Could we be wrong about global warming?

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.

"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 article in USA today is here.