Dinosaurs Experienced Wild Shifts in Climate

Drastic climate change wasn't always our fault. In fact, wild swings in the average temperature of the Earth were going on in the time of the dinosaurs.

A study based on an analysis of ocean sediment that will appear in the October issue of Geology shows that the climate of ancient Earth was surprisingly fickle. During the Cretaceous period, ocean surface temperatures varied wildly, by as much as 6° C.

We get a switch, from warming then cooling, then warming then cooling, said Simon Brassell, a paleoclimatologist at Indiana University, Bloomington and lead author of the study. It's as if the Earth's climate responds not necessarily gradually, but more like a changing gear in a car. And that's something that many climatologists are concerned about—whether there is some threshold that will lead to us to a very different climate than we're experiencing now.