Satellite Images Reveal Greenland and Antarctica Have Lost More Than 12 Trillion Tons of Ice Over the Past 50 Years

Greenland and Antarctica have lost a shocking amount of ice over the past 50 years—and the main culprit might surprise you. Since the 1970s, more than 12 trillion U.S. tons of ice have disappeared from the two landmasses. It’s mostly because glaciers have been flowing faster into the ocean, rather than surface melting, researchers report in the journal Scientific Data on September 16.

They also found that the ice loss has raised global sea levels by more than one inch in that timeframe and has accelerated in recent decades. Otosaka and colleagues put together this comprehensive look at ice loss by compiling 42 independent satellite surveys, gathered during 27 satellite missions, dating back to 1972 for Greenland and 1979 for Antarctica. With data extending to 2023, the new study represents the longest satellite record ever assembled.

Analyzing the ice dynamics over that period revealed that the frigid regions had collectively lost about 12.5 trillion tons of frozen water. While ice sheets gain mass by accumulating snow, they can lose it through two mechanisms, reports Gizmodo’s Ellyn Lapointe. Atmospheric temperatures drive surface melting, and ocean temperatures drive glacier outflow.

The team found that around 84 percent of Greenland and Antarctica’s ice loss was due to glaciers speeding up their descent into surrounding water, with the remainder due to surface melting. The main culprit of the frozen water’s disappearance was “surprising,” Otosaka tells New Scientist’s Alec Luhn. She expected to see something closer to a 50-50 split.

What’s more, ice loss has more than quadrupled in both locations over the past few decades, the team found. Data from the first couple of analyzed decades showed stable ice sheets. In the 1980s, for instance, Greenland’s ice was vanishing at roughly 66 billion tons per year.

However, that rate jumped to 291 billion tons in the 2010s, a decade when the landmass experienced several extreme summer melt events. Similarly, Antarctica went from losing around 53 billion tons per year in the 1980s to 223 billion tons per year in the 2010s. That’s because many previous estimates relied on oversimplified models of Earth, which didn’t account for factors like winds, ocean currents, tides, and seawater temperature and salinity, which can affect sea level.