CO2 linked to end of last ice age

(LiveScience)The circumstances that ended the last ice age, somewhere between 19,000 and 10,000 years ago, have been unclear. In particular, scientists aren't sure how carbon dioxide, a greenhouse gas, played into the giant melt.

New research indicates it did in fact help drive this prehistoric episode of global warming, even though it did not kick it off. A change in the Earth's orbit likely started of the melt, setting off a chain of events, according to the researchers.

The ambiguity about the end of the ice age originates in the Antarctic. Ice cores from the continent reveal a problematic time lag: Temperatures appeared to begin warming before atmospheric carbon dioxide increased. This has led scientists to question how increasing carbon dioxide — a frequently cited cause for global warming now and in the distant past — factored into the end of the last ice age. Global warming skeptics have also cited this as evidence carbon dioxide produced by humans is not responsible for modern global warming.

But the data from Antarctica alone offer too narrow a perspective to represent what was happening on a global scale, according to lead study researcher Jeremy Shakun of Harvard University.