The collapse of glaciers along West Antarctica’s Amundsen Sea would raise seas by 1.2 metres.
Several of Antarctica’s most vulnerable glaciers have already begun a runaway meltdown, two new studies suggest. The work provides some of the first detailed forecasts on how quickly glaciers are likely to disappear from a region that has long concerned scientists.
One modeling paper finds that ongoing losses at the Thwaites Glacier have permanently destabilized that ice river, which drains into West Antarctica’s Amundsen Sea. The second study uses satellite radar observations to reveal that Thwaites and five neighbouring glaciers have nothing to hold them back from catastrophic collapse, leaving them more vulnerable than previously thought.
Were they all to melt, the six Amundsen Sea glaciers studied by Eric Rignot’s team contain enough water to raise global sea level by 1.2 metres. That process is likely to unfold slowly: at Thwaites alone, melting over the next century will probably cause sea levels to rise less than a quarter of a millimeter per year, or just 2.5 centimeters in total.
But that rate could speed up dramatically, to more than a millimeter per year, within two to nine centuries, says Ian Joughin, a glaciologist at the University of Washington in Seattle. “We are seeing the early stages of the collapse,” he says…
Thwaites is important because it flows from a broad, deep interior basin into the sea. Its vast storehouse of ice is big enough to contribute significantly to global sea level rise. The nearby Pine Island Glacier is retreating more quickly than Thwaites but drains only a very narrow trough.
The Joughin study “is a seminal paper,” says Andrew Shepherd, a cryosphere expert at the University of Leeds, UK. “It’s the first to really demonstrate what people have suspected, that Thwaites Glacier is a bigger threat to future sea level than Pine Island.”
Global sea levels are currently rising about 3 millimeters a year. Most of that comes from the thermal expansion of the warming oceans; some also comes from melting ice in Greenland and Antarctica.
“These systems, whether Greenland or Antarctica, are changing on faster time scales than we expected. We are kind of rediscovering that every day,” says Rignot.
It is the nature of scientific research to be conservative. Some may think discussions of events comprised of centuries instead of millennia still to be an exaggerated focus. Why talk about it if you ain’t about to live long enough to see it? That only demonstrates an absence of understanding of science and scientific goals. Everything in science tends to flow from the work that preceded whatever is current.
One important decision that needs to be made is allocation of funds and effort between the northern and southern hemispheres. The former tends to get the most attention because where the bulk of our species live. Sort of a silly reason; but, then, if we are anything it is irrational.