This year has brought some really troubling signs of the global shift in climate. We’ve hit all-time highs for atmospheric carbon dioxide; the Arctic circle is 36 degrees warmer than it should be, and that’s, unfortunately, just the beginning. This week, scientists at the Ohio State University discovered a tremendous crack in some West Antarctic glaciers, and as you might have suspected — that’s really bad news.
The researchers wanted to know what caused a 225 square-mile piece of the Pine Island Glacier to slide off into the ocean. Such break-offs, called “calving events,” generally happen every few years. And generally, they’re not too concerning. But last year’s collapse didn’t start from the usual shifting of glaciers and ice sheets, but from a massive chasm much further up.
That’s a primary concern because the Pine Island Glacier, along with a few others are massive slabs of ice that have, until now, been holding back the West Antarctic Ice Sheet (WAIS). As these glaciers start breaking off, though, it could trigger the collapse of the entire sheet which 6.1 million cubic miles (yes, that’s cubic MILES) of ice. That’s enough to cover all of the United States in a little less than 2 miles of water. And if you’re thinking that sounds like bad news… you’re absolutely right. The WAIS contains enough water to increase global sea levels by up to 3 meters.
Speaking to Gizmodo, lead study author Ian Howat said that the loss of such a huge chunk of the Pine Island Glacier last year was troubling not because it happened, 225 square miles isn’t all that much in the grand scheme of things, but how it happened.
“I think what we’re seeing is the surface expression of a much bigger valley at the base of the ice shelf,” Howat said. “This tells us the ice shelf has weaknesses that are being exploited by increased ocean temperatures.”
The Pine Island Glacier started developing cracks 20 miles inland, these cracks started at the base of the glacier and spread upwards. That means that there are significant increases in temperatures in the water beneath and around Antarctica. As Howat explains, that could make these events much more common over the next couple of years.
“If the ice sheet was going to retreat very slowly on long timescales, we’d just expect to see the usual calving,” Howat said. “This event gives us a new mechanism for ice sheets falling apart quickly. It fits into that picture of a rapid retreat.”