West
Antarctic ice loss has accelerated over past four years
Rate
of ice loss from West Antarctic has accelerated sharply, European
scientists say, causing global sea levels to rise by 15% more than
previously thought
23
December, 2013
Ice
is being lost over the West Antarctic ice sheet at a faster rate.
The
European Space Agency’s Cryosat – a satellite with a
radar altimeter that can peer through the clouds and see in the dark
– has
confirmed that 150 cubic kilometres of ice are drifting
into the Southern Ocean each year: a much faster rate than the
calculation for 2010.
After
observations between 2005 and 2010, gathered by 10 different
satellite missions, Antarctic scientists and oceanographers
calculated that the melting of ice from the West Antarctic peninsula
was causing global sea levels to rise by 0.28mm a year. The latest
survey suggests this rate is 15% higher.
The
figures were revealed at the autumn meeting of the American
Geophysical Union in San Francisco. Most of the ice loss
comes from glaciers flowing into the Amundsen Sea.
“We
find that ice thinning continues to be most pronounced along
fast-flowing ice streams of this sector and their tributaries, with
thinning rates of between four to eight metres per year near the
grounding lines – where the ice streams lift up off the land and
begin to float out over the ocean – of the Pine Island, Thwaites
and Smith glaciers,” said Malcolm McMillan of the University of
Leeds in the UK.
Wide-ranging
view
The
increase could be due to faster thinning – or it could be down to
more accurate measurement, because Cryosat has more advanced
instruments and circles the planet in a near-polar orbit, to cross
territory no other observers could hope to see.
Cryosat
will be followed by another series of European satellites, to be
launched from 2014 onwards. Each of these Sentinels –
that is their name – will have synthetic aperture radar instruments
that will monitor a 250 kilometre-wide strip of the globe with each
orbit.
They
will work in pairs and not just keep an eye on polar
ice but will cover Europe and Canada as well every one to
three days, and watch, too, the main shipping routes, whatever the
weather.
This
article was produced by the Climate
News Network
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