“What we’ve seen over the years is that the older ice is disappearing,” said Walt Meier, a sea ice researcher at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “This older, thicker ice is like the bulwark of sea ice: a warm summer will melt all the young, thin ice away but it can’t completely get rid of the older ice. But this older ice is becoming weaker because there’s less of it and the remaining old ice is more broken up and thinner, so that bulwark is not as good as it used to be.”
“Unlike in the 1980s, it’s not so much as ice being flushed out –though that’s still going on too,” Meier said. “What’s happening now more is that the old ice is melting within the Arctic Ocean during the summertime. One of the reasons is that the multiyear ice used to be a pretty consolidated ice pack and now we’re seeing relatively smaller chunks of old ice interspersed with younger ice. These isolated floes of thicker ice are much easier to melt.”
Arctic sea ice has not only been shrinking in surface area in recent years, but it’s also becoming younger and thinner as well. In this animation, where the ice cover almost looks gelatinous as it pulses through the seasons, cryospheric scientist Dr Walt Meier of NASA Goddard Space Flight Center describes how the sea ice has undergone fundamental changes during the era of satellite measurements.
Credits: NASA’s Goddard Space Flight Center/Jefferson Beck, producer
“We’ve lost most of the older ice: In the 1980s, multiyear ice made up 20 percent of the sea ice cover. Now it’s only about 3 percent,” Meier said. “The older ice was like the insurance policy of the Arctic sea ice pack: as we lose it, the likelihood for a largely ice-free summer in the Arctic increases.”
Source: NASA’s Earth Science News Team