Global warming: Our best guess is likely wrong
No one knows exactly how much Earth’s climate will warm due to carbon emissions, but a new study this week suggests scientists’ best predictions about global warming might be incorrect. The study, which appears in Nature Geoscience, found that climate models explain only about half of the heating that occurred during a well-documented period of rapid global warming in Earth’s ancient past. The study, which was published online today, contains an analysis of published records from a period of rapid climatic warming about 55 million years ago known as the Palaeocene-Eocene thermal maximum, or PETM.
“In a nutshell, theoretical models cannot explain what we observe in the geological record,” said oceanographer Gerald Dickens, a co-author of the study and professor of Earth science at Rice University. “There appears to be something fundamentally wrong with the way temperature and carbon are linked in climate models.”
During the PETM, for reasons that are still unknown, the amount of carbon in Earth’s atmosphere rose rapidly. For this reason, the PETM, which has been identified in hundreds of sediment core samples worldwide, is probably the best ancient climate analogue for present-day Earth.
In addition to rapidly rising levels of atmospheric carbon, global surface temperatures rose dramatically during the PETM. Average temperatures worldwide rose by about 7 degrees Celsius — about 13 degrees Fahrenheit — in the relatively short geological span of about 10,000 years.
Many of the findings come from studies of core samples drilled from the deep seafloor over the past two decades. When oceanographers study these samples, they can see changes in the carbon cycle during the PETM.
“You go along a core and everything’s the same, the same, the same, and then suddenly you pass this time line and the carbon chemistry is completely different,” Dickens said. “This has been documented time and again at sites all over the world.”
Based on findings related to oceanic acidity levels during the PETM and on calculations about the cycling of carbon among the oceans, air, plants and soil, Dickens and co-authors Richard Zeebe of the University of Hawaii and James Zachos of the University of California-Santa Cruz determined that the level of carbon dioxide in the atmosphere increased by about 70 percent during the PETM.
That’s significant because it does not represent a doubling of atmospheric carbon dioxide. Since the start of the industrial revolution, carbon dioxide levels are believed to have risen by about one-third, largely due to the burning of fossil fuels. If present rates of fossil-fuel consumption continue, the doubling of carbon dioxide from fossil fuels will occur sometime within the next century or two.
Doubling of atmospheric carbon dioxide is an oft-talked-about threshold, and today’s climate models include accepted values for the climate’s sensitivity to doubling. Using these accepted values and the PETM carbon data, the researchers found that the models could only explain about half of the warming that Earth experienced 55 million years ago.
The conclusion, Dickens said, is that something other than carbon dioxide caused much of the heating during the PETM. “Some feedback loop or other processes that aren’t accounted for in these models — the same ones used by the IPCC for current best estimates of 21st Century warming — caused a substantial portion of the warming that occurred during the PETM.”
Source: Rice University
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Nasif Nahle (10:48:17) :
The Missing, forgotten and Only Factor: The Sun.
Well, the orbital elements of the Earth and the distribution of land and oceans [including ocean currents depending on that] are very important factors, even assuming an absolutely constant Sun. Solar variations cannot explain a change in temperature a hundred times larger than the effect of the solar cycle today.
Rhys Jaggar (10:50:41) :
Are there any proxies for solar irradiation indices which can be measured in a similar way for the PETM? Would be interesting to know, wouldn’t it??
Of course, there are some; for example, 10Be, Ca-II, 14C, 36Cl, HSG, Shells, diatoms, foraminifera, teeth, etc. However, it’s not opportune to use them now when sciences as paleontology, paleobiology, paleoclimatology, and paleo-etc., are being “adjusted” through a solipsistic way.
Correction to above: that should be “The paper did NOT model the PETM climate.”
Leif Svalgaard (10:41:41) : I could model warming over the last century with a linear equation, increasing slope, but less in magnitude than any given temp series. I could say my model accounts for part of the warming, but that does not mean my linear model is a good one.
Leif Svalgaard (11:07:23) :
Nasif Nahle (10:48:17) :
The Missing, forgotten and Only Factor: The Sun.
Well, the orbital elements of the Earth and the distribution of land and oceans [including ocean currents depending on that] are very important factors, even assuming an absolutely constant Sun. Solar variations cannot explain a change in temperature a hundred times larger than the effect of the solar cycle today.
I consider those factors just as modifiers; nonetheless, the Sun is the only patent source of energy for climate. Factors like volcanic ash that obstructs the path of sunbeams towards the surface and the modification of albedo by ecological succession are factors which modify climate, but do not produce it. The Sun produces climate. I have said it many times that the external operator of climate on Earth is the Sun; the other factors are just distributors, like the carbon dioxide, and internal modifiers.
Just for comparison, Mercury, the planet, has a very tenuous atmosphere composed of hydrogen and helium which has not an appreciable effect on Mercury’s climate. However, Mercury has an intense climate driven almost exclusively by the Sun, although factors as those that you mentioned modify it. On Earth the thing is different because it has an atmosphere and, most important, water.
@Leif…
On the other hand, if you only could determine and define what the “other” sources of energy besides the Sun or, at least, what the internal producers (not modifiers) of climate are, perhaps the idea on a fixed, static Sun which has nothing to do with Earth’s climate would be more credible.
Tom P (10:52:06) :
The paper did model the PETM climate – the climate sensitivity is directly extracted from the derived values of CO2 injected into the atmosphere and the temperature change from the isotopic ratios.
Then there is the usual confusion about what a ‘model’ is. One type [the one you describe] is a simple determination of or ‘fit’ to [if you will] the sensitivity of the climate to changes of basic parameters. The other type [and that is the one many get confused about] is the ‘general circulation models’ where they run the model decades into the future trying to simulate the evolution of the climate. The latter ones don’t work, the former ones are not too bad.
Nasif Nahle (11:40:40) :
the idea on a fixed, static Sun which has nothing to do with Earth’s climate would be more credible.
The other way around: before you can discount or accounted for all the other sources, you cannot claim that the variable Sun is solely responsible, as you did.
Leif Svalgaard (11:44:08) :
Nasif Nahle (11:40:40) :
the idea on a fixed, static Sun which has nothing to do with Earth’s climate would be more credible.
The other way around: before you can discount or accounted for all the other sources, you cannot claim that the variable Sun is solely responsible, as you did.
If it just were my claim, your assertion would be valid; however, it’s not just an idea, but what nature exhibits. Now I will say what you much hate: Turn off the Sun and see what happens with climate, distributors of energy, internal modifiers, and internal operators. 🙂
Me thinks we need to reissue 5th grade science books. Remember the chapter on on-shore flow of ocean breezes? And then what happens to the moisture in the air as it rises and builds up against the first mountain range it comes to? And then what happens on the other side of the mountain range? Finally, remember what happens when the precipitation returns to the oceans? This process goes a long way in predicting and modeling temperature swings. Any model used to compare with proxy temperatures during these ancient times would have to model this basic weather pattern circulation of what it was BACK THEN. Where where the land masses, what were they like, where were the rivers, where were the cold and warm oceanic currents back then, what was the Coriolis like and how did the trade winds work? Where were the jet streams? Finally, what were the various oscillations like? Then and only then would you even consider adding CO2 levels, methane levels, volcanism, etc to your model of ancient climates and weather pattern variation.
rbateman
“You can’t take a cave with you to follow the herds. Living permanently in a cave says affluent.”
Animals (horses at least) follow great circle routes. Paleolythic Indian hunter-gathers were found to improve the plants they gathered by selective breeding! Yes that is correct Hunter-Gathers planted the seeds from the best to be available to gather next year when they visited the same spot.
If there were caves available I imagine they would be used as shelter and possibly improved. You may not be able to take it with you but you can use it as a vacation home until you hunter out that area.
(from my long time ago anthro course in college)
Nasif Nahle (11:32:41) :
The Sun produces climate.
This is the same, old, tired, worthless argument [turn off the Sun and see what you get]. The Sun produces the energy that allows climate on ALL the planets. The important question is what causes climate variability, and that is hardly the Sun, as already on the Earth orbital changes and surely volcanism produce much larger changes than can be ascribed to the Sun. In fact, we have a hard time proving [to the satisfaction of the AGW crowd – and if we can’t convince them, we don’t have compelling proof] that solar variability has any significant impact.
Gene Nemetz (02:32:58) :
Mal (01:39:56) : “What is not debatable is that human society has allowed far too much burning of fossil fuels in a dirty way, and the world population growth without a way to sustain it is a terrible tragedy.”
I strongly suggest you take a good hard look at Maurice Strong, oil billionaire, and his connections to the Banksters (Rockefeller) who back Greenpeace and Sierra club and the rest. The bankers/oil are manipulating Activists to do their dirty work and will institute a form of Feudalism if they can. If you want to be a serf to the Banksters go find some other country. The USA has close to a zero population growth and we are a heck of a lot cleaner than the socialist country CHINA. A friend in Alaska complains the pollution from China has ruined Alaska’s clean air.
These are examples of your friendly socialist banker advisors such as Maurice Strong at work. He was a top advisor to the World Bank and Rockefeller meets with the World bank often. Actually he trained the World Bank president at Chase.
SAP The globalization of poverty http://www.doublestandards.org/sap1.html
Structural Adjustment Policies http://www.whirledbank.org/development/sap.html
Mr. Budhoo’s Bombshell: Former employee Breaks Code of Silence on IMF of crimes: http://www.thirdworldtraveler.com/IMF_WB/Budhoo_IMF.html
Info on Bank crimes:
http://freedomprime.blogspot.com/2008/08/money-is-created-by-banks-evidence.html
According to Congressional record the U.S. Government can buy back the FED at any time for $450 million. That’s about half the amount of money we pay them daily. http://www.libertyforlife.com/banking/federal_reserve_bank.html
Actual copy of the act (confiscated all US citizens gold) http://www.fame.org/PDF/Emergency%20Banking%20Act%20of%201933.pdf
As an Activist I would hate the thought I was a shill for the corporate/banking ellite.
At first I thought Leif Svalgaard (who is one of the main reasons for me to come to WUWT on a daily basis) was being ironic, but seeing later on in the discussion that he isn’t, has left me feeling a bit uneasy.
I know everybody here is cheering because all they interpret from this article is that models aren’t perfect (as if anybody who means anything has ever said that), and that it’s being said by a respected source, never mind the context. Heck, that’s probably why Anthony placed it.
But there’s another interpretation that casts an entirely different light on this article, the one expressed by Leif Svalgaard. If AGW isn’t a hoax – and if anyone is sure it is, he cannot by definition be a skeptic – then the implications of this article could potentially spell trouble, big trouble. I haven’t read a lot of pieces here at WUWT that debunk the permafrost-and-methane-clathrate-melt scare stories.
What IS this article doing here, Anthony? Have you turned alarmist? 😉
Co2 rising back then was due to the warming, hence the models explain NONE of the natural warming! Outgassing of the sea etc…
As I have always maintained, if the models can not replicate iceages and long term variation they are useless for making projections. They cant even explain why the co2 rose back then in their models! Thats the key, why did the sea warm in the first place, before the co2 rose?
Models need to be tested and proven before used. When people test the GCM’s they fail the test – hence they are of no worth.
Will they now stop using them? I doubt it!
All they need to do is double the climate sensitivty again and factor up the strength of aerosols and they will be happy again, just fudge it. Then they can declare even more drastic warming now predicted based on past historical data! Models are calibrated ever better!
If the authors are thinking that the climate is MORE sensitive to CO2 than thought, based on this article, it should even be able to overcome cooling. In other words, human emission CO2 should be stronger than natural climate variation. Problem is, the current observations do not show that this is the case. If anything, it is showing that natural variability is stronger than human emission CO2. This article and the current cooling trend, in spite of increasing CO2, cannot be reconciled if this super-sensitive response to CO2 is the unspoken meaning of the research.
Leif,
To determine the climate sensitivity at the PETM it is only necessary to divide two numbers, the increase in temperature and the increase in CO2 concentration. This can by no stretch of the imagination be described as running a model or even a fit, so where is the confusion?
Another important point is that the 5 to 9 degC increase in temperature seen at the PETM is likely to have been close to an equilibrium value, with thousands of years to equilibrate to the injection of CO2. The current climate has only had a few decades to respond to most of the anthropogenic CO2 emissions. We could be seeing our future by looking back into the past.
Perhaps the answer to the rapid warming Palaeocene-Eocene thermal maximum and our recent cooling can be easily explained .. LUN
Many thanks to Al Gore’s sister.
Leif Svalgaard (12:06:59) :
This is the same, old, tired, worthless argument [turn off the Sun and see what you get]. The Sun produces the energy that allows climate on ALL the planets. The important question is what causes climate variability, and that is hardly the Sun, as already on the Earth orbital changes and surely volcanism produce much larger changes than can be ascribed to the Sun. In fact, we have a hard time proving [to the satisfaction of the AGW crowd – and if we can’t convince them, we don’t have compelling proof] that solar variability has any significant impact.
And what if the response is gradual, that is, not instantaneous but cumulative? We have observed at least four bodies of the solar system which simultaneously are undergoing climate changes. The local conditions are different for each body, including composition of atmospheres and land surfaces; the effect is there. I am sure you will not evade answering the problem by trying to unlink one planetary climate change from the others referring to local particular planetary conditions. Simultaneity is a hint which guides us to a common cause, whether the changes are identical or not in each planet, planetoid or natural satellite. The only common source of energy for climate in this solar system is… the Sun.
Here’s a theory for the increase in CO2 back in the Paleocene – all those dead and rotting dinosaurs…
(Note too that pollinating plants first eveolved in the early Tertiary – Paleocene. A mate of mine at University had the theory that dinosaurs were killed off by hay fever…)
Come to think about it, maybe that’s were a some of the increase is from these days. Not only are there more people living on the planet than there ever has been, there are more people dying – and hence being converted largely into CO2 – than ever before…
Bill Illis’ graph (18:20:27) does demonstrate a geological disconnect between CO2 and temperature, with only two exceptions: Antarctic Glaciation, and PETM.
From ScienceNOW:
…Zeebe…ran carbon-cycle simulations…They even simulated what would happen to global temperatures when they increased the atmosphere’s sensitivity to doubling CO2 levels…
“It’s possible that other greenhouse gases such as methane could have contributed to the (PETM) warming,” Zeebe says…
Neven,
Indeed. I’ve had a look at the site from time to time but since Stephen Goddard sublimated I haven’t seen too many forays into the mainstream science arena.
This article is rather an exception and might indicate the risks of posting on the basis of a press release before perhaps reading the journal article itself.
Leif, Neven, Tom P et al
“In a nutshell, theoretical models cannot explain what we observe in the geological record,”
Remember: ‘it’s just a model’. (Monty Python and the Holy grail.)
There is a lot of methane, as hydrates, reservoired in shallow ocean sediments – I’ve seen them in wells I’ve worked on offshore in various places around the world. But it’s all natural. Even if it did all escape and cause a climate change it would still not be AGW.
‘And there’s the rub’… (Willie Shakespeare. Was it ‘Hamlet’?)
“Even if it did all escape and cause a climate change it would still not be AGW. ”
Well, that’s a relief!
I ran across a reuters article on this study, and promptly popped over here to see if it was already noted or to mention it if not because reuters interviews lead author Zeebe. Headline is reasonable (knowledge gap). Unfortunately article is anything but reasonable and distinctly uses the faulty logic “tipping point” chicken-little ‘this means things are far worse for us than the worst we’ve considered’ tact. It puts this forward as only possible interpretation, no mention of any alternative view. http://in.reuters.com/article/worldNews/idINIndia-41050320090715?pageNumber=1&virtualBrandChannel=11584
I know here at Wattsup I’m not alone in this, but I don’t anger easily and yet this stuff utterly infuriates me. A major component of that is how grossly flawed an idea the general public winds up with regarding what is or isn’t science and what can or can’t be CONCLUDED or even reasonably speculated on from any particular study.
It FLOORS me that the authors of this study would speculate on the tipping point ‘its worse’ scenario and yet not emphasize just as strongly at the same time that it may also mean that CO2 may not be driving temperatures as commonly believed AT ALL. Floors me enough that I very VERY much hope they did/do, and its the reporters who are skewing the picture. If not, can we immediately revoke those scientist’s licenses and ban them from practice entirely please?
I hope that I might impose on everyone’s knowledge here a little, for some brief answers of things that I fully realize have full books written about them….and a couple of ignorance of the day types.
There’s enough solid science on both sides to argue either that CO2 leads OR lags temperature changes, correct?
If a large number of temp. monitoring stations record data that is at best +/- 2 degrees, and some worse than that, how do they justify 0.x outputs (referring to both post data manipulation and model calculations)?
It seems that the degree of debate over how the base temperature data should be handled/manipulated ought to be more than enough in and of itself to say the science on the issue isn’t far enough along to draw ANY conclusions yet, let alone talk public policy….. am I off base here?
Thanks in advance for your thoughts.