Arctic sea ice cover falls🖤😢 to 'alarming' low as temperatures rise
Change affects more than 70 indigenous communities around the Bering Sea
Change affects more than 70 indigenous communities around the Bering Sea
Arctic sea ice cover fell to its second lowest level on record this summer, continuing a “dramatic” downwards trend that is disrupting marine ecosystems and making life for indigenous people in the region ever more precarious.
(NOAA) annual report card on the state of the Arctic found that the average annual air temperature was 1.9C above the long-term average, taken from 1981 to 2010, the second highest it has been since observational records began in 1900.
The warmer conditions meant that ice froze later in the winter and melted sooner in the summer, reducing the extent of Arctic sea ice at the end of the summer to the second lowest level since satellites began monitoring ice coverage 41 years ago.
On 18 September 2019, when the sea ice was at its minimum, it covered 4.15m sq km, a 33% drop and more than 2m sq km smaller than the long-term average minimum for the time of year.
“It’s more alarming each year that we have this situation,” said Perovich, a co-author on the report and professor of engineering at Dartmouth Col in N Hampshire. “I approach every report card with a sense of trepidation: is this going to be the year we have another big decrease?
“When we look at the end-of-summer ice extent, the 13 smallest years have all been in the past 13 years. There was a large decrease in 2007 and we have never returned to the levels before that,” he added.
The greatest amount of Arctic sea ice was observed on 13 March 2019, with end-of-winter coverage extending over 14.78msq km, down 5.9% on the long term average maximum, and the seventh lowest in the satellite record.
The oldest ice, which is more than four years old, once dominated the Arctic, but now makes up a mere fraction of the ice pack. In March 1985, old ice accounted for 33% of Arctic sea ice, but only 1.2% in March this year.
“Overall, the Arctic sea ice cover has transformed from an older, thicker, and stronger ice mass in the 1980s to a younger, thinner, more fragile ice mass in recent years,said the report, which was unveiled on Tuesday at the American Geophysical Union conference in San Francisco.
In Greenland, a summer heatwave produced melting on a par with the worst years ever, with satellite data from 2002 to 2019 showing that the ice sheet has lost on average about 267bn tonnes of ice per year.
The Arctic is particularly vulnerable to the climate crisis, with annual air temperatures rising twice as fast as the global average.
Part of the reason is that sea ice reflects the sun’s rays back out to space, and as it melts, a feedback cycle kicks in whereby retreating ice exposes more sea water which absorbs more heat and drives more melting.
The warming temperatures are already disrupting life for more than 70 indigenous communities that live around the Bering Sea, where sea ice narrowly missed setting a record low this year.
Hunting on the ice is becoming more hazardous and access to subsistence foods is shrinking, the report’s authors found. As the region warms, Arctic fish species are retreating to more northerly waters.
