Antarctica’s Ice Loss Is Speeding Up, with Sharp Acceleration in Past 5 Years

Antarctica’s Ice Loss Is Speeding Up, with Sharp Acceleration in Past 5 Years

SOURCE: Inside Climate News and Nature DATE: June 13, 2018 SNIP: The most complete assessment to date of Antarctica’s ice sheets confirms that the meltdown accelerated sharply in the past five years, and there is no sign of a slowdown. That means sea level is expected to rise at a rate that will catch some coastal communities unprepared despite persistent warnings, according to the international team of scientists publishing a series of related studies this week in the journal Nature. The scientists found that the rate of ice loss over the past five years had tripled compared to the previous two decades, suggesting an additional 6 inches of sea level rise from Antarctica alone by 2100, on top of the 2 feet already projected from all sources, including Greenland. Between 1992, when detailed satellite measurements started, and 2012, Antarctica lost about 76 billion tons of ice per year. But since 2012, that rate has tripled to about 219 billion tons of ice loss per year, the scientists found. Another study, published June 13 in the journal Science Advances, raises even more concerns about the vulnerability of Antarctic ice to global warming. Data from radar and laser readings of the ice enabled scientists with the University of Texas at Austin and the University of Waterloo to map a vast network of channels in the base of many ice sheets formed by intrusions of warm water. Some are several kilometers wide, said University of Texas at Austin researcher Jamin Greenbaum. They found the channels everywhere they looked, including beneath the ice shelf of the Totten Glacier, in East Antarctica, as well...
Unprecedented U.S.-British project launches to study the world’s most dangerous glacier

Unprecedented U.S.-British project launches to study the world’s most dangerous glacier

SOURCE: The Washington Post DATE: April 30, 2018 SNIP: The largest U.S.-British Antarctic mission in seven decades officially launched at an event in Cambridge on Monday, as the two countries pooled dollars and scientific resources for missions to West Antarctica’s Thwaites glacier — a Florida-size ice body that, scientists fear, could flood the world’s coastlines in our lifetimes. “For global sea-level change in the next century, this Thwaites glacier is almost the entire story,” said David Holland, a geoscientist at New York University. Thwaites is wide and deep and flows out of the heart of West Antarctica, a marine ice sheet that could contribute about 10 feet of global sea-level rise. Thwaites is losing ice rapidly, with its 50 billion tons per year currently driving 4 percent of global sea-level rise, and sits perched in 2,600-foot-deep waters atop a seafloor “bump” that scientists fear is the last thing holding it in place. Thwaites is a key part of the reason that recent computer modeling studies have predicted that the Antarctic could double the previously projected rate of sea-level rise during this century. It’s among the most difficult places on Earth for humans to...
Sea levels could be rising faster than predicted due to new source of Antarctic ice melting

Sea levels could be rising faster than predicted due to new source of Antarctic ice melting

SOURCE: The Independent and Science Daily DATE: April 18, 2018 SNIP: Sea level rise could be happening at a faster rate than previously thought, as scientists have identified a new source of melting ice in Antarctica. Melting glaciers can create a positive feedback loop in which the more they melt, the more they drive further melting, according to the Australian team. They predict that the processes they identified could be playing a role in accelerating both sea level rise and climate change. As glaciers melt, they produce fresh water. When this meltwater enters the ocean surrounding the glacier it makes the surface layer less salty and therefore more buoyant. This leads to a layer of water floating on the surface, and prevents the natural mixing of the ocean. The lack of mixing becomes a problem during winter, as it prevents warm water at greater depths from mixing with cooler water above. With a pool of warm water underneath them, the melting of the bottom side of the glaciers...
Sea level fears as more of giant Antarctic glacier floating than thought

Sea level fears as more of giant Antarctic glacier floating than thought

SOURCE: Agence France Presse DATE: March 20, 2018 SNIP: More of a giant France-sized glacier in Antarctica is floating on the ocean than previously thought, scientists said Tuesday, raising fears it could melt faster as the climate warms and have a dramatic impact on rising sea-levels. The Totten Glacier is one of the fastest-flowing and largest glaciers in Antarctica with scientists keen to keep a close eye on how it melts given the enormous amount of water it could potentially unleash. Using artificially created seismic waves that help scientists see through the ice, researchers have discovered that more of the Totten Glacier floats on the ocean than initially thought. The findings are important because recent studies have shown the Totten Glacier’s underbelly is already being eroded by warm, salty sea water flowing hundreds of kilometres inland after passing through underwater “gateways”. As it does, the portion of the glacier resting on water rather than rock increases, accelerating the pace of...
New Maps Highlight Antarctica’s Flowing Ice

New Maps Highlight Antarctica’s Flowing Ice

SOURCE: EOS DATE: March 12, 2018 SNIP: From bold purple to brilliant yellow-orange bursts, the map above pinpoints regions along coastal Antarctica that have recently experienced moderate to severe ice loss. The map’s surface ice velocities, measured in meters per year, come from Landsat 7 and 8 data averaged over 2013–2015. As this map shows, ice loss in western Antarctica is faster and more extensive than in the east, particularly in the Ronne (upper) and Ross (lower) ice shelves. The data underlying this map that depicts recent Antarctic ice flow are from a 13 February study published in The Cryosphere. Not only is ice loss in western Antarctica already much higher than on eastern shores, but it’s also accelerating, according to the research team behind the map and paper. By comparing the most recently available Landsat data with earlier estimates of ice velocity from 2008, the team could determine where ice loss has sped up or remained steady across nearly the entire Antarctic Ice Sheet. [T]he speed of ice loss [in the Marguerite Bay area] increased from about 2,600 to 3,000 meters per year in some locations. That’s a jump of roughly 400 meters per year...