Delving in Antarctica
‘It is almost a reproach to civilization that we have arrived at the close of the nineteenth century without knowing the whole of the superficial appearance of this planet,’ declared an exasperated John Sutherland, Duke of Argyll and former Governor of Canada, in 1897. In spite of the huge progress made across science, technology, engineering and social reform during the Victorian era, the area surrounding the South Pole was unknown. Yet by 1913, a concerted push by the likes of Shackleton and Scott for Britain, Amundsen for Norway, Mawson for Australasia, Filchner for Germany and Shirase for Japan, had reached the South and flung open the door on Antarctica. A frozen continent shaped by climatic extremes and inhabited by wildlife and vegetation unknown to science was being uncovered.
We now know Antarctica and the surrounding Southern Ocean play a hugely significant role in our planet’s climate. By helping regulate the global exchange of heat and carbon dioxide, subtle changes in the region can have far reaching consequences. Importantly, over ninety-eight percent of the continent is covered by three large ice sheets which have an average thickness of 2,300 metres (around 7,500 feet). This equates to a vast amount of fresh water, estimated to be of the order of 70 per cent of world supplies. Some is of immense age, laid down as snow and turned to ice over 880,000 years ago. In the past, however, large-scale melting of Antarctic ice has taken place during periods of sustained warming, driving global sea-level rise. Importantly, Antarctica continues to experience change, seemingly not all of it natural, with some parts of the continent warming five times faster than the world average.
|Arriving in Antarctica|
As part of a research program led by the University of New South Wales (and involving the University of Exeter), Dr Chris Fogwill and myself will be working on the Atlantic-facing part of West Antarctic Ice Sheet during January 2011, thanks to funding from the Australian Research Council and supported by Antarctic Logistics and Expeditions. The WAIS is an example of a marine based ice sheet, with the main bulk of its ice (equivalent to a global rise in sea level of around 3.3 metres) grounded well below mean sea level. As a result, the WAIS may be highly vulnerable to future warming. Studies of previous periods of warming suggest if the grounding line retreats, this can trigger a strong positive feedback where the surrounding ocean water bathing the ice sheet triggers separation from the bedrock. The UN’s Intergovernmental Panel on Climate Change (the IPCC), however, regards the loss of the WAIS as high risk because of the possible rise in sea level, but of low probability because warmer air temperatures may increase snowfall in Antarctica, compensating for any loss from increased coastal melting. To help reduce this future uncertainty, we will be investigating how West Antarctica has responded to temperature changes in the recent geological past.
Our scientific exploration will focus on the Ellsworth Mountains, reaching up to 4,892 metres above sea level. At an average temperature of -30˚C, this is a challenging environment in which to undertake research. Yet frozen within the rock and ice of this spectacular range lie crucial clues to the history and future of this great continent in the south. Our work will be on the mountains that protrude through the ice sheet at a strategic junction between the floating Ronne Ice Shelf and continental ice, using exposed rock as a dipstick to establish the thickness of ice and how it’s been thinning over the last twelve thousand years.
The timetable for our fieldwork can be found at www.christurney.com. If you fancy following us more closely, we’ll be twittering away on @ProfChrisTurney during our Antarctic fieldwork, describing the conditions and progress of work in the traditional 140 characters or less. Hope you can join us.