Waking the giant: Global Warming in the Weddell Sea, West Antarctic Ice Sheet and sea level rise

Warm ocean currents are projected to melt the Filchner-Ronne Ice Shelf in the Weddell Sea area of Antarctica opening instabilities in the West Antarctic Ice sheet (WAIS) which will impact global sea level rise. Climate change is waking up the sleeping giant of Antarctica.

Significant scientific research has been published in recent weeks on the impact of global warming on changing wind patterns and southern ocean currents and the flow-on impact on Antarctic ice shelves and glaciers. The most recent studies reveal the potential instability of the Filchner-Ronne Ice Shelf in the Weddell Sea area. But the real questions to be asked concern the long term stability of the West Antarctic Ice Sheet (WAIS) and how rapidly it could collapse raising global sea levels by up to 6 metres.

I highlighted in November 2011 that the Thwaites and Pine Island Glaciers accelerating, West Antarctic Ice Sheet losing mass in the Amundsen Sea area. Now climate researchers of the Alfred Wegener Institute for Polar and Marine Research in the Helmholtz Association studying the opposite side of the West Antarctic Ice Sheet (WAIS) in the Weddell Sea area have discovered a mechanism which will drive warm ocean water towards the coast in the later decades of this century, allowing a higher rate of basal melting - the melting from underneath of ice shelves and glaciers by warmer ocean currents - leading to greater discharge of ice from the icesheet.

Another research team has found a large deep basin, about 20,000 square kilometres in size and up to 2 kilometres deep, underneath the ice sheet in the Weddell Sea area, which makes the ice sheet inherently unstable if pinion points for the ice shelf retreat and warmer water enters the basin.

Attenborough warns of ice shelf destruction in Antarctica

UK Naturalist and documentary maker David Attenborough has warned about the implications of melting ice sheets in the polar regions but emphasised the changes under way in Antarctica "is likely to have the most dramatic effects of all".

His comments were made in a November 2011 article in the BBC Radio Times reported by the Independent newspaper. While the title of the Independent newspaper article - Warning over melting ice at North Pole - places emphasis on processes in the Arctic, the important statement by Attenborough is about the collapse of ice shelves fringing Antarctica and the implications for the West Antarctic Ice Sheet.

Global Warming in Antarctica: Thwaites and Pine Island Glaciers accelerating, West Antarctic Ice Sheet losing mass

Scientists have been studying the climate change impacts on ice shelfs and glaciers for some time in Antarctica, and particularly around the Antarctic Peninsula where there is substantial warming occurring increasing ice shelf melt and the speed and discharge of glaciers. The most recent studies predict a faster retreat for the Thwaites Glacier and that warm ocean currents are already speeding the melting of the Pine Island Glacier and Ice Shelf and Getz Ice Shelf. A NASA Icebridge flight detected a major new rift in the Pine Island ice shelf on October 14 - the start of the calving of a massive iceberg. A recent paper in Nature Geoscience discusses the Stability of the West Antarctic ice sheet in a warming world and the likelihood of collapse that would raise sea level by more than three metres over the course of several centuries or less.

Related: The Wilkins ice Bridge collapsed in April 2009 as Polar regions felt the heat of climate change. I reported as far back as 2004 that warming in Antarctica was cause for concern with ocean food chain crashing due to Antarctic warming. More recently in April 2011 I discussed Penguin numbers suffering with krill decline due to Global Warming.