“We found 2001-2011 to be the warmest decade of the entire 1,000-year period,” said Maria Hörhold, lead author of the study and a scientist at the Alfred Wegener Institute in Bremerhaven, Germany.
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And since warming has only continued since that time, the finding is likely an underestimate of the amount of climate in . the high altitude areas of northern and central Greenland have changed. It’s bad news for the planet’s coastlines, because it suggests a long-term melting process is underway that could eventually release some significant, if difficult to quantify, fraction of Greenland’s total mass into the oceans. Overall, Greenland contains enough ice to raise sea levels more than twenty feet.
The study combined temperature records revealed by ice cores drilled in 2011 and 2012 with records contained in older, longer cores that measured temperatures over the ice sheet millennia ago. The least ice contained in these larger cores had been since 1995, meaning they couldn’t tell much about the temperature today.
The work also found that compared to the entire 20th century, this part of Greenland, the north-central region, is now 1.5 degrees Celsius (2.7 degrees Fahrenheit) warmer, and the rate of melting and loss of water ice. The sheet—which raises sea levels—is ultimately increased by these changes.
The research was published in the journal Nature on Wednesday by Hörhold and a group of researchers at the Alfred Wegener Institute, the Neils Bohr Institute in Denmark, and the University of Bremen in Germany.
The new research “repeated the 1,000-year record using data from inside Greenland that shows recent warming,” said Isabella Velicogna, a glaciologist at the University of California at Irvine who was not involved in the research.
“This is not going to change what we already know about the sign of warming in Greenland, the increase in melting and the accelerated flow of ice into the ocean, and that this must be challenged to slow down,” Velicogna said. He added, however, the importance of the matter. This is bad, bad news for Greenland and for all of us.”
Scientists hypothesized that if the air over Greenland warmed enough, a loop would follow: The melting of the ice would cause it to slump to a lower altitude, which would naturally expose it to warmer air, which would cause more melting and sliding; and so on.
That this part of central North Greenland is now 1.5 degrees Celsius warmer than in the 1900s does not necessarily mean that the ice sheet has reached this feared “tipping point”.
Recent research has suggested that Greenland’s dangerous threshold is set at around 1.5 degrees Celsius or higher in global warming – but it’s a different picture than the regional warming ice sheets. When global average warming reaches 1.5C, which could happen as early as the 2030s, Greenland’s warming will be higher than that – and higher than it is now.
Researchers consulted by The Washington Post also highlighted that the northern region of Greenland, where these temperatures were recorded, is known for other reasons to have the potential to trigger a large sea level rise.
“We are concerned about the warming of northern Greenland, because that region has twelve sleeping giants in the form of very wide ocean tides and ice streams … which has stimulated the contribution of the sea to Greenland,” said Jason Box, a scientist with the Geological Survey. Denmark and Greenland.
A box of research published last year suggests that in the current climate, Greenland is already destined to be lost a mass of ice equivalent to nearly a foot of sea-level rise. This level of sea level rise will only get worse as temperatures continue to warm.
Attention is focused on the Greenland Ice Sheet, which pulls the majority — 12 percent — of the ice sheet toward the sea. It is essentially a large, slow-moving river that terminates in several large boulders that empty into the Greenland Sea. It is now thinner, and the mountains have lost mass at their end – one of them, Zacharias Isstrom, has also lost the ice sheet that once extended above the ocean.
Recent research has also shown that during earlier warm periods in Earth’s recent history (that is, the last 50,000 years or so), this part of Greenland often held less ice than it does today. In other words, the stream ice extends farther from the center of Greenland than can be sustained in the current temperatures and be strongly inclined to move backwards a lot of ice.
“Paleoclimate and modeling studies suggest that northern Greenland may be particularly vulnerable to climate warming,” said Beata Csatho, an ice sheet expert at the University at Buffalo.
In the same year that the researchers were drilling the ice cores on which the current work is based — 2012 — something remarkable happened in Greenland. That summer, in July, huge parts of the ice sheet saw their surface conditions disintegrate, in the cold and very high places where the research was done.
The first year it was observed that you melt at these elevations,” says Hörhold. “And now it goes on.”
An earlier version of this article stated that the Neils Bohr Institute was in Germany. It is Denmark.
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