Global warming: Our best guess is likely wrong
July 14, 2009
A new study suggests scientists' best predictions about global warming might be incorrect. Credit: Rice University/Photos.com
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 (news : web)
Aug 09, 2006 |
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HA! Wait till I tell the EPA about THIS! Then maybe we can "cap and trade" our greedy excessive use of Oxygen and Nitrogen, too! :-b
From this article it looks like the earth may have warmed for some unknown reason, and Co2 went up from ocean outgassing.
Why are you so eager to believe this article as opposed to other global warming articles..?
Props to my university for this study! RICE! FIGHT! NEVER DIE!
Couldn't possibly put a variable solar output (I.R to X-ray and solar wind) into the failing models.
Blatant lie.
"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."
Blatant lie.
"Doubling of atmospheric carbon dioxide is an oft-talked-about threshold"
Blatant lie.
"and today's climate models include accepted values for the climate's sensitivity to doubling."
Blatant lie.
As scientists, the first and deepest lesson we should have etched into our psyche is that we deal with THEORY and HYPOTHESIS and that FACT only comes afrer repeatable, independently verified experiments over extended periods of time! And even then these "facts" are recognized as only being "accepted fact within the limits of experimental error".
It is astounding to me that we allow our political and emotional sides to go off, half-cocked, when so much is clearly UNKNOWN. We are terrified about today's equivalent of "the population bomb" or the "china symdrome" or the "silent spring" or the "coming ice age".... all predictions of doom that were vastly over dramatized. Observed fact, but here we go doing it all again!
Certainly... we may tomorrow be hit by an unexpected beam of radiation from the sun or a rock wipping this instant from the other side of the sun at half the speed of light. More likely, our earth could up-chuck a major flow of magma, cloud the skys and freeze us all to death.
And frankly, we have little more ability to end global warming through politics than we have of stopping any of those potential disasters!
But as scientists, we MUST demand models that are consistent with the historical record, both short AND LONG, and we must have at least a very healthy level of humility and self criticism before making earth changing predictions....
Unless we are really in it just for the money and we want to get in on the bottom of the "next big thing" .... and THIS is far more likely to be true cause of "global warming" than ANY model published to date!
The more important question is not if you believe CO2 is causing warming. The aspect here is more of a personal nature which asks - whether you feel there is a need for mankind to explore alternative sustained energy sources and maybe in the process reduce dependence on fossil fuels.
But back to the subject, personally I would trust any climate model as much as I trust the 5day forecast.
Whoever thinks that scientists can actually predict anything to do with 'global warming' are sadly self-delusional.
The system that they are trying to 'model' is far, far more complex than any of their simplistic models.
For instance: weather models, that have had far more study done on them, by far more people for a far greater amount of time, and are consequently much more sophisticated, can only predict the weather fairly closely for about 3 days!
Gimme a break!
Scientific thinking isn't restricted to official scientist. And a fact is a fact even if you belong to the plebs.
But I'm curious; do we all have to be geoscientist to be allowed to talk about this subject or is it alright to be a scientist of another discipline?
Al least you disqualify yourself as a scientist with your social engineering response.
J.
As for whether CO2 is causative orcorrelative is outside the scope of the article, as is the warming potential of CO2.
What is inside the scope, and central to the global warming hypothesis is whether the PETM shows evidence of a mechanism (natural or not) that explains warming either with or without carbon chemistry.
I think your thinking is incorrect. The implication of the article is that GW will be WORSE than predicted by 'assumed' CO2 effects, for there is an ADDITIONAL process possibly at work which could augment temperature consequences. This news is bad for the ostrich-people who continue to deny the seriousness of this problem!
3 DAY prediction? Try that in UK and see what happens. The weather report changes from morning to afternoon..let alone 3 days.
Every singe computer simulation of "GloWarm(tm)" has been so sadly mistaken that they cant ever replicate the historical data with any degree if accuracy... stuff that happened! How can you trust that to predict anything?
There's no statement made about the seriousness of the problem or whether it will be worse or better.
But no one pays attention to history, or the Scientific Method, for that matter.
We can't predict the weather a week from now. We'll never be able to do so. Yet Al Gore & Co. predict the weather 40 yeas from now. What a joke.
Actually, the corelation between CO2 and earth surface temperature is explicitly stated in the article. The whole point of it is that when Co2 levels increased at a time 55 million yrs in the past, the temperature increased A LOT MORE than present climate models predict. That's real bad news.
You dummies trying to say we can never ever predict anything in the future because we cannot yet predict weather are pissing me off! How many times do you have to be told. Weather and climate ARE NOT THE SAME THINGS!!! Climate is the AVERAGE of weather across long time periods and large areas. Climate is MUCH more predictable than weather.
Prime example: electric current.
The problem is not the research per se - at least that is the way I see it. The problem is that so many articles quote a study that may or may not indicate that the climate is changing and automatically put that down to Man Made Global Warming without a shred of evidence. If the articles made their point and did not do this there would be less criticism from the deniers.
It is good that people are studying this stuff and models are handy tools (so are some of the modelers). We have to remember that a model is a model of limited value and that the story they tell us has limited benefit.
If we see a few more humble modelers then I think we will see a bit more Kudos to the modelers.
The only way to tell who is wrong or right, is to know the entire truth and i dont know anybody that does that.
I think its great that someone wants to find out how our planet is working and has the courage to take on a task of that immense size. Every bit of information helps build the big picture, criticism makes people withhold information. Whats tricky is the intent behind the information. I've heard a sentence often used in science is "publish or die", is that how we want science to work for us?
http://www.projec...2_08.pdf
Some pretty crazy ideas there eh? lol
It may be much more predictable but they haven't been able to predict the last 30 years, or in this case, a period 55 million years ago.
Predicting historic climate is the Holy Grail of climate models because they can be checked against what is already know. If they can't do that they have no basis to claim the ability to predict future weather.
Recent research has shown that better methods for modeling climate (than GCM) may exist:
http://www.wisn.c...ail.html
From my own point, as a software engineer, finding that some people in the US government and the IPCC have admitted that the quality of the climate models is a complete unknown is an indication that they may be starting in the direction of validating the quality of the software before waving the results about like some kind of revelation.
Don't you have some cartoons to watch??
So what will be the mean temperature of the earth next year? Since it is so easy to predict...
We already know you do not understand the science, len. Proof of that was in your comments in another thread that use of Ethanol would not reduce CO2 levels.
1000 years ago the Arctic climate was at least 4° to 5°C higher than today, and perhaps more. We know this because of a number of findings in Greenland (deep graves dug 1000 years ago with hand tools which are frozen solid today, historical records of people swimming in waters off Greenland whereas temperatures today would assure a quick hypothermic death, species of fish near the shores that are not present today, species that do not like water as cold as at present, crop pollens, etc.) and in places ranging from Alaska to Norway.
There was not a massive melting of the GIS or flooding coastlines like the gloom and doom Gorians say will happen. And, yet, CO2 was not at the root of the rise in temperatures 1000 years ago, or even 2000 years or so ago during the Roman Warm Period.
The article is right. We do not know enough to make the sorts of gloom and doom predictions that are being made, based on faulty models and misreading of the data, not to mention failure to look into the facts of history and prehistory.
I absolutely agree. Climate is much more "chaotic" than, say, the orbital mechanics of the Solar system. I do not find it surprising that it is hard to come up with a computer model that can explain the changes 55 million years ago, based on our incomplete knowledge of how the climate worked back then.
For instance, since we obviously lack exact measurements of trace gasses or seasonal temperature variations, we have to rely on "proxy" measurements of preserved indirect traces that do not necessarily have a 1:1 relation to what we really want to measure. Getting the CO2 level or temperature wrong to the extent mentioned in this article (as opposed to being wrong by a factor of 10) is probably no disgrace.
Being aware of the flaw is in itself exciting news, now climate modellers can go ahead and search for the subtle causes that has thrown the existing paleoclimate models off track. The experience can then be applied to models of the current climate.
Guys, this article is saying that human-induced global warming could be *worse* than we thought. It's *not* an argument against human-induced global warming. From the article:
In other words, there could be more feedback loops that will make global warming even worse than we thought. This says nothing about humans being blameless. Please read the article before commenting on it.
As for the PETM, yes, the warming preceded the CO2 increase, and yes, that means the PETM was not initiated by CO2. And no, that does not prove that global warming today is caused by something other than CO2. Geez.
It also states that our current models, the only evidence for AGW, do not take all factors into account. It states our knowledge of the climate system is lacking. And it makes no statement about warming and CO2 relationships outside of the basis GHG statement.
The only thing the article says is "we don't know".
Which is exactly what our point is. Read all the comments before commenting.
It goes up and it goes down - can't we just f***ing deal with it? I'm so goddamn tired with all this back and forth B.S. from both sides! NONE of you has a f***ing clue one way or another. The hubris in thinking that we can exist outside of our environment or adapt it to whatever arbitrary climate we think is "perfect" is insane.
You will find that many people are happy or at least willing to drop stuff into the oceans or the upper atmosphere just to cool the planet down or warm it up depending on what part of nature they don't like.
I remember going to church groups when I was young and hearing that man has the god-given right to do whatever he wants.