Arctic sea ice reached its annual maximum extent on March 17, and joined 2015, 2016 and 2017 as the four lowest maximum extents on record, according to scientists at the NASA-supported National Snow and Ice Data Center (NSIDC) and NASA. In the video, Dr. Claire Parkinson explains how and why NASA studies Arctic sea ice.
The 2018 extent reached 5.59 million square miles, only about 23,000 square miles larger than the lowest maximum on record, in 2017.
Every year, the sea ice cover blanketing the Arctic Ocean and surrounding seas thickens and expands during the fall and winter, reaching its maximum yearly extent sometime between late February and early April. The ice then thins and shrinks during the spring and summer until it reaches its annual minimum extent in September. Arctic sea ice has been declining both during the growing and melting seasons in recent decades.
Claire Parkinson, senior climate scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, explains:
The Arctic sea ice cover continues to be in a decreasing trend and this is connected to the ongoing warming of the Arctic. It’s a two-way street: the warming means less ice is going to form and more ice is going to melt, but also, because there’s less ice, less of the sun’s incident solar radiation is reflected off, and this contributes to the warming.
