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- New research shows that north-central Greenland experienced the highest temperatures between 2001 and 2011 over a 1,000-year period.
- Scientists came to this conclusion after reconstructing climate conditions over the last millennium by analyzing ice cores from the Greenland ice sheet.
- This study can provide a foundation for future studies on ice melt and sea level rise, the authors say.
Collecting core samples from the Greenland ice sheet is no easy task. During a recent expedition, scientists and drilling experts boarded a ski-equipped aircraft and flew to a site at an elevation of about 3,000 meters (9,800 feet) above sea level in central-north Greenland. Then they drilled into the ice sheet with special equipment and packed the extracted cores into insulated boxes that they loaded into the plane’s cargo hold.
“It’s tedious work and it’s difficult to get to these places,” says Bo Møllesøe Vinther, a physicist at the Niels Bohr Institute in Denmark, who was involved in similar expeditions. “The weather has to be very good for you in order to be able to do this.”
Back at the lab, a team of scientists analyzed the isotopic composition of the ice cores to help reconstruct climate conditions on the ice sheets over the last millennium — from the year 1000 to 2011. In a new study published in Nature, they contend that the years between 2001 and 2011 were the warmest during this thousand-year period, and that the region is now 1.5° Celsius (2.7° Fahrenheit) warmer than the long-term average.
“We show that the impact has reached even the most remote areas in Greenland that you can go to,” Vinther, a co-author of the study, tells Mongabay. “So that’s, of course, bad news. But you can say it’s not too surprising.”
The melting of Greenland’s ice sheet could have a dramatic impact on the global climate system. Scientists say that changes in the ice sheet can disrupt ocean circulation, impact weather patterns, and raise sea levels, which, in turn, can increase coastal erosion and storm surges. It’s estimated that sea levels have already risen by 21-24 centimeters (8-9 inches) since 1880 — and levels are expected to continue rising in line with greenhouse gas emissions. In a business-as-usual scenario, experts expect the melting of the Greenland ice sheet to raise sea levels by about half a meter (20 in). When combined with the expected melting of the Antarctic ice sheets, rising seas could envelop island nations and inundate coastal cities, transforming the world as we know it.
Thomas Laepple, study co-author and professor at the Alfred Wegener Institute (AWI) for Polar and Marine Research in Germany, says that while the study doesn’t directly provide new findings on sea level rise, it generates a foundation for future studies on ice melt and sea levels. However, he says that from a melting viewpoint, the team’s observations seem to suggest that sea level rise would be “on the upper range of what models are predicting.”
“It’s not a good sign, in this case,” Laepple tells Mongabay.
Warming in central-north Greenland is also a concern for local communities, Vinther says.
“People that sustain themselves from hunting and are dependent on sea ice to do so run into problems,” he says, “because they have more and more times during a year where the sea ice is not really usable for transportation and then you can’t go to the hunting grounds, and so on and so forth. So for Greenland, it’s important to document that no, this is not normal.”
Vinther says the study only includes results up to 2011 due to the difficulties and practicalities of collecting enough core samples to obtain a statistically significant data set. However, he says the team plans to continue obtaining and analyzing more data on Greenland’s ice sheets.
Andy Aschwanden, a glaciologist and climate scientist at the University of Alaska Fairbanks, who was not involved in the Nature study, calls the research “carefully crafted and scientifically sound,” with findings that are “in line with other studies.”
“This is the first representative temperature record for central and north Greenland covering 1,000 years up until 2011,” Aschwanden tells Mongabay in an email. “Reconstructions from deep cores end in 1950 and the reconstruction resulting from the earlier North Greenland Traverse [core-sampling expedition] ends in 1995. However, many climate related records have been shattered since 1995, and this study clearly shows that central and north Greenland are no exception.”
Laepple of AWI says the study provides a “confirmation of the concerns” experts have about climate change and the melting of Greenland’s ice sheet.
“The findings provide very strong and independent evidence … that we’ve now left the natural envelope and we have strong warming over Greenland,” Laepple says. “Yeah, this is very concerning.”
Hörhold, M., Münch, T., Weißbach, S., Kipfstuhl, S., Freitag, J., Sasgen, I., … Laepple, T. (2023). Modern temperatures in central–north Greenland warmest in past millennium. Nature, 613(7944), 503-507. doi:10.1038/s41586-022-05517-z