From the USA Today SCIENCE FAIR web-site:
Could the best climate models -- the ones used to predict global warming -- all be wrong? Maybe so, says a new study published online today in the journal Nature Geoscience. The report found that only about half of the warming that occurred during a natural climate change 55 million years ago can be explained by excess carbon dioxide in the atmosphere. What caused the remainder of the warming is a mystery.
Well, well, well - could the BEST climate models be wrong?
"In a nutshell, theoretical models cannot explain what we observe in the geological record," says oceanographer Gerald Dickens, study co-author and professor of Earth Science at Rice University in Houston. "There appears to be something fundamentally wrong with the way temperature and carbon are linked in climate models."
The conclusion, Dickens said, is that something other than carbon dioxide caused much of this ancient warming. "Some feedback loop or other processes that aren't accounted for in these models -- the same ones used by the Intergovernmental Panel on Climate Change for current best estimates of 21st century warming -- caused a substantial portion of the warming that occurred during the PETM." (“Palaeocene-Eocene thermal maximum”)
All this in a peer-reviewed Journal -Nature Geoscience.