NASA spots iceberg the size of Manhattan breaking off into the ocean
The shape of Antarctica’s Pine Island Glacier is changing rapidly, and concerns have been raised further by footage from NASA satellites showing a 1-mile-long chunk of ice breaking away.
One of the biggest glaciers within the West Antarctic Ice Sheet, the Pine Island Glacier makes up around 20 percent of ice flow to the ocean from the ice sheet. In 2013, an iceberg measuring around 278 square miles, larger than the city of Chicago, was observed to have broken off. The last major break of this nature, which are known as calving, was in 2015 when a section only slightly smaller than the one seen two years earlier broke loose.
Researchers from the Naval Postgraduate School used sensors through 1,640 feet of solid ice to determine how quickly warm water was melting Antarctica’s Pine Island Glacier from beneath.
Credit: Tim Stanton/NPS
The recent event, observed by NASA’s Landsat 8 satellite between January 25 and 29, was ten times smaller than the 2015 incident. However, it is a reminder of Pine Island Glacier’s fragility. Other rifts have been seen developing, including one 6 miles from the ice front that was spotted by one of NASA’s Operation IceBridge flights in late 2016.
“I think this event is the calving equivalent of an ‘aftershock’ following the much bigger event,” said Ian Howat, a glaciologist at The Ohio State University. “Apparently, there are weaknesses in the ice shelf — just inland of the rift that caused the 2015 calving — that are resulting in these smaller breaks.”
Breaking from the inside
Warming oceans and climate change are implicated in the break up of the world’s ice, and glaciers in the West Antarctic are being affected by warm water flowing beneath them. Live Science pointed to a previous study which found that the warming ocean was melting an ice crevasse of the Pine Island Glacier at the bedrock level, causing the glacier to melt from its center.
The Antarctic ice shelf is breaking from in the inside out, and experts fear the West Antarctic Ice Sheet could collapse within a century.
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Image credit: NASA Earth Observatory image by Jesse Allen, using Landsat data from the U.S. Geological Survey and MODIS data from the Level 1 and Atmospheres Active Distribution System (LAADS)
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