Snow cover and sea ice continued to be below average. In April, the volume of sea ice in the Arctic Ocean was the lowest since records started being kept in 2010, the assessment's authors reported. Sea ice helps slow warming by reflecting most of the sunlight that strikes it.
Arctic sea ice this year was also thinner than in recent years, the researchers said. Thinning ice has driven growth in shipping traffic, and with it a rise in garbage and noise pollution that could be affecting the movement of marine mammals.
In the Eurasian Arctic, snow cover this June was the third lowest since records began in 1967, the scientists said. This has increased the potential for wildfires such as the ones that have ravaged Siberia the past few summers.
The Greenland ice sheet, which covers about 650,000 square miles and is already one of the fastest-melting ice chunks on Earth, experienced three "extreme melt" episodes this summer, the researchers reported. At the sheet's frigid summit in August, it rained for what is believed to be the first time.
More than 110 scientists from 12 nations contributed to the latest Arctic Report Card, which was presented Tuesday in New Orleans at the annual meeting of the American Geophysical Union.
Changing conditions at the top of the world can have cascading effects farther afield, said Gabriel J. Wolken, a research scientist at the University of Alaska Fairbanks and the lead author of the report card's chapter on glaciers and permafrost.
Melting glaciers can cause sea levels to rise worldwide. And the Arctic's frozen soils store large amounts of carbon. As permafrost thaws, this carbon could be released into the air, accelerating global warming.
That is on top of the increased likelihood of landslides that glacial retreat and thawing permafrost bring about within the Arctic. In Alaska a few years ago, a slope failure at the edge of a glacier sent millions of tons of rock into a bay, producing one of the tallest documented tsunamis.
The authors of this year's report card emphasised that the Arctic region's residents were directly experiencing the impacts from all of these shifts. In recent years, the researchers have begun seeking the input of local Indigenous communities in producing the assessment.
"These changes are not abstract," said Richard L. Thoman, a climate specialist at the University of Alaska and another editor of the report. "It's not just about polar bears. It's about actual human beings, members of the world community that are being impacted now."
This article originally appeared in The New York Times.
Written by: Raymond Zhong
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