Ice core update indicates trouble in Greenland
The coldest and highest parts of the Greenland ice sheet, nearly two miles above sea level in many locations, are warming rapidly and showing changes that are unprecedented in at least a millennium, scientists reported Wednesday.
That’s the finding from research that extracted multiple 100-foot or longer cores of ice. The samples allowed the researchers to construct a new temperature record based on the oxygen bubbles stored inside them, which reflect the temperatures at the time when the ice was originally laid down.
“We find the 2001-2011 decade the warmest of the whole period of 1,000 years,” said Maria Hörhold, the study’s lead author and a scientist at the Alfred Wegener Institute in Bremerhaven, Germany. Since warming has continued since that time, the finding is probably an underestimate.
That is bad news for coastlines, because it suggests a longterm process of melting is being set in motion that could deliver some significant, if hard to quantify, fraction of Greenland’s total mass into the oceans. Overall, Greenland contains enough ice to raise sea levels by more than 20 feet.
The study stitched together temperature records revealed by ice cores drilled in 2011 and 2012 with records contained in older and longer cores that reflect temperatures over the ice sheet a millennium ago. The youngest ice contained in that older set of cores was from 1995, meaning they could reveal nothing about temperatures in the years since then.
The research, published in the journal Nature, also found that compared with the 20th century as a whole, this part of Greenland, the enormous north-central region, is 2.7 degrees Fahrenheit warmer.