A “new normal” is settling over the Arctic, experts warned yesterday.
Temperatures are rising, ice is melting, snow is disappearing and the region’s delicate ecosystems are rapidly evolving. It’s already not the same place it was a few decades ago, and it won’t be the same place a few more decades into the future.
That’s the stark conclusion of this year’s Arctic Report Card, an annual update on the Arctic climate from NOAA. The report was released yesterday with a virtual press conference hosted at the annual fall meeting of the American Geophysical Union.
“The report card provides a snapshot in time of a region in the middle of transition,” said Rick Thoman, a scientist at the University of Alaska, Fairbanks, and one of the report’s editors, speaking at the press conference. “Nearly everything in the Arctic, from ice and snow to human activity, is changing so quickly that there’s really no reason to think that in 30 years much of anything will be as it is today.”
Temperatures in the Arctic are currently rising at least twice as fast as the global average. In 2020, the Arctic experienced its second-warmest year on record (Greenwire, Dec. 8).
Meanwhile, the Arctic Ocean is warming, wildfires rage across the tundra each summer, the Greenland ice sheet is melting at accelerating rates and Arctic sea ice is dwindling year over year.
The Arctic Report Card provides a comprehensive look at the ways the region is shifting. These are some of the biggest highlights from 2020.
Shrinking sea ice
Arctic sea ice typically hits its lowest extent in September, at the end of the summer melt season. This year’s minimum was the second lowest on record, just behind the summer of 2012.
Sea ice was especially sparse off the coast of Siberia this year, where spring and summer temperatures were unusually warm. The annual summer melt began earlier than usual—by June, ice cover in Russia’s Laptev Sea had hit a record low for that time of year.
The fall freeze-up also began later than usual. It was late October before sea ice finally began reforming in the Laptev Sea, the latest date on record.
Scientists say the low sea ice extent and unusually warm temperatures formed a vicious cycle this year. Sea ice helps to reflect sunlight away from the Earth—when it melts, it allows more heat to reach the planet’s surface. This year’s early melting likely caused summer temperatures in the Laptev Sea to climb even higher, driving more melting in the process.
This year was a record-breaking summer for wildfires in the Arctic Circle. That’s mainly thanks to a spate of blazes across Siberia, particularly in the Sakha Republic, which borders the Laptev Sea.
According to the Copernicus Climate Change Service, wildfire activity in Siberia had already broken last year’s record by June. High temperatures, and an abundance of dry fuel, were largely to blame.
Arctic wildfire activity often varies widely from one year to the next. But some long-term patterns are emerging.
Large fire seasons—seasons that burn at least 1,900 square miles of land—have become more common in Alaska over the last 40 years. On the other hand, they’ve slightly declined in Canada’s Northwest Territories. Data in Siberia only goes back about 20 years, making it harder to judge a long-term trend.
In general, though, scientists believe that rising temperatures increase the likelihood of drier fuels and more frequent, bigger wildfires.
Much of the dry fuel feeding Arctic blazes comes from dead mosses and other plant matter that build up in the soil. Freezing temperatures tend to prevent these dead plants from fully decomposing over the winter. When the spring thaws out the ground, they rapidly dry out. The warmer the air, the earlier the spring and the faster they may dry.
“As the Arctic Report Card documents, the region is now experiencing some of the most rapid climate warming on the planet,” said Alison York, a fire expert at the University of Alaska, Fairbanks, who spoke at the report’s release. “We all know that fire is more likely and more active in warm, dry and windy conditions, and fire regimes in high northern latitudes do appear to be responding to the warming that’s underway.”
Climate change is affecting plant and animal life in the Arctic Ocean, from the bottom of the food chain up.
Tiny algae form the cornerstone of the Arctic’s marine ecosystem. Each spring, when the sea ice melts and the ocean fills with light and nutrients, the algae begin to rapidly grow. This spring bloom provides an explosion of food for other animals in the Arctic Ocean.
As the Arctic warms and the sea ice thins, these blooms are getting bigger and happening earlier. Scientists also have noticed a second bloom happening in the fall in some places, as the hotter summers delay the autumn freeze-up.
That’s a phenomenon that’s “relatively new,” according to Karen Frey, an Arctic expert at Clark University, who spoke at the press conference.
The extra food is a boon for some animals in the Arctic Ocean. This year’s Arctic Report Card includes a special report on bowhead whales, which have experienced some recent population growth in the Arctic. Scientists believe these increases may be linked, at least in part, to the extra algae.
But it’s not good news for everyone, Frey warned. There are several types of marine algae in the Arctic, including free-floating algae and algae that mainly grow on sea ice. When sea ice melts, the ice algae tends to fall all the way to the ocean floor, where they feed bottom-dwellers like shellfish, sea urchins and sea cucumbers.
Less sea ice could mean less algae for these organisms, Frey warned.
Reprinted from Climatewire with permission from E&E News. E&E provides daily coverage of essential energy and environmental news at www.eenews.net.