First Results From NASA Satellite Map 16 Years of Melting Ice Sheets

This shows the amount of ice gained or lost by Antarctica between 2003 and 2019. Dark reds and purples show large average rates of ice loss near the coasts, while blues show smaller rates of ice gain in the interior. The circle in the middle is over the South Pole where the instrument does not collect data. (Credit: Benjamin Smith / University of Washington)

(CN) — Perspective can mean the world when observing a melting glacier.

Greenland and Antarctica’s ice sheets are melting at alarming rates due to changes in the climate and oceans. A warming Earth has left the large land masses much thinner than in previous centuries and they are the subject of a study published Thursday in the journal Science.

Researchers were able to measure the amount of ice melt over a 16-year period thanks to a space laser.

The Ice, Cloud and land Elevation Satellite 2 (ICESat-2) shows that the loss of ice from Antarctica and Greenland’s ice sheet raised sea levels by 0.55 inches since 2003. The island nation of Greenland is dominated by a 660,000 square-mile sheet of ice that covers roughly 80% of the landmass and is one of the only permanent ice sheets outside the South Pole.

The researchers found Greenland’s ice sheet lost amounted to 200 gigatons of ice per year and Antarctica lost 118 gigatons of ice per year. A single gigaton amounts to enough ice to fill 400,000 Olympic-sized swimming pools according to the study authors.

The results the researchers saw did not surprise them, said co-author and glaciologist Benjamin Smith with the University of Washington.

“A lot of good research has been done on how the ice sheets are changing, and how that has contributed to sea-level rise, and we’ve known for a while that the ice sheets are losing a lot of mass, and it’s going into the oceans,” Smith said in an interview.

Consider that previous studies have shown if Greenland’s ice sheet were to completely melt away it would account for a 23-foot rise in global sea levels.

Study co-author scientist Tom Neumann said the team were able to look at details of change in individual glaciers and ice shelves at the same time. Co-author and glaciologist Benjamin Smith with the University of Washington says the fringes of the Antarctic continent are becoming thinner, especially in the western region and outweighs any gains in the interior.

“In West Antarctica, we’re seeing a lot of glaciers thinning very rapidly,” Smith said in a statement. “There are ice shelves at the downstream end of those glaciers, floating on water. And those ice shelves are thinning, letting more ice flow out into the ocean as the warmer water erodes the ice.”

Smith names the Kangerdulgssuaq and Jakobshavn glaciers as examples of losing 14 to 20 feet of elevation per year due to warmer summers and warm waters eroding away the ice.

According to the study authors, they were able to measure the melt in floating ice shelves around Antarctica at the same time while measuring the continent’s ice sheet.

Glaciologist and study co-author Helen Fricker with the Scripps Institution of Oceanography at the University of California, San Diego, compares those floating ice shelves to ice cubes in a cup of water.

“It’s like an architectural buttress that holds up a cathedral,” Fricker said. “The ice shelves hold the ice sheet up. If you take away the ice shelves, or even if you thin them, you’re reducing that buttressing force, so the grounded ice can flow faster.”

Smith said the study highlights the relationship between sea-level rise and the variables connected to it and how the thinning of floating ice leads to the thinning of grounded ice — implying that warming ocean water is responsible for some of the mass loss we’re seeing.

The study also helps researchers calibrate computer models of the ice sheets, which can then help make predictions of future sea-level rise.

“The goal is for people who live close to sea level to understand how long they can expect their infrastructure to stay above water, and for people everywhere to understand how their choices about how they live influence climate and sea level,” Smith said.

NASA’s Jet Propulsion Laboratory, University of Buffalo and Colorado School of Mines were also involved in the study.

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