeur or value.
If the amount of co2 released from natural sources due to temp rise is a fifth of what was previously guessed then they will conclude even more of the residue is anthropogenic; more of the global warming is AGW and cutting CO2 emissions can be even more effective that predicted.
Here is a much less speculative approach to determine the natural / fossil ration of CO2:
http://folk.uio.no/tomvs/esef/esef5.htm
>>
The isotopic mass balance calculations show that at least 96% of the current atmospheric CO2 is isotopically indistinguishable from non-fossil-fuel sources, i.e. natural marine and juvenile sources from the Earth’s interior.
>>
http://www.woodfortrees.org/plot/esrl-co2/isolate:60/mean:12/scale:0.2/plot/hadcrut3vgl/isolate:60/mean:12/from:1958
Here is a plot of short term CO2 and temp variation (long term trend removed). There is a high correlation but the lag of about 1 year in the CO2 response shows that it is the effect and not the cause if the two are linked. (Equally this could show they are both effects of some other factor or its all just a coincidence).
It is already accepted science that on the millennial scale CO2 lags by around 800 yrs and that CO2 rise is the effect and not the cause of temperature change. So on what time-scale is this relationship inverted to become the controlling factor of world climate?
The other corollary of the paper at the subject of this thread is that if there is less quantity of CO2 emmitted as a feedback mechanism the climate sensitivity must be even higher. This contrary to most indications the all the climate models are currently (probably grossly) over estimating that sensitivity.
Any way, in the coming months I think we will see a surge of papers showing diverging conclusions now that the taboo on critisising AWG has been broken.
It also seems likely that Phil and Mickey will not be solicited quite so often to review journal submissions.
Let the real climate science begin…
One of the first things I noticed during my conversion was the relationship between global T and CO2 as seen here http://www.esrl.noaa.gov/gmd/ccgg/trends/
I never expect natural cycles to be in lockstep and was surprised at how close this comes (modulated, as ever, by my pet gripe of granularity);
year ppm/yr
1959 0.95
1960 0.51
1961 0.95
1962 0.69
1963 0.73
1964 0.29
1965 0.98
1966 1.23
1967 0.75
1968 1.02
1969 1.34
1970 1.02
1971 0.82
1972 1.76
1973 1.18
1974 0.78
1975 1.10
1976 0.91
1977 2.09
1978 1.31
1979 1.68
1980 1.80
1981 1.43
1982 0.72
1983 2.16
1984 1.37
1985 1.24
1986 1.51
1987 2.33
1988 2.09
1989 1.27
1990 1.31
1991 1.02
1992 0.43
1993 1.35
1994 1.90
1995 1.98
1996 1.19
1997 1.96
1998 2.93
1999 0.94
2000 1.74
2001 1.59
2002 2.56
2003 2.29
2004 1.56
2005 2.55
2006 1.69
2007 2.17
2008 1.66
2009 1.72
I’m sorry, but this paper is no more acceptable than some of the work carried out by the ‘team’. There is still an awful lot of arm waving and very little empirical evidence.
I am an ignoramus on climate matters but got interested in the claims of climate experts about the warming of the earth and the role of CO2 in that process and am left with some questions I cannot explain.
Our atmosphere consists for 99% of nitrogen and oxygen, 0.93 % argon and besides that quite small permillages of other gases among which CO2 with 0.038 % that is 38 particles CO2 per 100,000 other particles. These 38 are considered responsible for the warming of the earth because they block the radiation of heat from earth to space. The impact of the sun and all the other 99.96 % gases are left out because man has no influence on them. Man is, however, accountable for only 6% of these 0.038 % that is 0.6 x 0.00038= 0.000228 so 22.8 particles per 1,000,000 other particles. An impact which is negligible. It is already very hard for me to believe that 38 particles per 100,000 could have such an enormous influence on temperature fluctuations on mother earth let alone that man with his paltry 22.8 particles per million can exercise any influence at all.
Another issue: does CO2 increase cause temperature rise or does temperature rise cause CO2 increase? The formation of CO2 is a chemical reaction. Chemical reactions proceed faster in higher temperatures so that undoubtedly CO2 will increase with temperature and so there will be a correlation which does, however, not imply that CO2 is the primary source of (any possible but not certain) global warming.
John Finn (02:59:43)
John, what you premise here does not sound unreasonable but I do wonder how the el niño waters at 2°C and above affect these emissions of CO². Remember that most outgassing will be from the oceans and not the land, I am somewhat in the dark as to how ‘global temp anomoly’ can be used to define the rate and quatity of outgassing. What do you think ?
“”” Leif Svalgaard (20:38:50) :
John Blake (20:10:06) :
there can be no, repeat NO, valid model of planetary atmospheric processes, any more than Newton’s “three-body problem” is solvable regardless of spurious numerical precision.
And yet, we solve easily Newton’s N-body problem [N much larger than three] to any desired high precision in our calculations of an Astronomical Ephemeris or of the orbit of a spacecraft. Be careful about drawing analogies like that [they better be correct…]. “””
There’s also no solution to the problem of the circumference of an arbitrary ellipse.
Yet just as Leif says WRT the classical three body problem, the only thing lacking is a closed form solution. Anyonewho wants answers to an actual real situation can calculate one to any required level of precision..
And Gaia doesn’t have any problem keeping the Trojan Asteroids in place in the orbit of Jupiter for quite long periods of time; and the eliptic integrals serve the needs of ellipse circumnavigators.
Then there is Earshaw’s Theorem that says there is no point of static equilibrium for a point charge in an electrostatic field; or words to that effect. That doesn’t stop one from controlling charges dynamically.
But back to your original assertion that there is no valid model of planetary atmospheric processes; we know that isn’t true, because Gaia has just such a model operating right here on planet Earth. There’s a difference between existence, and our complete knowledge of same.
John Finn:
Check this before you go too deeply into rising CO2 levels:
http://www.biomind.de/realCO2/
This paper was based on temperature reconstructions. Therefore its conclusions are only valid for those reconstructions. Since the reconstructions used were mainly prime hockey sticks, any conclusions drawn from their computer jiggery-pokery are completly useless.
I thought all studies which include the now discredited cru which links to all other similar data must be considered garbage.
I thought all studies which include the now discredited cru data which links to all other similar data sets must be considered garbage.
Excellent another peer-reviewed paper,
500 Peer-Reviewed Papers Supporting Skepticism of “Man-Made” Global Warming
P Solar (03:58:26) :
As I many times tried to explain: the amount of human CO2 in the atmosphere indeed is only a few %, as about 20% of all CO2 in the atmosphere is replaced by CO2 from vegetation and oceans, due to seasonal exchanges. Even so, that doesn’t explain the increase, as a mere exchange doesn’t change the total quantity in the atmosphere. And there it is: humans have added over 200 ppmv of CO2 in the past 160 years, and that is the cause of the bulk of the increase of over 100 ppmv. According to the article, the increase in temperature since the LIA of about 1 C is good for only 8 ppmv of the 100+ ppmv increase. Thus even if only 4 % of the current CO2 molecules in the atmosphere is from human origin, over 92% of the increase in total quantity is due to human emissions.
That doesn’t influence the sensitivity of temperature for CO2, it only reduces the expected increase in temperature, as less CO2 is fed back due to higher temperatures.
E.M.Smith (20:12:11) :
Isn’t Hawaii under that yellow band in the Pacific Ocean? Doesn’t that mean that the Hawaii record is NOT representative of the planet (since there is all that blue…)? Doesn’t the picture state clearly that CO2 is “not well mixed” in the air? Isn’t that a fundamental assumption in a lot of the modeling being done?…
The figure is only a one-month average. And one need to look at the scales: the seasonal changes, mainly by vegetation and mainly in the NH give a cycle of +/- 8 ppmv at Barrow, +/- 5 ppmv at Mauna Loa and +/- 1 ppmv at the South Pole. For yearly averages, the differences within the NH are within 1 ppmv and between the NH and the SH less than 4 ppmv, with near equal trends. That is because 90% of the emissions are in the NH and the ITCZ slows down the exchanges of air (and CO2) between the hemispheres. See:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/co2_trends.jpg
re John Finn (15:00:45)
“This isn’t the the main “feedback” effect. That comes in the form of increased atmospheric water vapour, i.e. CO2 warms atmosphere -> warmer atmosphere can hold more moisture. A result from the Climate models is that relative humidity remains constant. If correct concentration of IR absorbing water vapour in the atmosphere will increase.”
“… a result of the Climate models is that relative humidity remains constant”
You have stated that part backwards about humidity in Climate models. The models ASSUME constant relative humidity.
What seems like a simple assumption is actually a strong (but false) forcing factor in the models. As you noted above, warmer atmosphere can hold more moisture. The models – to maintain the requirement of constant relative humidity – then FORCE water vapor into the model’s atmosphere.
Actual measurements show that atmospheric humidity has actually trended DOWN over the past few decades. That to me is one of the stronger arguments against the Climate models.
Dave
Dan (05:24:16) :
John Finn:
Check this before you go too deeply into rising CO2 levels:
http://www.biomind.de/realCO2/
Dan, read this before you believe Beck’s data:
http://www.ferdinand-engelbeen.be/klimaat/beck_data.html
>>
stephen richards (04:25:49) :
I’m sorry, but this paper is no more acceptable than some of the work carried out by the ‘team’. There is still an awful lot of arm waving and very little empirical evidence.
<<
Your first clue should be that Nature published the paper. The paper must be in the AGW camp for that to happen. Your second clue is that the paper assumes CO2 controls temperature. I think many here believe the paper is based on a false premise.
Jim
davidmhoffer (19:37:13) :
an LWIR ray is absorbed after 10m or so if it is in the absorption band of CO2.>
sorry Dirk, misunderstood your point. I may be getting in over my head here, but… if an LWIR hits a CO2 molecule, the temperature of the CO2 molecule goes up. Now the CO2 molecule starts radiating energy because it is hotter than was before. The energy it radiates has two options. It can go downward, in which case it hits either another molecule in the atmosphere or else earth’s surface. The second option is that it goes sideways or up, in which case it will either hit another molecule or escape into space. If it hits another molecule…
A molecule has three temperatures, translational (the ‘normal’ T), rotational and vibrational, under normal atmospheric conditions they are all the same. When a molecule such as CO2 absorbs a photon its vibrational and rotational temperatures are elevated, left to its own devices the molecule would radiate away that excess energy and all three temperatures would again be the same. However the molecule in the lower atmosphere experiences about 10 billion collisions/sec with other molecules so that the excess energy is lost before the molecule has time to radiate it away. It is only in the upper atmosphere where the collision rate is much lower that radiation starts to become the primary mode of energy loss.