Expected changes in Antarctic wind patterns may speed up global sea level rise, threatening coastal cities and low-lying countries around the world, a new study has warned.
Climate scientists have already resigned to the fact that sea levels, driven by melting ice sheets and glaciers around the world, will rise. It will mean that entire countries will eventually be lost to the sea.
However, now it is feared that coastal winds, which are thought to be strengthening because of a hole in the ozone layer above Antarctica, may rapidly speed up this process.
“When we first saw the results it was quite a shock. It was one of the few cases where I hoped the science was wrong,” said study lead author Paul Spence, of the ARC Centre of Excellence for Climate System Science.
Spence and his colleagues from the Australian National University and the University of New South Wales are the first team to factor these changing winds into Antarctic climate models.
Troublingly, they found the changing currents would push water up to 4C warmer than current temperatures to meet the base of exposed Antarctic ice shelves.
“This relatively warm water provides a huge reservoir of melt potential right near the grounding lines of ice shelves around Antarctica,” Spence explained.
“It could lead to a massive increase in the rate of ice sheet melt, with direct consequences for global sea level rise.”
The Intergovernmental Panel on Climate Change (IPCC) has warned that global sea levels could rise by between 26 and 82 centimetres (0.85-2.7ft) by the end of the century if stronger efforts are not made to curb climate change.
However, scientists were forced to reconsider this forecast, after more recent studies confirmed the irreversible collapse of the West Antarctic ice sheet has already begun.
This process means that potentially devastating eventual sea levels rise of up to 4 metres (13ft) is guaranteed. It was estimated that the process would take between 200 and 500 years, but now this prediction may have to be revised also.
Axel Timmerman, Professor of oceanography at University of Hawaii and an IPCC lead author who was not involved in the new Australian study, added, “It is very plausible that the mechanism revealed by this research will push parts of the West Antarctic Ice Sheet beyond a point of no return.
“This work suggests the Antarctic ice sheets may be less stable to future climate change than previously assumed.”
Small island states that are doomed to ‘drown’, as the impacts of climate change take hold, have been forced to resort to desperate measures. Kiribati recently purchased 20 sq km of land on Vanua Levu, a nearby Fijian island, to eventually relocate its people.
“If you were buying land in Australia and wanting to pass it down to your kids or your grandchildren, I suggest it’s a couple of metres above sea level,” Paul Spence added.
Photo: Mark Sykes via Flickr