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Ice Core Studies Confirm Accuracy of Climate Models
13 September 2008
An analysis of the global carbon cycle and climate for a 70,000-year period in the most recent Ice Age shows a strong correlation between carbon dioxide levels and abrupt changes in climate.
The findings, published 11 September in the online edition of the journal Science, shed further light on the fluctuations in greenhouse gases and climate in Earth’s past, and appear to confirm the validity of the types of computer models that are used to project a warmer climate in the future, researchers said.
We’ve identified a consistent and coherent pattern of carbon dioxide fluctuations from the past and are able to observe the correlation of this to temperature in the northern and southern hemispheres. This is a global, interconnected system of ocean and atmosphere, and data like these help us better understand how it works.
—Prof. Ed Brook, Oregon State University
The analysis was made by studying the levels of carbon dioxide and other trace gases trapped as bubbles in ancient ice cores from Antarctica.
In the last Ice Age, as during most of Earth’s history, levels of carbon dioxide and climate change are intimately linked. Carbon dioxide tends to rise when climate warms, and the higher levels of carbon dioxide magnify the warming, Brook said. These natural cycles provide a “fingerprint” of how the carbon cycle responds to climate change.
The level of atmospheric carbon dioxide today is about 385 parts per million, or more than double that of some of the lower levels during the Ice Age. These changes have taken place at a speed and magnitude that has not occurred in hundreds of thousands of years, if not longer. Past studies of ice cores have suggested that Earth’s temperature can sometimes change amazingly fast, warming as much as 15 degrees in some regions within a couple of decades.
Before humans were affecting the Earth, what we are finding is regular warm and cold cycles, which both began and ended fairly abruptly. This study supports the theory that a key driver in all this is ocean currents and circulation patterns, which created different patterns of warm and cold climates depending on the strength of various parts of the global ocean circulation system.
—Ed Brook
One of the primary circulation patterns is the meridional overturning circulation. When that current is moving large amounts of warm water from the equator to the north, it helps to warm the high latitude parts of the Northern Hemisphere, and particularly the North Atlantic region. When the system stops or dramatically slows, as it has repeatedly in the past, Greenland and Europe get much colder while the Antarctic regions become warmer, Brook said.
In every historic sequence we observed, the abrupt warming of Greenland occurred about when carbon dioxide was at maximum levels. And that was during an Ice Age, and at levels of atmospheric carbon dioxide that are far lower than those we have today.
—Ed Brook
Resources
Jinho Ahn and Edward J. Brook (2008) Atmospheric CO2 and Climate on Millennial Time Scales During the Last Glacial Period. Science DOI: 10.1126/science.1160832
September 13, 2008 in Brief | Permalink | Comments (28) | TrackBack (0)
Comments
Posted by: agwtruth | September 15, 2008 at 12:21 PM
Aym:
Your arguments represent what is called “appeal to authority” fallacy. Over the centuries science suffered badly from reliance on authority, rather than on prediction-verification method.
Returning to falsifiable predictions, there were couple of non-trivial falsifiable predictions generated by GHG warming effect hypothesis. All physical models of GHG effect predict presence of so-called GHG signature – pocket of abnormally hot air in upper troposphere-lower stratosphere over the tropics. There is no such pocket. It is already enough to falsify basic physics of atmospheric GHG effect, which is (as rightfully pointed out by agwtruth) not properly described in scientific literature, to put it mildly.
Another failed AGW prediction is polar amplification of warming, which did not happen in Antarctica, where such effect should be much more pronounced than in Arctic.
There are more mortal flaws of AGW hypothesis, like pronounced global cooling in 1940s-1970s, when antropogenic CO2 emissions really picked up, or fabled 500 year lag between warming and increase in atmospheric CO2 concentrations. Such two flaws demonstrate that CO2 could play only MINOR role in global climate.
Posted by: Andrey Levin | September 16, 2008 at 12:27 AM
I doubt very much that your own appeal to authority is any better. Frankly looking up so-called facts from sites that spout authoritative so-called nonsense facts that you can use in arguements is very much worse.
Antarctic variations in temperature might be attributed to ozone depletion. There may be others. The idea that it doesn't exist or is explained doesn't negate AGW.
The constant use of CO2 levels being the only component to climate is bull. AGW is the mainstream idea of climate that includes CO2 and is not dependent on it. The idea that CO2 doesn't contribute to climate is nonsense since if the very idea of a radiative body in homeostasis would put the earth at an average of -18C when it is 15C.
As for the cooling effect. That may well have been the result of global dimming from pollution. A well known physical effect.
Posted by: aym | October 03, 2008 at 11:25 AM
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"It is of no little significance that the IPCC’s value for the coefficient in the CO2 forcing equation depends on only one paper in the literature; that its values for the feedbacks that it believes account for two-thirds of humankind’s effect on global temperatures are likewise taken from only one paper; and that its implicit value of the crucial parameter κ depends upon only two papers, one of which had been written by a lead author of the chapter in question, and neither of which provides any theoretical or empirical justification for a value as high as that which the IPCC adopted."