Prof finds: Ice sheet collapse ushered in colossal ancient drought - 2011-02-25

ICE SHEET COLLAPSE USHERED IN COLOSSAL ANCIENT DROUGHT
Paul Smith’s College professor publishes article in Science linking the two

CONTACT: Kenneth Aaron, Director of Communications
(518) 327-6297 / kaaron@paulsmiths.edu

One of the worst droughts in the past 50,000 years was probably connected to ice sheet collapse and melting at the end of the last Ice Age, Paul Smith’s College Prof. Curt Stager has found.

Stager’s findings, which show possible ramifications for a warming planet, were published Thursday in the online version of the journal Science.

Based on sediment cores collected from lakes as well as dozens of other geological records from most of Africa and southern Asia, the international team of paleoclimatologists headed by Stager documented a centuries-long drought that struck tropical monsoon regions 16,000 to 17,000 years ago—about the same time an influx of icebergs and meltwater surged into the North Atlantic. This is the first study to show how exceptionally widespread and severe the drought was.

The drought likely brought deep-seated change to Stone Age societies affected by it, disrupting migration patterns and reducing populations. Lake Victoria, the world’s largest tropical lake, dried out during the episode; the other major feeder of the Nile, Lake Tana in Ethiopia, also went dry. The Nile, Congo, Indus and other major rivers were all affected.

The exact causes of the so-called “H1 megadrought” are still in question. But its timing suggests that it was somehow linked to the addition of ice and meltwater into the North Atlantic when the planet was emerging from the last Ice Age.

That sudden deglaciation caused temperatures in Europe and much of Asia to drop, thereby disrupting climate systems that brought seasonal rains to Africa and southern Asia. Those systems worked by wicking moisture from oceans during hot summers, and returning the water as rain. When temperatures cooled, the moisture never made it into the atmosphere.

The research was sponsored by the National Science Foundation and other international research organizations.

Could climate change today lead to such a cataclysmic drought again?

“Hopefully not,” says Stager, who notes that not nearly as much unstable ice remains within range of the critical North Atlantic region today. “But it would certainly have been an important chapter in early human history, and one that hasn’t been fully recognized yet.”

ABOUT PAUL SMITH’S COLLEGE



At Paul Smith’s College, it’s about the experience. Our programs, in fields including hospitality, culinary arts, forestry, natural resources, entrepreneurship and the sciences, draw on industries and resources available in our own backyard while preparing students for successful careers anywhere.