Antarctic ‘at risk by 2100’

New research confirms the likelihood of a substantial rise in global sea-level in the future if greenhouse gas emissions continue, and highlights the moral significance of decisions made now about mitigating climate change.

‘Missing the 2C target will result in an Antarctic contribution to sea-level rise that could be up to 10 metres higher than today, ‘ Dr Golledge said.

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.

The warming oceans have the potential to melt the floating ice shelves from below and to destroy their buttressing effect on the ice sheets.

The emission controls required to prevent Antarctic ice shelf collapse are tougher than most are willing to consider, said Dr Fogwill.

Scientists say that the rapid rate of ice melting in Antarctica may put the stability of the continent at risk by 2100. The coastal shelves act as a protective wall, insulating continental ice sheets from ocean currents.

‘Our new models include processes that take place when ice sheets come into contact with the ocean, ‘ Dr Golledge said. Like a “cork in a bottle”, if ice shelves in Antarctica continuously collapsed and melted, it would theoretically cause ice to pour more and more into the ocean, and sea levels will rise at about 200 feet, a scientist says. And by 2100 the rate could surpass the point associated with ice shelf collapse.

Due to the very slow response of the massive Antarctic ice sheets to global warming, Antarctic contribution to sea level rise would be “unstoppable” for thousands of years, and could be as much as 10 metres by 5000, according to the model.

The new findings therefore raise an ethical decision for us all, according to Dr Golledge.

An global team, led by Victoria University researcher Nick Golledge, published results in Nature which show that only the most ambitious effort to curb emissions will stop Antarctica’s ice shelves from collapsing.

“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”.

The United Nations Climate Change Conference will be held in Paris later this year, which aims to get worldwide agreement on limiting climate change effects. “To be on track this will require a global commitment to 30 percent reduction, below year 1990 levels, by the year 2030”.

Think of it as the chocks under a wheel of an airplane, Dr Golledge says. “It becomes an issue of whether we choose to mitigate now for the benefit of future generations or adapt to a world in which shorelines are significantly re-drawn”.

Emissions peak at 2020; are halved by 2050 and are zero by 2100.

Dr Golledge says the last time CO₂ concentrations in the atmosphere were similar to present levels was about 3 million years ago.

The Earth is now experiencing one of the highest rates of sea level rise for thousands of years, linked to global warming. The latter scenario would keep average temperatures below 2°C above pre-industrial levels, but unmitigated climate change would warm the world by nearly 5°C by 2100, and by 8-10°C by 2300.