The Arctic Is Becoming Wetter and Stormier, Scientists Warn
Between October 2021 and September, air temperatures above Arctic lands were the sixth warmest since 1900, the report card said, noting that the seven warmest years have been the last seven. Rising temperatures have helped plants, shrubs and grasses grow in parts of the Arctic tundra, and 2022 saw levels of green vegetation that were the fourth highest since 2000, particularly in the Canadian Arctic Archipelago, northern Quebec and central Siberia.
A new chapter in this year’s report deals with Arctic precipitation. Measuring snow, rain and freezing rain is tricky there: In the northernmost reaches of the region, there aren’t many weather gauges. Those that are in place might not measure snow accurately because of windy conditions.
Instead, scientists have begun combining direct measurements with sophisticated computer modeling to get a fuller picture. These methods have given them confidence to say that precipitation levels have increased significantly in the Arctic since the mid-20th century. This year was the region’s third wettest since 1950, the report card said.
Because of warmer temperatures, however, extra snow doesn’t necessarily remain on the ground. Snow accumulation in the Arctic was above average during the 2021-22 winter, the assessment said. But by June, snow cover in the North American Arctic was the second-lowest on record. In the Eurasian Arctic, it was third lowest.
Three main factors could be increasing precipitation in different parts of the Arctic, said John Walsh, a scientist at the International Arctic Research Center of the University of Alaska Fairbanks, and an author of the report card. First, warmer air can hold more moisture. Second, as sea ice retreats, storms can suck up more open ocean water.
Indicators of sea ice rebounded this year after near-record-lows in 2021, but they were still below long-term averages, the assessment found. March is typically when the ice is at its greatest extent each year, September its lowest. At both points this year, ice levels were among the lowest since satellites have been making reliable measurements.
The third factor is that storms are passing over warmer water before reaching the Arctic, feeding them with more energy, Dr. Walsh said. The remnants of Typhoon Merbok traveled over unusually warm water in the north Pacific in September before pummeling communities along more than 1,000 miles of Alaskan coast.