Climate Change: Greenland Glaciers are Retreating at a Record Pace
Greenland's glaciers may be retreating far more quickly than expected. Scientists have taken a closer look at their historical retreat and have found that over the past century, they've melted at least twice as fast as any other time in the past 9,500 years.
In order to track how glaciers grew and shrank over time, the researchers extracted sediment cores from a glacier-fed lake that provided the first continuous observation of glacier change in southeastern Greenland. Then, the scientists compared the results to similar rare cores from Iceland and Baffin Island.
Glaciers are dynamic and heavy. As a glacier moves, it grinds the bedrock beneath it and creates silt that its meltwater washes into the lake below it. The larger the glacier, the more bedrock it grinds away. In fact, scientists can take sediment cores from the bottom of glacier-fed lakes to see just how much silt settled over time, along with other indicators of a changing climate. In this case, the researchers examined lake cores from Kulusuk Lake.
"If we compare the rate that these glaciers have retreated in the last hundred years to the rate that they retreated when they disappeared between 8,000 and 7,000 years ago, we see the rate of retreat in the last 100 years was about twice what it was under this naturally forced disappearance," said William D'Andrea, one of the researchers, in a news release.
What's interesting is that the pulse of shrinking and cooling matches sediment cores from Iceland and Baffin Island. This suggests that glaciers have responded in sync across the North Atlantic for at least the past 4,000 years.
The findings are published in the journal Climate of the Past.
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