Since the beginning of satellite observations, the sea-ice extent in the Arctic was found to be the fourth-lowest this year, NASA noted on Tuesday. The ice cap floating on the Arctic ocean shrinks and expands with the seasons, reaching a maximum in March and a minimum in September.
Thinning is accelerating
A joint analysis by the U.S. space agency and the National Snow and ICE Data Center (NSICD) in Boulder, Colorado found that the Arctic sea ice hit its annual minimum on September 11, when it retreated to 1.70 million square miles. This was lower than the average minimum for all years between 1981 and 2010 by 699,000 square miles (1.81 million square km).
A record minimum was hit by the Arctic sea in 2012, when just 1.32 million square miles i.e. 3.41 million square km of the area, was covered by ice. NASA says an August storm was partially responsible for the low amount of ice.
Climate changes have led to a decline in the Arctic sea ice since the 1970s, and thinning is accelerating, according to a recent research. In March, a study published in the journal The Cyrosphere noted that the September sea ice thinned by 85% between 1975 and 2012 (from 9.8 feet to 1.4 feet). The thinning of ice means less of ice cover and more open ocean as the ice packs are eaten away by the melt.
Arctic ice less resilient
Walt Meier, a sea-ice scientist at NASA’s Goddard Space Flight Center, noted: “This year is the fourth lowest, and yet we haven’t seen any major weather event or persistent weather pattern in the Arctic this summer that helped push the extent lower as often happens.” Some areas were warmer than the last year, but other places were cooler, Meier said.
Meier noted that sea ice is becoming less and less resilient, adding that the ice pack was not fragmented by unusual weather this year. The expert further said that there was a time when the sea-ice cap used to be a solid sheet, but now it has fragmented into smaller floes that are more exposed to warm waters of the Ocean. Earlier, the warm waters could only hit the sides of the huge chunk of ice, but now, the warm waters enter from underneath, leading to the melting of ice packs from within.
Since the extreme low in 2012, scientists no longer get excited with a slight bump in the sea-ice minimums as the numbers still remain at low levels and suggest an ongoing downward trend.