Melting of Antarctica’s ice shelves to intensify

Under both high and intermediate emissions rates, their models suggest a doubling of surface melting by 2050.

The study also sets aside the Fifth Assessment Report of the UN’s Intergovernmental Panel on Climate Change (IPCC) that predicted that the Antarctic ice sheet would contribute only 5-cm to global sea-level rise by the end of 2100. They form a natural barrier blocking inland ice flow to the oceans.

If we lose Antarctica’s ice shelves, he says, the impact is irreversible.

The findings showed that warming of the climate caused due to greenhouse gas emissions has the potential of doubling the Antarctica-wide ice sheet surface melting by 2050.

However, according to a study published Monday in the journal Nature Geoscience, if fossil fuel consumption maintains its current rate, Antarctica may experience a widespread collapse of its ice shelves, which could spur significant sea level rise.

“Our new models include processes that take place when ice sheets come into contact with the ocean”, said Golledge.

Floating extensions of the continental ice sheets are known as ice shelves.

To avoid the loss of the Antarctic ice shelves, and an associated commitment to many metres of sea-level rise, the study showed atmospheric warming had to be kept below 2C above present levels.

The direct contribution of melting ice shelves to sea level rise is minimal, but their presence slows the rate of meltwater entering the ocean. Since 10% of the world population lives on sea coast, any rise in water levels would lead to global havoc, he said.

Global sea levels will rise substantially more than previously thought and nearly irreversibly if greenhouse gas emissions continue, according to New Zealand-led research released on Thursday.

“A lot of people are out there saying there’s no point – we’re in that world now where it’s all going to happen”, said researcher Dr Chris Fogwill of the Climate Change Research Centre at the University of New South Wales.

Co-author Tim Naish says in order to restrict global warming to 2C the Paris meeting must agree to reduce global Carbon dioxide emissions to zero before the end of the century.

“The reality is that what we’re doing now in terms of greenhouse gas emissions is essentially setting up the climate for warming that will persist for centuries and probably millennia”.

That commitment has been criticised by a few climate scientists and environmental groups, and a recent Oxfam report described it as falling “well short” of a fair contribution towards limiting the global temperature rise to 2C. Another, put forth by former NASA Scientist James Hansen this summer, argued that glacial melting will “likely” occur this century and could cause as much as a ten foot sea-level rise in as little as fifty years.

This would trigger a collapse that would go on for thousands of years, raising sea levels by 0.6 metres to 3 metres by the year 2300 depending on how high manmade greenhouse gas emissions remain.

But the IPCC only included a five centimetre contribution from melting Antarctic ice because of uncertainty over how the Antarctic ice sheet would respond to future warming. “We’re now on track for a global temperature rise of a couple of degrees which will take us into that ballpark, so there may well be a few scary surprises in store for us, possibly within just a few hundred years”.