The Arctic is experiencing a multi-year stretch of unparalleled warmth “that is unlike any period on record,” according to the 2018 Arctic Report Card, a peer-reviewed report released Tuesday morning from the National Oceanic and Atmospheric Administration, an agency within the United States Department of Commerce.
A vicious cycle
The Arctic has been warmer over the last five years than at any time since records began in 1900, and the region is warming at twice the rate as the rest of the planet, scientists said Tuesday.
The rising air temperatures are having profound effects on sea ice, and on life on land and in the ocean, the scientists said. The changes can be felt far beyond the region, especially since the changing Arctic climate may be influencing extreme weather events around the world.
Those assessments were part of the latest “Arctic Report Card,” issued by the National Oceanic and Atmospheric Administration, a federal agency, and presented Tuesday at a meeting of the American Geophysical Union in Washington.
“We’re seeing this continued increase of warmth pervading across the entire Arctic system,” said Emily Osborne, lead editor of the report and manager of NOAA’s Arctic Research Program. “That’s having implications for both ocean and terrestrial systems.”
The new edition of the report, which is published annually, does not present a radical break with past installments, but it shows that troublesome trends wrought by climate change are intensifying. Air temperatures in the Arctic in 2018 will be the second-warmest ever recorded, the report said, behind only 2016.
Susan M. Natali, an Arctic scientist at Woods Hole Research Center in Massachusetts who was not involved in the research, said the report was another warning going unheeded. “Every time you see a report, things get worse, and we’re still not taking any action,” she said. “It adds support that these changes are happening, that they are observable.”
The warmer Arctic air causes the jet stream to become “sluggish and unusually wavy,” the researchers said. That has possible connections to extreme weather events elsewhere on the globe, including last winter’s severe storms in the United States.
The jet steam normally acts as a kind of atmospheric spinning lassothat encircles and contains the cold air near the pole; a weaker, wavering jet stream can allow Arctic blasts to travel south in winterand can stall weather systems in the summer, among other effects.
The more rapid warming in the upper north, known as Arctic amplification, is tied to many factors, including the simple fact that snow and ice reflect a lot of sunlight, while open water, which is darker, absorbs more heat. As sea ice melts, less ice and more open water create a “feedback loop” of more melting that leads to progressively less ice and more open water.