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
If you build models to look for anthropogenic influences then you will get models that do just that. What has been clear for some time is that the influences on climate are way more tricky than the simple forcing the AGW folk seem so attached to. I still reckon Joe Weizenbaum had it spot on (he wrote his book Computer Power and Human Reason after witnessing the behaviour of humans in using a simple model of a Rogerian counselor) when he wrote:
What is important in the present context is that models embody only the essential features of whatever it is they are intended to represent. … What aspects of reality are and what are not embodied in a model is entirely a function of the model builder’s purpose. But no matter what the purpose, a model, and here I am concerned with computer models of aspects of reality, must necessarily leave out almost everything that is actually present in the real thing. Whoever knows and appreciates this fact, and keeps it in mind while teaching students about the use of computers, has a chance to immunize his or her students against believing or making excessive claims for much of their computer work.
(Weizenbaum 1984, xvii)
Weizenbaum, J. (1984). Computer Power and Human reason. From Judgement to Calculation. Harmondsworth, Middlesex: Penguin.
Could the sudden upsurge in temperature have been caused by a massive release of methane hydrates caused by tectonic/volcanic activity (or whatever)?
The reason is because there were no climate models during te PETM. Mann and Schmidt et. all would have worked the numbers into shape had they been around to do so.
Whether or not the “Global Warming” models are correct is clearly debatable. 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.
“gtrip (23:51:05) :
What dreadful hot weather we have! It keeps me in a continual state of inelegance.
Jane Austen (1775-1817) English novelist, author of “Sense and Sensibility”
What a nice way to say ‘sweating like a pig!
cheers David
UK Sceptic (01:11:44) :
There are other mechanisms at work. It is more complex than methane and co2.
You may like to watch the 5 part series in YouTube to see one mechanism that is recently becoming very interesting.
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.
Why is this not debatable?
Mal (01:39:56) :
What you are saying would be a matter of opinion, wouldn’t it?
This is what is wrong with the models:
The article says this :
“A climate that is highly sensitive to radiative forcing (i.e., responds very strongly to increasing greenhouse gas forcing) by definition will be unable to quickly dissipate global mean temperature anomalies arising from either purely natural dynamical processes or stochastic radiative forcing, and hence will have significant internal variability. The opposite also holds.”
I wholly concur but what do we see ?
Despite huge changes in the rate of energy emission from the oceans and consequent attempts by the oceans to change global humidity the hydrological cycle keeps global humidity almost stable by altering the speed of it’s activity through adjustments of the sizes and positions of all the main circulation systems.
The climate is therefore seen to be highly INsensitive to attempts at forcing by huge changes in the primary greenhouse gas.
Applying the same logic it must also be highly INsensitive to attempts at forcing caused by extra CO2.
The same mechanism would apply in both cases but to deal with CO2 the necessary adjustments would be too small to measure in the face of natural variability because the real forcing agent is the oceans and not the air.
Rob (20:23:02) :
None of this matters.
It’s settled.
Al Gore simply wants global governance.
And why would Al want that? First President of the World? I suppose it would make him feel better about coming second in the US a few years ago.
Whoops,
The quote was from this article but is relevant here:
http://www.realclimate.org/index.php/archives/2009/07/warminginterrupted-much-ado-about-natural-variability/
The universe is essentially a creative process. Simply being alive is a creative process. And billions of humans are a creative process. Part of creativity is destruction and transformation and unexpected leaps forward. Some people were against the industrial revolution. Some people were against the Enlightenment. Some people were against the new religions. Some people would rather be pagans living in small tribes, for the “community” spirit.
We do have problems, but we’re also in a creative process. It is not that nobody realises the problems of world hunger and population. The problem is those who believe you solve overpopulation by reducing population. The problem is those who believe you solve energy shortages by making energy more expensive, and limiting its supply.
You’ve heard the old joke about how the medical procedure was a complete success but the patient died?
And just to add, we don’t have the right to tell Africans that they can’t have children, or to tell Indians that they can’t have children, or cars, or whatever it is they want. We do no have the right to tell them to stop developing.
Once they have developed enough, they will in their own time change their needs and wants, and nobody is going to make them do otherwise.
“2) I expect RC to be in FULL DEFCON 1 RETALLIATION/DAMAGE CONTROL tomorrow….
And who would notice?”
Excellent point, Gene….
As several posters have pointed out, it all comes down to cause and effect. The 70% increase in CO2 may well have occurred simply because the oceans warmed and released vast quantities of CO2. By the way, does anyone know how much additional atmospheric CO2 would be caused by a 7 degree rise. There are indications that the CO2 increase occurred several thousand years *after* the temperature increase started. Just as with the ice cores, this strongly suggests something very simple and yet extraordinarily important: that CO2 changes are primarily an effect and not a cause.
Many dramatic climate changes (e.g. the end of Snowball Earth) have been attributed to CO2 (in the case of Snowball Earth, the assumption that large volcanic eruptions released enough CO2 to warm the earth). But is there any *proof* that the CO2 caused the warming and not the other way around? Probably the only way to prove it is to demonstrate that the CO2 increased *before* the warming started. The ice cores clearly show that CO2 was an effect, and not a cause, but it must be far harder, if not impossible, to achieve the same time resolution for events tens or hundreds of millions of years ago.
If this evidence does not exist, then probably the simplest assumption is that changes in CO2 were largely driven by temperature changes. Therefore, to explain the temperature changes we need to look elsewhere.
As far as I can see, this study is consistent with the anti-AGW hypothesis: that carbon dioxide has a negligible effect on the climate.
Finally, I’ll repeat a question I’ve asked several times before. So far there’s been no answer.
Is there any period in earth’s history when it can be proven that the global temperature was driven by carbon dioxide? (and not the other way around).
Chris
Gene Nemetz – Thanks. 🙂
Hi Chaps;_)
I am getting rather tired of saying this, but you’re next! I know this is OT, but thought you would like a wheese at the nutty fruitloop UK, or Disney Land as I like to call it. I have received in this morning’s post a document from a company called Z-led, based in Nottingham, UK. They provide design solutions to ground gas migration. I suspect you’re ahead of me on this one, but yes dear old CO2 is catagorised under new Government guidelines as a “Toxic” and “asphyxiating” gas! Now I know the context in which they are operating as I have worked on radon/methane protection systems in the past & still occasionally do, but this is how it will go for you. We have an organisation paid for by the Building Industry called the National House Building Council (NHBC). We also have a prtofessional group know as the Building Research Establishment (BRE) part industry part governemnt funded. They have obviously been re-doing their little courses & now include CO2 in the tables. It has a maximum allowable safe volume of 5%!!!!!!!!!!! not 0.04% as it is inthe atmosphere. However note 3 does say higher levels are permitted should the Site Model (whatever that is?) says it is safe to do so!
Now we’ve known about CO2 in this instance for ages, but it is just the way it is presented here (www.z-led.com) that makes me suspiciously laugh.
AtB
Francis, UK Sceptic,
From the paper:
“Different sources for the carbon input have been suggested, which has led to speculations concerning the mechanism. Some, such as volcanic intrusion, imply that the carbon drives the warming. Others, such as the destabilization of oceanic methane hydrates, imply that the carbon release is a feedback that can exacerbate warming.”
The results in this paper do not depend on the initial source of the release and do not rely on any climate modelling. As I showed, though, they appear consistent with the upper range of equilibrium climate sensitivities seen in the current models. It appears that a CO2 release 55 million years ago, of the similar order of magnitude as that seen from anthropogenic sources over the last fifty years, produced a 5 to 9 degC rise in temperatures.
“Those who do not learn from history are doomed to repeat it.”
Forgot to add, the 5% limit is calssified as the GREEN safe traffic light zone in the tables!
Leif, check TTY´s link about PETM:
http://igitur-archive.library.uu.nl/dissertations/2006-0906-200913/index.htm
“Hence, sea surface conditions characteristic of the PETM, including extreme warming, initiated significantly prior to the injection of 12C-enriched carbon. This implies that this injection likely occurred as a result of global change, rather than the other way around, and invokes the dawn of the next challenge: solving the question how global change, including warming, could occur without a change in the isotopic composition of the exogenic carbon pool . ”
Another thing, pointed out above is, that PETM heating was linear around 0,07 Kelvin/century and this was with 70% CO2 increase, we only have 33% CO2 increase today.
So less than 0,07 K / century, how does it fit models predicting 2 – 7 Kelvin?
Ive heard that due to Earths fuels deposits, we should no be able to get higher than 485 ppm CO2. If so, we will max get a level around the 70% increase seen in PETM.
K.R. Frank
Correction: It should say “IF the petm warming was linear”.
so what’s the problem, you guys would not be arguing if you ‘knew’ you were correct. to stay the same is impossible, the world is changing with or without your blessing. No amount of skepticism can ‘stop’ the reality of what really happens. so what if politics can’t solve the issue, the earth will, like or not.
“Whether or not the “Global Warming” models are correct is clearly debatable. 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 trage”
The 2 foundation stones of the Enviormental Left in recent decades has been Anthropological Climate Change and Unsustainable Population Growth. These 2 issues have driven not only pop science but much of our international and domestic politics. In recent years, both subjects have come under more and more scrutiny, and lo and behold, the Left is wrong on both counts.
Funny how reality usually sets in after policies have been put in place. In Europe, the governments there are finally realizing that they don’t have enough people to sustain neither thier generous social welfare state nor thier standard of living. In the US, where were are about to officially tackle Antrhological Global Warming, we are finally realizing that there has been no warming for about a decade (this despite the antics of GISS and NOAA. Both are becoming irrelavant).
As the globe slowly but steadily cools, and much of Europe, Russia, and Asia begins to depopulate (North America is not too far behind in that respect), more and more people are finding out that a)It is much more pleasant and efficient to live in a warm world, and b)society actually needs people to if it wants to improve its way of life.
I know farmers here in Northen Indiana aren’t especially happy with the propescts of lower crop yields this year, and a few pundits around here are even calling 2009 a year without a summer. The last time we had such a cool June-July was 1992 (the year after Mt Pinutumbo went off). This could be the first year since 1901 that this area will see a summer where the temperature failed to reach 95, and had less than 5 days with temperatures above 90.
Mal (01:39:56) :
Whether or not the “Global Warming” models are correct is clearly debatable. 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.
—
Please exactly specify any single measureable “bad thing” that increasing the CO2 levels in the atmosphere actually has done. Can do. WIll do.
Please name any members in a free population measureably worse off with our recent increase in affordable energy over the past 120 years. Please name the members of the world (of a free society!) worse off now compared to 120 years ago. (Note: You cannot include despostic, ignorant and tribally-led corrupt dictators in free societies. At worst however, even these tribally-led, communistic and corruptly-led peoples are still better off than before.)
240 years ago.
480 years ago.
Drudge picked up the story