Leading scientists have warned that nine of the tipping points identified over a decade ago are now active. One of those tipping points is the West Antarctic Ice Sheet (WAIS). Thwaites glacier, also known as the doomsday glacier, has been alarming scientists about a looming collapse that could raise sea levels rapidly.
International scientists have been intensively studying this particular glacier for over a decade. When Thwaites glacier collapses, it will likely take the rest of West Antarctica’s glaciers with it.
West Antarctica has glaciers that extend for miles into the ocean. These marine extensions provide the plug that keeps the Inland Ice from flowing into the sea. In the case of Thwaites, the glacier flow has doubled in just the past three decades. The fast flow of ice into the ocean is rising sea levels, and inland snowfall is not replacing the ice that’s lost to the sea, according to scientists. They emphasize that this situation will only get worse.
The land ice of Thwaites has the potential to raise sea levels two feet, and if West Antarctica goes down with it, eleven feet of sea-level rise will occur.
In the past ten years, the tongue has continued to fracture and separate from the Thwaites Eastern Ice Shelf. By the time the 2019 image was acquired, the main tongue had retreated substantially, and the ocean in front of Thwaites had become filled with mélange, a mixture of icebergs and sea ice.
Unlike Pine Island Glacier—which tends to shed large icebergs every few years (now almost annually)—the icebergs that now break from Thwaites are generally not large enough to be named and tracked by the U.S. National Ice Center. Instead, the glacier is constantly producing many small broken bits.
The melting of floating ice as it makes contact with the ocean is a key reason why the glacier is coming unglued. Seawater that is a few degrees above freezing is melting the ice shelf from below. Warm water has recently been recorded near the Thwaites Glacier grounding line—the location where the glacial ice rests on the seafloor.
“What the satellites are showing us is a glacier coming apart at the seams,” said Ted Scambos, a senior scientist at the University of Colorado. “Every few years a new area seems to be letting go and accelerating. Like taffy being stretched out, this glacier is being drawn into the ocean.”
We rappelled into the bergschrund of Thwaites Glacier to see if bedrock was exposed there so we could sample it and determine the last time it was exposed to sunlight (i.e. glacier retreat). Unfortunately, no luck, but VERY cool caves @GlacierThwaites! pic.twitter.com/4uQ2JhLMk1
— Seth Campbell (@Alpinesciences) January 31, 2020
A 2nd cave attached to the 1st on @GlacierThwaites!
It took several days of methodical roped GPR surveying & cutting into the crevasse roof to reach these caves in hopes of finding bedrock. We collected rock samples in a similar crevasse at Ohio Range in 2013. No luck this time! pic.twitter.com/v3eIsyVatk
— Seth Campbell (@Alpinesciences) January 31, 2020
Scientists have found that a significant portion of the Thwaites’s grounding line is now gone. The loss will be catastrophic for low lying coastal areas from Miami to Shanghai. Antarctica’s contribution to sea level is rising, but has not approached the catastrophe unfolding in Greenland.
Laura Geggel of Live Science writes that warm water and turbulence is clawing at the underbelly of the glacier and thinning it quickly:
An underwater robot named Icefin that has gone where no submersible has gone before — to the underbelly of Antarctica’s “Doomsday Glacier” — has uncovered unusually warm temperatures there.
The hunk of ice, officially known as the Thwaites Glacier, earned its ominous nickname because it is one of Antarctica’s fastest melting glaciers. Even so, scientists were surprised to learn that waters at the ground line, the region where the glacier meets the sea, are more than 3.6 degrees Fahrenheit (2 degrees Celsius) above the normal freezing temperature, according to news reports.
Like many of its neighbours in West Antarctica, #ThwaitesGlacier has an Achilles heel. And that's the inclination of the seabed underneath the glacier which promotes further melting and mass loss as warm water increasingly impinges the underside of its floating front. pic.twitter.com/ni4AetBZ6c
— Jonathan Amos (@BBCAmos) January 28, 2020
Scientists believe that it is changing wind patterns that are causing the problem of warm water and turbulence pushed under the marine extensions of WAIS glaciers. “…middepth warm water, called circumpolar deepwater, up from the deep ocean and onto the continental shelf in front of Antarctica and toward Thwaites”.
Just worked out how to get a higher res version – hope this helps! pic.twitter.com/Cn45lspvdQ
— Joanne Johnson (@geologicalJo) February 6, 2020
— Stef Lhermitte (@StefLhermitte) March 6, 2019
4 years of @ThwaitesGlacier ice tongue from @CopernicusEU #sentinel1 satellite imagery showing how this chaotic ice tongue has become a collection of icebergs glued together by sea ice. pic.twitter.com/0QgeXed8yg
— Stef Lhermitte (@StefLhermitte) March 2, 2019