Fifteen years of gradation of the impact of warming in the Arctic have left one thing very clear: climate change has drastically altered the Arctic in that short period of time.
Breaking unfortunate records is “like hitting a mole,” says Jackie Richter-Menge, a climate scientist at the University of Alaska Fairbanks and editor of the Arctic Report Card 2020, released Dec. 8 at the American Geophysical Union’s virtual meeting. From sea ice lows to temperature highs, records are popping up everywhere. For example, in June a maximum temperature of 38 ° Celsius (100.4 ° Fahrenheit) was recorded in the Arctic Circle (SN: 23/06/20). And in 2018, winter ice in the Bering Sea has been reduced to a minimum of 5,500 years (SN: 03/09/20).
“But honestly, the biggest title is the persistence and solidity of the warm-up,” says Richter-Menge. In 2007, just one year after the first Arctic Report, summer sea ice reached an all-time low, falling to an area of 1.6 million square kilometers less than the previous year. Then, just five years later, the bulletin noticed a new low, 18 percent below 2007. In 2020, sea ice did not set a record, but not for lack of attempts: it was still the second lowest recorded in recent years. 42 years.
“The transformation of the Arctic to a warmer, less icy and biologically modified region is well under way,” the report concludes. And it’s changing faster than expected when researchers launched the newsletter in 2006. The average annual air temperature in the Arctic is rising two to three times faster than the rest of the globe, says Richter-Menge. Over the past 20 years, it has warmed at a rate of 0.77 degrees C per decade, compared to the global average of 0.29 degrees C per decade.
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Improvements in research techniques over the past 15 years have helped researchers look more closely at the impact of warming and how different aspects of climate change in the Arctic relate. These improvements include the ability to measure ice mass using gravity measurements taken by the Gravity Recovery and Climate Experiment (GRACE) satellite. Other satellites provided additional observations from above, while field measurements, such as the Multidisciplinary Drifting Observatory for the Study of the Arctic Climate (MOSAiC), provided close-up sea ice measurements (SN: 4/8/20). The report also began to include field observations of Arctic indigenous peoples, who are experiencing these changes directly (SN: 12/11/19).
The changes revealed few bright spots, but one is the bounce of bow whales, which were hunted almost to extinction around the 20th century. While researchers are careful to observe that whales remain vulnerable, the four populations of whales (Balaena mysticetus) now range from 218 in the Okhotsk Sea to 16,800 in the Bering, Chukchi and Beaufort Seas. Researchers suggest that the rebound of whales is due, at least in part, to the warming that has occurred over the past 30 years. The earlier melting of sea ice and warmer surface water means more krill and other foods for these bullet feeders.
Nature Picture Library / Alamy Stock Photo
But don’t be fooled. Possible good news is overshadowed by bad news. Mark Serreze, a climate scientist at the National Snow and Ice Data Center in Boulder, Colorado, who did not participate in this year's report, produced "this accumulation of knowledge and ideas we have gained over 15 years." The 2020 research is “an exclamation point about the changes that have been unfolding,” he says. "Pointed whales are doing well, but that's all."