Each December, scientists issue a report card on the Arctic’s ecosystem health. The 17th annual NOAA report, presented today at AGU’s Fall Meeting 2022 in Chicago, features original, peer-reviewed research from 147 authors from 11 nations. The report card emphasized that rain is becoming more common than ever before in many parts of the Arctic. Total annual precipitation—both rain and snowfall—has also been increasing across most of the Arctic since the 1950s.
“We found that total precipitation now shows a statistically significant trend in the Arctic,” said John Walsh from the International Arctic Research Center at the University of Alaska Fairbanks and the lead author of the report’s precipitation chapter. Statistical significance holds true for all four seasons and all data sets used in the report, which are “largely” independent of each other, he said.
Arctic regions around the fringes are already transitioning from snowfall- to rainfall-dominated climates.
Rainstorms that occur when temperatures are hovering near 0°C turn roads into ice rinks and disrupt how easily wild animals can walk through the snow. “In the Arctic, these freezing rain events can be devastating because the ice layer can persist for months until the spring thaw,” Walsh said.
As a result of its continued rise, precipitation amount and type will now be assessed yearly, joining the ranks of temperature, sea ice extent, and five other “vital signs” that scientists interpret each year in the report.
A collection of factors may be causing more rain, said Walsh.
As sea ice melts, wider swaths of open water are exposed for extended periods, making moisture more available to the atmosphere. Another factor could be warmer air in the atmosphere carrying more water. For each 1°C the air warms, it holds 7% more moisture.
Last, storminess in the Arctic may be increasing and causing more rain events. Storms are passing over more open water and warming air on their way to the Arctic, favoring their intensification.
Typhoon Merbok struck the west coast of Alaska in mid-September, damaging or destroying homes, hunting camps, boats, and other subsistence infrastructure, as well as disrupting vital fall subsistence harvests, write the report’s authors.
One morsel of good news accompanied the report: Arctic geese populations are healthy and thriving at or above historical levels. In 2020, the 15th annual report similarly noted that bowhead whales in the Arctic have recovered to nearly pre–commercial whaling numbers.
Other long-term trends have continued.
The Greenland Ice Sheet, a significant contributor to present-day sea level rise, experienced its 25th year of net ice loss, sloughing off 146 gigatons of mass, equivalent to about 0.4 millimeter of sea level rise.
The mercury is still rising throughout the Arctic, according to the report. In 2022, weather stations near the North Pole neared the melting point as air warmed 30°C above normal. Just last week, temperatures in Utqiagvik, Alaska, were 4°C above freezing despite the city being in 24 hours of darkness, said Matthew Druckenmiller, a research scientist at the National Snow and Ice Data Center and lead report editor.
“The wolf is in the house,” said NOAA administrator Rick Spinrad. Warped roads, abnormal fish migrations, Arctic peoples displaced, and longer fire seasons are effects of climate change right now, he said. “That’s just a snapshot of what parts of the lower 48 might expect in the very near future.”
—Jenessa Duncombe (@jrdscience), Staff Writer