“The decade from 2001 to 2011 was the warmest of all 1,000 years,” says Maria, lead author of the study and a scientist at the Alfred Wegener Institute in Bremerhaven, Germany. Hörhold says.
And since warming has only continued since then, this finding probably underestimates the extent of climate change. The high-altitude areas of northern and central Greenland have changed. This is bad news for Earth’s coastlines. This is because a long-term melting process is underway, suggesting that eventually a significant fraction of Greenland’s total mass, although difficult to quantify, may be released into the ocean. because Overall, Greenland contains enough ice to raise sea levels by more than 20 feet.
In this study, we stitched together temperature records revealed by ice cores drilled in 2011 and 2012 with records contained in older and longer cores that reflect ice sheet temperatures 1,000 years ago. rice field. The youngest ice in these old cores was from 1995, so we couldn’t tell much about current temperatures.
The study also found that a large area of north-central Greenland is now 1.5 degrees Celsius (2.7 degrees Fahrenheit) warmer than it was throughout the 20th century, with higher rates of ice melt and water loss. Along with these changes, the number of sheets that raise sea levels has increased.
The study was published Wednesday in Nature by Hörhold and a group of researchers from the Alfred Wegener Institute, the Niels Bohr Institute in Denmark and the University of Bremen in Germany.
Isabella Velicogna, a glaciologist at the University of California, Irvine, who was not involved in the study, said the new study “uses data within Greenland to provide an instrument that shows unprecedented warming over recent periods.” It pushes the record back 1,000 years.”
“This doesn’t change what we already knew about signs of warming in Greenland, increased melting, accelerating ice flow to the sea, and the difficulty of slowing this down. “Still, it adds to the seriousness of the situation. This is bad, bad news for Greenland and all of us.”
Scientists hypothesize that if Greenland’s air gets warm enough, a feedback loop will occur. As the ice sheet melts, it loses altitude and is naturally exposed to warmer air, further melting and sinking. Such.
But just because this north-central part of Greenland is 1.5 degrees Celsius warmer than it was in the 1900s, it doesn’t necessarily mean that the ice sheet has reached this feared ‘tipping point’.
Recent research was suggested Greenland’s hazard threshold has been placed at about 1.5 degrees Celsius or more of global warming, which is a different number than the regional warming of the ice sheet. If the average global temperature rises by 1.5°C in the 2030s, Greenland’s warming could be even higher, and warmer than it is today.
Researchers surveyed by the Washington Post also emphasized that the northern regions of Greenland, where these temperatures are recorded, are known to have the potential to cause significant sea level rise for other reasons.
“We should be concerned about warming in northern Greenland because the area is home to 12 sleeping giants in the shape of wide tidewater glaciers and ice flows… Greenland’s contribution to sea level rise‘ said Jason Box, a scientist at the Danish and Greenland Geological Survey.
box published research Last year suggested that in the current climate Greenland is already doomed to lose Amount of ice equivalent to nearly one foot of sea level rise. This committed sea level rise will only get worse as temperatures continue to rise.
Concern is centered on the Northeast Greenland ice current, where most of the ice sheet (12%) flows towards the sea.It is essentially a large, slow river that ends in several very large glaciers that flow into the Greenland Sea. Become thinand the glaciers at their terminus have lost mass – one of them, Zachariae Isstrom, has also lost the frozen shelf that once stretched above the ocean.
Recent research It also shows that during past warm periods in Earth’s relatively recent history (that is, the last 50,000 years or so), this part of Greenland was often less ice-covered than it is today.In other words, the ice flow could extend further outward from the center of Greenland. than can be maintained at the current temperature, There is a strong tendency to retreat and give up a lot of ice.
Beata Csatho, an ice sheet expert at the University of Buffalo, said:
The same year researchers were drilling the ice core that underpins their current work — 2012 — something amazing happened in Greenland. That summer he saw surface melt conditions in much of the ice sheet in July, including the cold and very high altitudes where the study was conducted.
“This was the first year that you were observed melting at these elevations,” Hörhold said. “And it still continues.”
fix
An earlier version of this article stated that the Niels Bohr Institute is located in Germany. Located in Denmark.
