The coldest and highest parts of the Greenland ice sheet are warming rapidly and undergoing changes that haven’t been seen in at least a millennium, scientists say.

At least that’s the conclusion of the study after extracting several ice pillars 30 meters or more in length from the second largest ice sheet in the world.

The samples allowed the researchers to compile a new temperature record based on oxygen bubbles stuck in icewhich show the temperatures that prevailed when these ice sheets formed.

“We found that the decade 2001-2011 was the warmest in the entire 1,000-year period,” said Maria Horholdt, lead researcher at the Alfred Wegener Institute in Bremerhaven, Germany.

Since temperatures have continued to rise since then, this discovery probably does not fully reflect how much the climate has changed in the higher regions of northern and central Greenland. This is ominous data for the shores of the planet, because it is assumed that a long melting of ice began, which could force a significant part of them out of Greenland into the oceans. In total, there is enough ice in Greenland to raise sea levels by more than six meters.

The study combined temperature data found by ice cores recovered in 2011 and 2012 with older and older core records that reflect temperatures over the ice sheet from a millennium ago. The most recent ice contained in these old cores dates back to 1995.

The study also showed that compared to the entire 20th century, this part of Greenland, northern and central, is now 1.5 degrees Celsius warmer, and that the rate of ice melt and water release (which raises sea levels) is increasing accordingly.

The study was published today in the journal Nature by Horhold and a team of researchers from the Alfred Wegner Institute and two other institutions in Germany, the Niels Bohr Institute and the University of Bremen.

A new study is supplementing the records with data from the past 1,000 years using data from Greenland, which shows unprecedented rise in temperature over the last period said Isabella Veligonia, a glaciologist at the University of California.

Weligonia was not involved in the research but, looking at the results, comments that they do not change what we already knew: what is happening in Greenland can hardly be slowed down. “This is bad news for Greenland and for all of us.”

Some scientists estimate that if the air over Greenland warms enough, a feedback loop will kick in: melting the ice sheet will bring it down to a lower altitude, exposing it to warmer air, which in turn will cause further melting and falling. and so on.

However, the fact that northern and central Greenland is now 1.5 degrees Celsius warmer than it was in 1900 does not necessarily mean that the ice sheet has reached this dire tipping point.

When the temperature of the entire planet rises by 1.5 degrees Celsius (on average), which could happen even in the 2030s, the increase in temperature in Greenland is likely to be even greater.

Researchers interviewed by the Washington Post noted that the northern region of Greenland, where such temperatures have been recorded, is known to cause significant sea level rise for other reasons.

“We should be concerned about the warming in northern Greenland, because in this area there are twelve “sleeping giant” glaciers and an ice stream that, if wake up they will amplify Greenland’s influence on sea levels,” said Jason Box, a scientist at the Geological Survey of Denmark and Greenland.

Last year, Box published a study suggesting that, based on the current climate, Greenland would gradually lose a volume of ice theoretically equivalent to a 0.3 meter sea level rise. And growth will only get worse as temperatures continue to rise.