Cape Town - Arctic sea ice coverage this year is the sixth lowest on record, continuing the below-average trend, Nasa scientists have announced.
Ice sheets in the Arctic expand in the northern winter and retreat in the summer. However, with climate change, the retreat in winter is growing. Temperatures in the Arctic have increased at twice the rate as the rest of the globe, with winter temperatures rising more than those in summer.
Walter Meier, a researcher at Nasa’s Goddard Space Flight Centre in Maryland, said this week that, even with the relatively cool year, the Arctic sea ice coverage was the sixth lowest since records began in 1978.
“It is so much thinner than it used to be, it is more susceptible to melting,” he said.
This was despite the fact that the relatively cool summer did not have any of the big storms or persistent winds that could break up sea ice and increase melting.
Nasa reports that while summer sea ice has covered more of the Arctic in the last two years than in the record low summer of 2012, this was not an indication that the Arctic was returning to average conditions. There was a continuing downward trend of the sea ice and the Arctic Ocean was losing about 13 percent of its sea ice every decade.
The Northwest Passage above Canada and Alaska remained ice-bound in the northern summer, but a finger of open water stretched north from Siberia into the Laptev Sea, reaching beyond 85º north – the farthest north open ocean had reached since the late 1970s, Meier said.
Nasa tracks sea ice from space, and also conducts airborne field research to track changes in the ice and its impact on climate. Operation IceBridge flights over the Arctic have been measuring sea ice and ice sheets for several years.
This month Nasa began a new field experiment, called Arise, which explores the relationship between retreating sea ice and the Arctic climate.
Nasa monitors the planet’s vital signs from land, air and space from a fleet of satellites. This data, and long-term records, are analysed by computer-modelling to see how the Earth is changing.
The impacts of dwindling ice cover are far-reaching, from threat to species’ survival, to enhanced global warming, to the weakening or shut-down of global ocean circulation.
Cape Times