Bhubaneswar: While the Arctic sea ice cover has been witnessing decades-long pattern of shrinking and thinning, it retreated to near-historic lows in the Northern Hemisphere this summer. According to researchers at NASA and the National Snow and Ice Data Center (NSIDC), Arctic sea ice melted to its minimum extent for the year on Sept.11, 2024, marking another year of significant ice loss in the Northern Hemisphere.

This year, the Arctic sea ice shrank to a minimal extent of 1.65 million square miles is approximately 1.94 million square kilometers below the 1981-2010 end-of-summer average, covering an area larger than Alaska.

Tracking changes in sea ice has revealed a wide range of impacts including loss of habitat to polar wildlife to local communities being affected in Arctic and international trade routes.

Over the past 46 years, satellites have observed persistent trends of more melting in the summer and less ice formation in winter.

Though amount of frozen seawater in the Arctic fluctuates during the year, it has been seeing a downward since the start of the satellite record for ice in the late 1970s. Since then, the loss of sea ice has been about 30,000 square miles (77,800 square kilometers) per year, according to NSIDC.

As of now, scientists use data from passive microwave sensors aboard satellites in the Defense Meteorological Satellite Program along with additional inputs rom the Nimbus-7 satellite, jointly operated by NASA and the National Oceanic and Atmospheric Administration (NOAA) to measure sea ice extent.

Ice thickness measurements collected with spaceborne altimeters, including NASA's ICESat and ICESat-2 satellites, have found that much of the oldest, thickest ice has already been lost.

Commenting on the changing patterns, Nathan Kurtz, lab chief of NASA's Cryospheric Sciences Laboratory at the agency's Goddard Space Flight Center in Greenbelt, Maryland said Sea ice is not only shrinking, it's getting younger.

"Today, the overwhelming majority of ice in the Arctic Ocean is thinner, first-year ice, which is less able to survive the warmer months. There is far, far less ice that is three years or older now," Kurtz added. 

Overall, the loss of sea ice increases heat in the Arctic, where temperatures have risen about four times the global average, he further said. 

[Disclaimer: This story is a part of ‘Punascha Pruthibi – One Earth. Unite for It’, an awareness campaign by Sambad Digital.]