By Chelsea Harvey
22 February 2017
(The Washington Post) – One of Antarctica’s most rapidly melting glaciers has shed yet another large block of ice in an event that NASA scientists say is “further evidence of the ice shelf’s fragility.” The agency drew attention to the incident in a tweet Wednesday morning.
Pine Island Glacier, located on the edge of the increasingly unstable ice sheet of West Antarctica, is a top concern for climate scientists and one of the region’s biggest potential contributors to global sea level rise. It’s pouring about 50 billion tons of ice into the ocean each year, and scientists think this rate could continue to increase in the future. Altogether, the glacier has the potential to raise global sea levels by an estimated two feet.
Scientists’ concern stems largely from the glacier’s interaction with the ocean, which laps against the exposed front of the floating ice shelf and also travels deep beneath it. Warming ocean waters can cause glaciers to melt from the bottom up, making them less stable and more likely to break. In fact, Pine Island Glacier has experienced several significant calving events — that’s when an iceberg breaks off from the ice shelf — in recent years. In 2015, the glacier lost a massive iceberg with an area of more than 200 square miles.
The most recent event, which was captured via satellite imagery at the end of January, is small in comparison — NASA scientists estimate that the area of ice lost only spans a square mile or so. But the event speaks to the fact that the glacier is still melting and breaking.
“I think this event is the calving equivalent of an ‘aftershock’ following the much bigger event,” said Ian Howat, a glaciologist at Ohio State University, in a recent statement. “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.” Indeed, scientists have previously observed multiple small rifts in the ice that they think could lead to more calving events in the future.
The incident comes as the future of the agency’s climate research grows increasingly uncertain. Last November, just after President Trump was elected, one of his campaign advisers shocked the climate science community by suggesting that the new administration should curtail NASA climate research activities.
And now, the issue has cropped up again in a hearing conducted last Thursday by the House Committee on Science, Space and Technology. At the hearing, committee chair Lamar Smith (R-Tex.) reportedly stated that he’d like to see a “rebalancing” at NASA, and later told E&E News that he’d like the agency to focus more on space exploration, while other agencies can focus on earth sciences and climate change. [more]