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Greenland's ancient temperatures revealed

Bo Vinther, co-author on the study, is preparing an ice core for visual inspection.
[Credit: Christian Morel]

Researchers studying the last deglaciation, when Earth's ice sheets were beginning to melt, now know more about the temperature of Greenland at that time, thanks to a new report. For years, studies have suggested that Greenland started warming up later than the rest of the Northern Hemisphere--about 14,700 years ago instead of about 19,000 years ago, when the deglaciation began.

But, Christo Buizert and colleagues now provide evidence that Greenland's ice sheets did, in fact, start melting about 19,000 years ago, along with the rest in the Northern Hemisphere. The researchers used measurements of nitrogen isotopes in the ice from different parts of Greenland, rather than the water isotopes that previous studies had relied upon.

Their results provide a clearer picture of Greenland's temperatures between 14,700 and 19,000 years ago. They show that temperatures changed more dramatically in central Greenland than in northwest Greenland, which also suggests that the circulation of the Atlantic Ocean played a role in the timing of these events.

The last deglaciation is the best example of recent, large-scale climate change and understanding how it worked may help researchers to better understand climate change today. In light of their findings, Buizert and his team suggest that abrupt climate changes like this are largely related to the winter season.