El Nino or La Nina? The Past Hints at the Future

摘要

Two teams of researchers, studying the same evidence with the same techniques, have painted diametrically opposite pictures of a key period in the history of Earth's climate, which climatologists are probing for hints of what's to come. "It's a tough issue to sort out," says climate modeler Raymond Pierrehum-bert of the University of Chicago in Illinois. "What's at stake is the regional distribution of climate," both past and future. But he's going to have to wait for more data from the past. The two groups, one British and one American, are studying what temperatures in the equatorial Pacific Ocean were like during the early Pliocene epoch, about 4.5 million to 3.0 million years ago. The world was about 3℃ warmer then than it is today—much as it may be a century or two from now.