Antarctic glacier just lost a chunk the size of Manhattan, as sea ice levels reach record low

“We’re looking at a record minimum in Antarctica.”

CREDIT: NASA Earth Observatory
CREDIT: NASA Earth Observatory

Antarctic sea ice extent appears to have reached a record low, according to initial data from the U.S. National Snow and Ice Data Center (NSIDC).

Sea ice in the region typically reaches its smallest extent at the end of February; this week, it contracted to 2.287 million square kilometers (883,015 square miles), slightly less than the 2.290 million square kilometers (884,173 square miles) recorded in 1997, Reuters reported.

“Unless something funny happens, we’re looking at a record minimum in Antarctica,” NSIDC director Mark Serreze told Reuters. “Some people say it’s already happened… We tend to be conservative by looking at five-day running averages.”

Last month— the third-warmest January on record globally— sea ice extent at both poles was well below average for the month: 8.6 percent below the 1981–2010 average in the Arctic, and 22.8 percent below average in the Antarctic, according to the National Oceanic and Atmospheric Association (NOAA). Both measurements were the smallest January sea ice extent since satellite records began in 1979.

Glaciers didn’t fare much better. An iceberg the size of Manhattan broke off Antarctica’s Pine Island Glacier in January. The same glacier lost a much bigger iceberg — 10 times the size of Manhattan — back in 2015. Simon Gascoin, an ice and remote sensing expert at France’s National Center for Scientific Research, told Climate Central this week that “many studies have shown that Pine Island Glacier is retreating and thinning. That the recent rifting and calving could totally be evidence of an ongoing, rapid disintegration of the ice shelf, mostly due to ocean warming.”

The most dramatic example of the region’s rapid changes is Larsen C, Antarctica’s fourth-largest ice shelf. The crack in the shelf is now over 100 miles long and expanding rapidly — growing 17 miles since December, as the New York Times recently documented. The crack is only about 20 miles from the end of the ice shelf, and researchers told the Times they expect the break to come within a few months, spawning “one of the largest icebergs ever recorded.”

The ripple effect of destabilizing and disintegrating ice shelves and glaciers could be extreme, as Climate Central explained:

The glaciers and ice shelves help hold back a massive ice sheet on land. Their failure would send that ice to the ocean, pushing sea levels up to 13 feet higher than they are today. Some research has indicated that the melt of these glaciers is unstoppable, though their disappearance won’t necessarily happen overnight.

As human-caused climate change continues drives global temperatures up, Arctic sea ice has been rapidly declining. That trend wasn’t so clear in Antarctica, where floating sea ice grew slightly in recent years. That made it a favorite talking point among those who reject or question the scientific consensus on climate change. Scientists have been clear that Antarctic seasonal ice trends are a complex puzzle; NOAA researchers postulated in 2014 that expanding winter sea ice in the region may actually be the result of recent warming, not evidence against it.

“We’ve always thought of the Antarctic as the sleeping elephant starting to stir. Well, maybe it’s starting to stir now,” NSIDC’s Serreze said.