Y: Scientists are carefully monitoring the west Antarctic ice sheet. It’s melting, and has been responsible for about four percent of the global rise in sea levels to date. They expect it to show further effects from human-caused global climate change in coming decades. And Don, if it all melts, global sea levels will rise by four feet, putting many coastal cities under water. The Thwaites glacier sits like the keystone of an arch at the center of the ice sheet, and extends outward from Antarctic land into the ocean. It is critical because it holds back this much larger ice sheet.
D: I imagine that scientists are very interested in learning about this glacier’s stability.
Y: Yes they are. The Thwaites glacier is deteriorating, and may eventually collapse, but researchers don’t know when. It could be more than a century, but it could be only a few decades.
D: Good grief Yaël! What are scientists doing to learn more?
Y: In 2020 a team of American researchers announced their first measurements of the temperature of the ocean water under the glacier’s grounding zone. This is where the glacier meets the coast as it extends outward over water.
D: They must have bored through lots of ice to get those measurements.
Y: They did. The hole they drilled was a foot wide and two thousand feet deep. They lowered a device designed to measure several parameters of the water under the ice, including its temperature and turbulence.
D: So, what did they find?
Y: The water was two degrees above freezing, which was warmer than expected. This might indicate that the glacier will collapse in a shorter timescale.