November 24, 2014

expert reaction to research on Antarctic sea ice

Researchers have published in the journal Nature Geoscience their efforts to map the thickness of sea ice in the Antarctic using an autonomous underwater vehicle. The team provide new estimates for characteristics of the Antarctic sea ice, and suggest that it may in fact be thicker than previous estimates proposed.

Dr David Ferreira, Oceanographer at the University of Reading, said:

“The quality and density of these observations are truly outstanding. This literally adds a new dimension to our knowledge of the Antarctic sea ice. The frustration is that we do not have more measurements like these.

“Because Antarctic sea ice melts and refreezes every year, we tend to think of it as relatively thin and smooth, a view that was not challenged by the few measurements available up to now. This latest discovery reveals a much richer and more exciting picture, one of a more dynamically active ice pack than previously thought.

“These findings call for a rethinking of the interaction between ocean and atmosphere around Antarctica and how it is represented in our climate models. Several processes, such as the movements of winds, and the transfer of heat from the ocean to the atmosphere, go through the sea ice and are critically dependent on its thickness.

“This research provides a formidable benchmark to evaluate our climate models in this region. We strongly depend on the simulation of the sea ice in these models to test possible causes of the Antarctic sea ice expansion. Effects of the ozone hole, of melt water from the Antarctic ice sheet, or of sea ice movements are among the plausible candidates, but we are limited by the quality of our models in this poorly observed region of the world to discriminate between them.”

Prof Mike Meredith, Deputy Director of Science at the British Antarctic Survey, said:

“Sea ice is changing in both polar regions, with important consequences for climate and the ecosystem. In contrast to the Arctic, the changes around Antarctica vary from region to region, but full understanding of the causes and impacts of these changes requires detailed knowledge of how thick the ice is, which has historically proven very hard to get.

“Satellites can now give information about this over large areas, but proper interpretation of the satellite data requires direct measurements also. This new paper presents important results obtained from a novel underwater vehicle that radically change our concepts of the structure of Antarctic sea ice, and the processes that influence it.  Such understanding is key to improving our models of how sea ice will change into the future.”

‘Thick and deformed Antarctic sea ice mapped with autonomous underwater vehicles’ by G. Williams et al. published in Nature Geoscience on Monday 24 November. 

Declared interests

None declared