Two of the frozen continent’s fastest-moving glaciers are shedding an increasing amount of ice into the Amundsen Sea each year.
The Pine Island and Thwaites glaciers are among the most critical in the world. They are currently holding back ice that, if melted, would raise the world’s oceans by nearly four feet over centuries, an amount that would put many coastal cities underwater.
Glaciers are essentially long rivers of ice. Just as a river collects water that drains from a specific area, Antarctica’s glaciers collect ice from parts of the great ice sheets that cover the continent. The amount of ice that could flow into the Pine Island glacier and then into the sea would eventually raise the world’s sea level by over a foot and a half.
The animation above shows Pine Island glacier flowing into the Amundsen Sea from 2014 to 2017. Twice in that period, the glacier released an iceberg larger than 100 square miles.
The Pine Island’s flow is accelerating rapidly. Its ice shelf, an expanse of ice that floats on water where the glacier meets the sea, has increased its speed by 75 percent from 1973 to 2010.
“This is a result of the warmer waters in front of them,” said Eric Rignot, a climate scientist at the University of California, Irvine, who has done extensive research on polar ice.
“In some relatively colder years, we know the melt rate slowed down and the glaciers slowed down. On warm ocean years, the glacier moves really fast.”