Changes in orbit cause ice ages

Press, 7 December 1976, Page 25

Changes in orbit cause ice ages

PA-Reuter New York

Three scientists say they have confirmed an 80-year-old theory that ice ages are caused by changes in the earth’s orbit round the sun. They have discovered that the length of climatic cycles measured in cores taken from the seabed matched the length of cycles in changes of the earth’s orbit.

Their finding, confirming a theory once championed by the Yugoslav, Milutin Milankovich, will be published in the December 10 issue of the journal “Science.”

The three men are Professors James Hay, of Columbia, and John Imbrie, of Brown University, Rhode Island, and Dr Nicholas Shackelton of the

sub-department of quaternary research at Cambridge University. They assembled an uninterrupted record of the earth’s climate over 450,000 years — three times longer than had been done previously — and took their seabed cores from a point midway between Africa, Australia. and Antartica, in the southern Indian Ocean They say the earth is now in one of its warmest periods, after the last great North American ice age 18.000 years ago. And they predict that there will be extensive glaciation and cooler climates in the Northern Hemisphere over the next 20.000 years, although both natural and man-made effects might modify the climate in the short fun.