May 7, 2012
Julia

An increase of carbon dioxide in the atmosphere preceding the last defrost

London, England – The increased concentration of carbon dioxide in the atmosphere of the Earth may be a cause of rising temperatures that led to last thaw. An international team of scientists, led by American, Jeremy Shakun, has reached this conclusion after analyzing the causes of melting, which began 15,000 years ago and ended 12,000 years.

Previously, the data obtained of ice cores from Antarctica had hinted the relationship between carbon dioxide and temperature rise, but left no clear involvement of CO2 in the evolution of glacial cycles. Experts differed if carbon dioxide had a role in the last thaw, and if their influence was secondary or even if it was a result of melting rather than its cause.

This latter hypothesis is the fact that the Antarctic thermal growth began two thousand five hundred years before it began to concentrate carbon dioxide in the atmosphere. According to the study authors, led by scientist at the University of Harvard, Jeremy Shakun, this variation is due to fluctuations in temperature between the two hemispheres and questions the role of carbon dioxide at the end of the last ice age.

An analysis of 80 planktonic microorganisms on the planet who still have thermal data at the time, concluded that although there were other factors that favored regional Earth warming, the only thing that affected the entire land area was the increase in CO2.

Among the causes that helped also included solar radiation warming, rising sea levels or decrease in the ice sheet that covered the Earth. These researchers say that each of the two phases of thermal growth that occurred in the last thaw, the first 17,000 years ago and the second 12 thousand years ago, were preceded by a remarkable growth of carbon dioxide.

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