- Antarctic glaciers are melting at unprecedented speed. This rapid ice loss contributes to a rise in sea level.
- In a recent study, scientists found that the Thwaites glacier in western Antarctica is likely to reach an irreversible melting point, after which it will lose all of its ice over a period of 150 years.
- If the entire Thwaites glacier melted, the sea level would rise at least 1.5 feet.
- Some experts warn that the collapse of the Thwaites glacier could trigger a chain reaction of melting that would elevate the sea level by another 8 feet.
- For more information, visit the Business Insider homepage.
In the western Antarctic, a glacier the size of Florida loses ice faster than ever.
Sections of the Thwaites glacier retreat up to 250 meters annually and contribute to 4% of the world's sea-level rise. This loss of ice is part of a broader trend: the entire Antarctic ice sheet melts almost six times faster than it did 40 years ago. In the 1
Authors of a new study now report that the speed at which five Antarctic glaciers slip off the ice has doubled in the past six years. This turns the Thwaites Glacier into a melt bomb.
The scientists reported in the journal Proceedings of the National Academy of Sciences that the glacier poses the greatest risk to future sea-level rise, probably marching toward an irreversible melting point.
"After reaching the turning point, the Thwaites glacier could lose all of its ice in 150 years," said study author and NASA scientist Hélène Seroussi in a press release. "That would mean a sea-level rise of about half a meter."
Another study author, Alex Robel, added that nothing could stop the melting of the ice if the glacier crossed the Rubicon – even if the temperature on Earth would not rise any more.
"It will go on by itself and that is the concern," he said.
Why the Thwaites Glacier could reach a turning point
The Thwaites Glacier is a large mass of ice formed from snow that has been compressed over time. It is part of the Antarctic ice sheet – a large continental glacier that covers at least 32,000 km² of land (roughly the area of the United States and Mexico together).
The Antarctic is surrounded by a verge of ice sheets and floating ice shelves that form a physical barrier between the ocean and the inland ice on the continent. As Ross Virginia, director of the Institute of Arctic Studies at Dartmouth College, told Business Insider, these floating leaves are "like a dam". The barrier prevents continental ice from flowing into the ocean, where it melts and raises global sea levels.
With rising sea temperatures, warmer water at the base of these ice sheets causes them to melt from below. Melting is the result of melting: In February, an almost Manhattan-sized gap was discovered under the Thwaites Glacier. This cavity was large enough to hold 14 billion tons of ice.
Read More: Below Antarctica is a cavity two-thirds the size of Manhattan-a sign that ice sheets melt faster than thought.
Every year, the part of the floating ice shelf of the Thwaites Glacier melts. The water that extends into the sea becomes bigger when the seawater erodes its base. Scientists such as Seroussi and Robel are following the Thwaites grounding line: the place where the continental ice lifts off the ground and begins to float on the water. (Imagine a promontory that extends into the air over a cliff edge – the same concept applies to glaciers, except that the ice is over water instead of air.)
This line of grounding was almost moving between 1992 and 2011 14 km according to a 2014 study; The further the stain moves inland, the more likely it is that the glacier melts.
What a melting Thwaites glacier means to the sea level.
Together with the Greenland ice sheet, the Antarctic ice sheet contains more than 99% of the world's fresh water.
Most of the water is frozen in masses of ice and snow, which can be up to 10,000 feet thick. However, as human activities release more greenhouse gases into the atmosphere, the oceans absorb 93% of the excess heat that these gases store. The warm air and warm water cause ice sheets and glaciers to melt at unprecedented speed.
Seroussi said that the Thwaites could reach their turning point in the next 200 to 600 years, after which they could lose all their ice. If the entire Thwaites glacier were to melt away, this would lead to a 1.64-foot increase in sea level worldwide, according to the latest study (although another study estimated the increase to be almost 2 feet).
But Thwaites prevents its neighbor glaciers from flowing into the ocean. Some other scientists believe that the collapse of the entire Thwaites glacier could also destabilize the surrounding glaciers on the Antarctic ice sheet.
If you go, they could all go – and this chain reaction would raise the sea level an additional 8 feet.