Antarctica’s “Doomsday” Glacier: Its Collapse Could Trigger Global Floods and Swallow Islands

The massive Thwaites glacier in West Antarctica contains enough ice to raise
global sea levels by 65cm if it were to completely collapse. And, worryingly,
recent research suggests that its long-term stability is doubtful as the
glacier hemorrhages more and more ice.

Adding 65cm to global sea levels would be coastline-changing amounts. For
context, there’s been around 20cm of sea-level rise since 1900, an amount that
is already forcing coastal communities out of their homes and exacerbating
environmental problems such as flooding, saltwater contamination and habitat
loss.

But the worry is that Thwaites, sometimes called the “doomsday glacier”
because of its keystone role in the region, might not be the only glacier to
go. Were it to empty into the ocean, it could trigger a regional chain
reaction and drag other nearby glaciers in with it, which would mean several
meters of sea-level rise. That’s because the glaciers in West Antarctica are
thought to be vulnerable to a mechanism called Marine Ice Cliff Instability or
MICI, where retreating ice exposes increasingly tall, unstable ice cliffs that
collapse into the ocean.

A sea level rise of several metres would inundate many of the world’s major
cities – including Shanghai, New York, Miami, Tokyo, and Mumbai. It would also
cover huge swathes of land in coastal regions and largely swallow up low-lying
island nations like Kiribati, Tuvalu, and the Maldives.

As big as Britain

Thwaites is a frozen river of ice approximately the size of Great Britain. It
already contributes around 4% of the global sea-level rise. Since 2000, the
glacier has had a net loss of more than 1000 billion tons of ice and this has
increased steadily over the last three decades. The speed of its flow has
doubled in 30 years, meaning twice as much ice is being spewed into the ocean
as in the 1990s.

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