The
world's biggest ice sheet could cause "several metres" of sea-level
rise over centuries if the global temperature rises more than 2oC,
according to a British study published Wednesday.
Researchers at
Durham University concluded that if global greenhouse emissions remain
high, the melting East Antarctica Ice Sheet (EAIS) could cause nearly
half a metre of sea-level rise by 2100. Their analysis was published in
the scientific journal Nature.
If emissions remain high beyond that,
the EAIS could contribute around one to three metres to global sea
levels by 2300 and two to five metres by 2500, they said.
However, if
emissions were dramatically reduced, EAIS could contribute around two
centimetres of sea level rise by 2100, according to the assessment. This
would represent far less than the ice loss expected from Greenland and
West Antarctica.
"A key conclusion from our analysis is that the fate
of the East Antarctic Ice Sheet remains very much in our hands," said
lead author Chris Stokes, from Durham University's Department of
Geography.
"This ice sheet is by far the largest on the planet,
containing the equivalent of 52 metres of sea level and it's really
important that we do not awaken this sleeping giant.
"Restricting
global temperature increases to below the 2oC limit set by the Paris
Climate Agreement should mean that we avoid the worst-case scenarios or
perhaps even halt the melting of the East Antarctic Ice Sheet and
therefore limit its impact on global sea level rise," he added.
The study did note that the worst scenarios projected were "very unlikely".
World
leaders agreed at the 2015 UN Climate Change Conference in Paris to
limit global warming to well below 2oC and pursue efforts to limit the
rise to 1.5oC.
The research team, which included scientists from the
UK, Australia, France and the US analysed how the ice sheet responded to
past warm periods when making their predictions.
They ran computer
simulations to model the effects of different greenhouse gas emission
levels and temperatures on the ice sheet by the years 2100, 2300 and
2500. They found evidence to suggest that three million years ago, when
temperatures were around 2-4oC higher than present, part of the EAIS
"collapsed and contributed several metres to sea-level rise".
"Even
as recently as 400,000 years ago -- not that long ago on geological
timescales -- there is evidence that a part of the EAIS retreated 700 km
inland in response to only 1-2oC of global warming," they added.
Nerilie
Abram, a co-author of the study from the Australian National University
in Canberra, warned the sheet "isn't as stable and protected as we once
thought."
