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Antarctica and Greenland have lost thousands of gigatons of ice in the last 16 years alone. According to new NASA data, that melting ice has contributed to more than half an inch of Rising sea levels worldwide.
Collectively, Antarctica and Greenland have lost more than 5,000 gigatons of ice in the past decade and a half, more than enough to fill Lake Michigan. A gigaton is the equivalent of a billion metric tons, which could fill 400,000 Olympic swimming pools alone, NASA said in a press release.
According to an article published Thursday in the journal Science, the two regions have been collectively responsible for .55 inches of the sea level Rise between 2003 and 2019: about a third of the total global sea level rise during that time.
Data comes from NASA’s Ice, Cloud, and Ground Elevation Satellite 2 (ICESat-2). Launched in 2018, it is the “most advanced Earth observation laser instrument NASA has ever flown in space,” combined with data from its predecessor, ICESat, which collected data from 2003 to 2009.
NASA ICESat and ICESat-2
“If you look at a glacier or ice sheet for a month or a year, you won’t learn much about what the weather is doing to it,” said Ben Smith, a glaciologist at the University of Washington and lead author of the paper. “We now have a 16 year gap between ICESat and ICESat-2 and we can be much more confident that the changes we are seeing on the ice have to do with long-term changes in the climate.”
According to the data, per year, GreenlandThe ice sheet lost an average of 200 gigatons of ice, and AntarcticaHe lost an average of 118.
Using information from both missions, the researchers found not only the amount of melted ice but one of the main Causes. Ice shelves around Antarctica act as barriers to slow down the rate of ice loss (they do not contribute to sea level rise because they are already floating), but as those barriers melt away in warming oceans, it increases the rate of ice loss.
“It’s like an architectural buttress holding up a cathedral,” said Helen Amanda Fricker, co-author and glaciologist at the Scripps Institute for Oceanography at the University of California, San Diego. “Ice shelves support the ice cap. If you remove the ice shelves, or even thin them, you’re reducing that reinforcing force, so the ice on land can flow faster.”
While a large amount of Antarctic ice loss came from floating ice platforms, through the delivery and melting of the iceberg warm water, most of Greenland’s losses were due to surface melt and runoff. In Greenland, coastal glaciers have shrunk dramatically, mainly due to warmer summer temperatures.
NASA ICESat and ICESat-2
The new NASA data is consistent with previous studies of rising sea levels, but satellite lasers provide researchers with a much more detailed analysis of how polar ice is changing over time. While East Antarctica has seen a small increase in its amount of ice, that improvement has been outweighed by huge losses in West antarctica, where the ocean has rapidly warmed up.
“The increase in a single year is not in itself worrisome,” Alex Gardner, co-author and glaciologist at NASA’s Jet Propulsion Laboratory, told CBS News on Friday. “The worrying thing is that this will continue every year for the foreseeable future, adding to a significant rise in sea level over the next 80 years. By 2100 we expect a rise of 2.3, or perhaps 4 feet, of sea level.
Sea level rise is expected to affect millions of people living in coastal cities around the world.
“This is important because civilization has evolved around coastal cities where considerable infrastructure is located near current sea level,” Gardner continued. “When there is a high tide event or a passing storm, they can cause considerable property damage. This damage will greatly amplify as sea level continues to rise and will require municipalities and counties to make difficult decisions about what infrastructure to invest to try and save and what infrastructure should be abandoned. “
