JOIN USArctic ice melt may halt temporarily: Study
A new model by researchers at the National Centre for Atmospheric Research (NCAR) predicts that Arctic ice, which has been declining for roughly three decades, may stabilise in the next 10 years or so, meaning no additional melting, or even expand.
“One of the results that surprised us all was the number of computer simulations that indicated a temporary halt to the loss of the ice,” said study researcher Jennifer Kay, a NCAR scientist.
“The computer simulations suggest that we could see a 10-year period of stable ice or even an increase in the extent of the ice,” Kay was quoted as saying by LiveScience.
According to the researchers, the fate of sea ice over the next decade depends not only on human activity but also on climate variability that cannot be predicted.
But while temporary weather conditions could boost Arctic ice, the long-term trend is not so rosy, they reported in the journal Geophysical Research Letters.
“When you start looking at longer-term trends, 50 or 60 years, there’s no escaping the loss of ice in the summer,” Kay said, adding that “the long-term fate is basically sealed if we continue to increase greenhouse gas concentrations in the atmosphere.”
Studies have shown that the extent of summertime ice in the Arctic has shrunk by about a third since 1979. This July set a new monthly record low in Arctic ice cover, and scientists have warned that Arctic summer ice could be a thing of the past within decades or by the end of the century.
The new study, the researchers said, confirmed that the losses of Arctic ice in the late 20th century can’t be explained by natural climate variability alone.
They used a computer model called the Community Climate System Model and verified that the model can indeed capture the ice ebbs and flows already observed in the real world.
About half of the summer ice loss between 1979 and 2005 can be explained by natural variability, the team found, while the other half is due to human greenhouse emissions.
Next, they simulated possibilities for future climate, plugging in different levels of greenhouse gases under varied natural conditions.
They found that under current climate conditions Arctic ice is just as likely to expand as it is to contract over the next decade, depending on wind patterns and other difficult-to-predict variability. A warming climate muddles that short-term picture.
“The changing Arctic climate is complicating matters,” Kay said. “We can’t measure natural variability now because, when temperatures warm and the ice thins, the ice variability changes and is not entirely natural.”
The results are in line with what Arctic scientists would expect, said Julienne Stroeve, a researcher at the National Snow and Ice Data Center in Boulder.