Thwaites Glacier in Antarctica is melting quickly along its base with cracks and crevasses visible, according to a new video. It shows that the glacier is shrinking from below in a way that scientists had not anticipated, as per two studies that were published in the journal Nature on Wednesday. The glacier, which is the size of Britain, is also known as "Doomsday Glacier" since its collapse could drive catastrophic sea level rise.
Watch the video below:
In order to examine the Thwaites Glacier from below, the researchers from the UK-US International Thwaites Glacier Collaboration said that they were able to measure its bottom by installing cameras and probing through a borehole. While the rate of melting beneath much of the ice shelf is slower than previously believed, deep cracks and "staircase" forms in the ice are melting significantly faster. This means there is still a rapid glacier retreat despite small amounts of melting.
"Doomsday Glacier" has been susceptible to climate change over the past 30 years and is responsible for four per cent of the rise in sea level worldwide. According to geologists, if the glacier melts, the world's sea level might rise by 25 inches in the coming years.
In late 2019, a hot water drill was used by the British Antarctic Survey to dig a 600-meter-deep borehole two kilometres from the grounding line. These readings were contrasted with melt rate data collected at five additional sites below the ice shelf. The ocean around the grounding line, where the ice meets the ocean, warmed and salted over a nine-month period, yet the ice base only melted an average of two to five metres each year, less than what had been predicted.
"Our results are a surprise but the glacier is still in trouble. If an ice shelf and a glacier is in balance, the ice coming off the continent will match the amount of ice being lost through melting and iceberg calving. What we have found is that despite small amounts of melting there is still rapid glacier retreat, so it seems that it doesn't take a lot to push the glacier out of balance," said Dr Peter Davis, Oceanographer at British Antarctic Survey and lead author on one of the studies, in a press release.
According to the British Antarctic Survey, a robot named Icefin was lowered through a 600-meter-deep borehole by Dr Britney Schmidt of Cornell University along with a group of scientists. According to researchers, the discoveries made by Icefin provided more detail to the picture of how melting differs beneath the ice shelf. They discovered that the terraces, also known as the stairs, and the crevasses in the ice base are melting quickly.
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Although vertical melting along the ice shelf's base was lower than expected, melting along sloped ice in these cracks is much higher and may be a significant factor in ice loss across Thwaites Glacier and may become the primary trigger for ice shelf collapse.
Dr Britney Schmidt stated in the press release, "These new ways of observing the glacier allow us to understand that it's not just how much melting is happening, but how and where it is happening that matters in these very warm parts of Antarctica. Warm water is getting into the cracks, helping wear down the glacier at its weakest points."
