Science / Medicine : Global Cooling May Have Killed Dinosaurs

In the continuing search for the ancient culprit that killed the dinosaurs, scientists said last week that it may have been neither meteors nor volcanism but possibly the effects of massive global cooling.

Research geologist Lowell Stott and James Kennett of UC Santa Barbara told the Geological Society of America that such a major climatic shift apparently preceded the dinosaurs’ demise.

Stott and Kennett concluded that global cooling led to the extinctions after analyzing icy cores drilled from the Weddell Sea in Antarctica that essentially held in suspended animation the composition of ancient air that once pervaded Earth.

Another prevailing idea suggests that they became extinct after a series of extraterrestrial objects bombarded primordial Earth, causing dust and debris to blanket the upper atmosphere.

But Stott said that because his evidence suggests that the climatic shift preceded the extinction period 65 million years ago, this would tend to rule out the possibility of extraterrestrial objects waylaying the planet from on high.