“Imagine spraying warm salted water on an icy road. It doesn’t take metres of salt water to melt the ice quickly.” Eric Lynott
Thwaites Glacier is a large ice cap the size of Florida in the highly vulnerable West Antarctic Ice Sheet, currently accounting for 4% of global sea level rise. Although the glacier has only been studied since 2018, satellite and radar data have provided valuable information that is crucial to understanding the potential sea level rise that is of concern for coastlines around the world.
The meltwater Warm ocean currents have destructive effects on the Antarctic Circumpolar Currentis a key part of Earth’s circulation. The exchange of heat and carbon dioxide between the Southern Ocean and the atmosphere is essential for the stability of the Antarctic ice sheet. Paleoclimate data shows that ocean currents slow down during glacial periods and speed up during interglacial periods. This means that in the future, the Southern Ocean will store less carbon dioxide and bring more heat to Antarctica. This active process could cause ocean currents to slow down by 40 percent within 30 years, which is a dire threat to the stability of the Earth’s climate.
As far as we know, all of the damage to this widely studied glacier has occurred below sea level. Wind-driven warm water erodes the bottom edge of the ice, creating cavities that allow the ice to expand further and produce vertical cracks up to the ice surface. (See the inset image below from Christopher Cartwright for an example.) Warm water damage to the bottom edge of the ice from the bottom was assumed to end at the ice line, where the ocean meets bedrock. This is no longer the case. Recent radar data shows that warm water (mid-30°F) is now intruding daily with the tides, reaching several miles inland.
Anupama Chandrasekaran writes for EOS.
Most ice sheet simulations do not accurately predict the recent retreat of the Thwaites Glacier because they assume the glacier’s ice line is fixed. Recent research on Thwaites and Other Glaciers The boundary between floating ice and ice attached to the seafloor has been shown to change with the daily tides.
Cut into small pieces
Using satellite radar data from private companies Ice Eye Using data collected over three months in 2023, a team of glaciologists watched the glacier’s surface rise and fall throughout the day to create a detailed picture of the changing ice line of Thwaites Glacier.
“What’s different about this study is that they took multiple measurements over the course of a day,” he said. Alex Brisbone“What they could see was [were] These are really short-term processes.”
Satellites can only see the surface of the ice, but because the ice is compressed, even slight vertical movements signal that the glacier bed is also rising, they write. Eric Rignot via email. Rignot, a glaciologist at the University of California, Irvine and NASA’s Jet Propulsion Laboratory, is the study’s first author.
The team found that the ice rose and fell with the tides, and their data showed that during average high tides, ice on the ice sheet moved up to 6 kilometers (3.7 miles) inland.
When tides were particularly high, the glacial uplift suggests that a thin layer of seawater of up to 10 centimetres (4 inches) was pushed a further 6 kilometres (3.7 miles) inland. The researchers think this extra water could be causing more glacial melting than currently estimated, as it replaces the cold meltwater that covers the base of the glaciers with warmer, saltier seawater.
