This graph shows Antarctica warming up slightly before atmospheric carbon dioxide rose and well before global temperatures warmed. In a new study, researchers explain that a change in the Earth's orbit resulted in a change in ocean circulation that prompted the Antarctic to warm before the rest of the planet. CREDIT: Jeremy Shakun View full size image 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

read more: Carbon Dioxide Linked to End of Last Ice Age