Thaindian News

Washington, June 18 (IANS) Carbon dioxide levels explain why temperatures in tropical oceans and arctic waters have changed together for the past 2.7 million years, says a study.
The findings led by a research team of Brown University appear to cement the link between the Ice Ages and temperature changes in tropical oceans.

The research has established that the climate in the tropics over the last 2.7 million years changed with the cyclical spread and retreat of ice sheets thousands of miles away in the Northern Hemisphere.

The research team, including scientists from Luther College in Iowa, Lafayette College in Pennsylvania and the University of Hong Kong, analysed cores taken from the seabed at four locations in the tropical oceans: the Arabian Sea, the South China Sea, the eastern Pacific and the equatorial Atlantic Ocean.

These showed that climate patterns in the tropics have mirrored Ice Age cycles for the last 2.7 million years and that CO2 has played the leading role in determining global climate patterns.

Researchers zeroed in on tropical ocean surface temperatures because these vast bodies, which make up roughly half of the world’s oceans, orchestrate the amount of water in the air and rainfall patterns worldwide, as well as the concentration of water vapour, said a Brown University release.

“We think we have the simplest explanation for the link between the Ice Ages and the tropics over that time and the apparent role of carbon dioxide in the intensification of Ice Ages and corresponding changes in the tropics,” said Timothy Herbert of Brown University.