In a Comment published in the journal Nature on 15 March 2018 by John C. Moore and Rupert Gladstone of the Arctic Centre, University of Lapland with colleagues from CSC – the Finnish IT Center for Science and Princeton University, USA, argue that applying targeted geoengineering to preserve the ice sheets is a topic worthy of serious research and investment in Antarctic infrastructure.

By 2100, most large coastal cities will face sea
levels that are more than a metre higher than currently. For example, a 0.5-metre
rise in Guangzhou, China, would displace more than 1 million people; a 2-metre rise
would affect more than 2 million. Without coastal protection, the global cost of
damages could reach US$50 trillion a year. Sea walls and flood defences cost tens of
billions of dollars a year to construct and maintain.

The
ice sheets of Greenland and Antarctica will contribute more to sea-level rise this
century than any other source, stalling the fastest flows of ice into the oceans
would buy us a few centuries to deal with climate change and protect coasts.

“Just a few very fast flowing glaciers in Greenland and
Antarctica drain much of the ice sheets, and will be the route for ice that will
raise sea levels. These glaciers are tens of kilometres across, and so attractive
targets to stabilize rather than building walls around the world’s coastline”,
explains John Moore, Research Professor at University
of Lapland and Chief Scientist in Beijing Normal University, China.

The glaciers could be slowed in 3 ways: warm ocean waters could be
prevented from reaching their bases and accelerating melting; the ice shelves where
they start to float could be buttressed by building artificial islands in the sea;
and the glacier beds could be dried by draining or freezing the thin film of water
they slide on. “Advanced ice/ocean computer modelling helps to evaluate the
effectiveness of these ideas”, says Thomas Zwinger,
Application Scientist at CSC.
"Antarctic-Ice.jpg"
The engineering costs and scales
of these projects are comparable with today’s large civil engineering projects, but
with extra challenges due to the remote and harsh polar environment. Artificial
islands have been built such as Hong Kong new airport; water is drained into rock
tunnels beneath a glacier in Norway to feed a hydropower plant; raising a berm in
front of the fastest flowing glacier in Greenland would need a wall only 5 km across
and 100 m high.

Potential risks, especially to local
ecosystems, need careful field work and computer modelling, the glaciers need their
beds and melt rates mapping and improvements in climate model simulations of the
Southern Ocean and the North Atlantic’s flow onto the Greenland shelf are required.
In our view, however, the greatest risk is doing nothing — or if the interventions
don’t work. The impacts of construction would be dwarfed locally by the effects of
the ice sheet’s collapse, and globally by rapid sea-level rise. Geoengineering of
glaciers will not mitigate global warming from greenhouse gases. The fate of the ice
sheets will depend ultimately on how quickly we bring down emissions. If they peak
soon, it should be possible to preserve the ice sheets until they are again viable.
If emissions keep rising, the aim will become managing the collapse of the ice
sheets to smooth the rate of sea level rise and ease adaptation.

Further information:

John Moore, University of Lapland, Arctic Centre john.moore.bnu(at)gmail.com, +358
400 194 850

Thomas Zwinger, CSC – IT center for Science,
thomas.zwinger(at)csc.fi, +358 50 381 9538

John C. Moore, Rupert Gladstone, Thomas Zwinger and
Michael Wolovick: Geoengineer polar glaciers to slow sea-level rise. Nature, 15
March 2018, vol 555.

 

LaY/AK/JM&JW