"Accelerated ice melt in west Antarctica is inevitable for the rest of the
century no matter how much carbon emissions are cut, research indicates. The
implications for sea level rise are “dire”, scientists say, and mean some
coastal cities may have to be abandoned.
The ice sheet of west Antarctica would push up the oceans by 5 metres if lost
completely. Previous studies have suggested it is doomed to collapse over the
course of centuries, but the new study shows that even drastic emissions cuts
in the coming decades will not slow the melting.
The analysis shows the rate of melting of the floating ice shelves in the
Amundsen Sea will be three times faster this century compared with the previous
century, even if the world meets the most ambitious Paris agreement target of
keeping global heating below 1.5C above pre-industrial levels.
Losing the floating ice shelves means the glacial ice sheets on land are freed
to slide more rapidly into the ocean. Many millions of people live in coastal
cities that are vulnerable to sea level rise, from New York to Mumbai to
Shanghai, and more than a third of the global population lives within 62 miles
(100km) of the coast.
The climate crisis is driving sea level rise by the melting of ice sheets and
glaciers and the thermal expansion of sea water. The biggest uncertainty in
future sea level rise is what will happen in Antarctica, the scientists say,
making planning to adapt to the rise very hard. Researchers said translation of
the new findings on ice melting into specific estimates of sea level rise was
“Our study is not great news – we may have lost control of west Antarctic ice
shelf melting over the 21st century,” said Dr Kaitlin Naughten, at the British
Antarctic Survey, who led the work. “It is one impact of climate change that we
are probably just going to have to adapt to, and very likely this means some
coastal communities will either have to build [defences] or be abandoned.”
Naughten said her research showed the situation was more perilous than
previously thought. “But we shouldn’t give up [on climate action] because even
if this particular impact is unavoidable, it is only one impact of climate
change,” she added. “Our actions likely will make a difference [to Antarctic
ice melting] in the 22nd century and beyond, but that’s a timescale that
probably none of us today will be around to see.”"
*** Xanni ***
Chief Scientist, Xanadu
Partner, Glass Wings
Manager, Serious Cybernetics