Global wind shifts ended last Ice Age?

WASHINGTON: Scientists have claimed that global wind shifts many have ushered in a warmer climate and the birth of human civilisation at the end of the last Ice Age about 20,000 years ago.

An international team has looked to a global shift in winds and propose a chain of events that began with melting of the large northern hemisphere ice sheets about 20,000 years ago, the 'Science' journal reported.

The melting ice sheets reconfigured the planet's wind belts, pushing warm air and seawater south, and pulling carbon dioxide from the deep ocean into the atmosphere, allowing the planet to heat even further. Their hypothesis makes use of climate data preserved in cave formations, polar ice cores and deep-sea sediments to describe how Earth finally thawed out.

"Finally, we have a clear picture of the global teleconnection in Earth's climate system that are active across many time scales.

"These same linkages that brought the earth out of the last ice age are active today, and they will almost certainly play a role in future climate change as well," Bob Anderson at Columbia University, who led the team.

Earth regularly goes into an ice age every 100,000 years or so, as its orientation toward the sun shifts in what are called Milankovitch cycles.

At the peak of the last ice age, about 20,000 years ago, with New York City and large parts of Europe and Asia buried under thick sheets of ice, Earth's orbit shifted.