Satellites Show 12.5 Trillion Tons of Polar Ice Melted Since 1979, Raising Seas 1 Inch
Updated
Updated · NBC News · Sep 16
Satellites Show 12.5 Trillion Tons of Polar Ice Melted Since 1979, Raising Seas 1 Inch
3 articles · Updated · NBC News · Sep 16
Summary
A new international satellite analysis found Greenland and Antarctica lost 12.5 trillion tons of ice since 1979, adding about 1 inch to global sea levels.
Five-sixths of that loss came from warmer ocean water eroding ice sheets from below and the sides, with glacier discharge accelerating sharply after the 1990s and surging in the 2010s.
The study linked each third of an inch of sea-level rise to 2 million to 3 million more people facing annual flooding, while Greenland’s Jakobshavn glacier is retreating by as much as 50 meters a day.
Using 45 surveys and 27 satellites, researchers said a 2020-2023 slowdown reflected short-term weather— including heavy East Antarctic snowfall— and newer measurements show the longer-term acceleration has resumed.
Outside scientists said the dominance of dynamic ice loss raises concern about instability and possible tipping points, suggesting sea-level risks will keep building for decades even if warming stops.
Could the temporary slowdown in ice loss from 2020 to 2023 be masking a much more dangerous, irreversible climate tipping point?
If warmer oceans are eroding ice sheets from below, is a catastrophic runaway collapse already unstoppable regardless of future climate action?
With millions facing flood risks from minor sea-level rise, which coastal megacities will be the first to become entirely uninhabitable?
Polar Ice Loss and the 31.4 mm Sea Level Rise: Causes, Cascading Climate Risks, and the Human Toll to 2026
Overview
Polar ice sheets in Greenland and Antarctica have lost over 11,000 billion tonnes of ice since 1979, causing global sea levels to rise by more than 31 millimetres. This rapid loss is mainly driven by warming ocean waters, which accelerate glacier discharge and send massive amounts of cold, fresh meltwater into the North Atlantic. As a result, ocean salinity drops, threatening to slow or even collapse the Atlantic Meridional Overturning Circulation (AMOC), a key global current. These changes trigger feedback loops—such as lower ice elevation and darker surfaces absorbing more heat—that further speed up melting, amplify global warming, and put millions of coastal residents at risk worldwide.