It’s not always gloom and doom around here – Chinese CO2 emissions have stalled, global forest loss has been reversed, and there was even a new species of porcupine discovered in Brazil not long ago! But then, well: gloom, doom.
A new study conducted at NASA finds the last remaining section of Antarctica's Larsen B Ice Shelf, which partially collapsed in 2002, is quickly losing strength and will likely completely disintegrate by 2020.
A research team headed by Ala Khazendar of NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California, found the remains of Larsen B Ice are flowing faster, becoming increasingly fragmented and developing large cracks."These are warning signs that the remnant is disintegrating," Khazendar said. "Although it’s fascinating scientifically to have a front-row seat to watch the ice shelf becoming unstable and breaking up, it’s bad news for our planet. This ice shelf has existed for at least 10,000 years, and soon it will be gone."
Not only is this a concern for the massive ice shelf itself, but these frozen formations act as gatekeepers for glaciers flowing from Antarctica and heading for the sea. Without the ice shelves to impede progress, glacial ice enters the ocean faster and quickens the speed of global sea level rise.
After the 2002 Larsen B collapse, the glaciers behind the failed segment of shelf sped up as much as eight times – the equivalent of a car increasing speed from 55 to 440 mph.
The Larsen B remnant is located in the Antarctic Peninsula, which extends toward the southern tip of South America; it’s formidable in size, measuring about 625 square miles (1,600 square kilometers) in area and about 1,640 feet (500 meters) thick at its thickest point. Khazendar says that his estimate of the remnant's remaining life span was based on the likely scenario that a huge, widening rift that has formed near the ice shelf's grounding line will eventually crack all the way across, notes NASA. The free-floating remnant will shatter into hundreds of icebergs that will drift away, and the glaciers will ramp up for their unhampered march to the sea.
“This study of the Antarctic Peninsula glaciers provides insights about how ice shelves farther south, which hold much more land ice, will react to a warming climate,” said Eric Rignot, co-author of the study and a glaciologist at JPL.
"What is really surprising about Larsen B is how quickly the changes are taking place," Khazendar said. "Change has been relentless."
The study was published online in the journal Earth and Planetary Science Letters.