ASOC Publications on the Antarctic and Climate Change:

Impacts of Climate Change on Antarctic Ecosystems

Global Climate Change, Antarctica, and Krill (article from the Antarctic Krill Conservation Project)

Climate Change and the Implementation of CCAMLR's Objectives (Paper from CCAMLR 2007)

The Antarctic and Climate Change (Paper from ATCM 2007)

The Antarctic and Climate Change (Paper from ATCM 2006)

The Antarctic and Climate Change (Paper from ATCM 2005)

A Short Bibliography, with abbreviated abstracts, on Antarctic Climate Change. Included are references to papers on " The meteorological viewpoint," " The past record from ice cores," "The collapse of the Larsen Ice Shelf," The West Antarctic Ice sheet (WAIS)," " The WAIS as a whole," and " The Antarctic ice sheet as a whole."

Summaries of SCAR Scientific Research Programmes

The Antarctic and Climate Change:  A Summary

Antarctica comprises two geologically distinct regions, East Antarctica and West Antarctica, separated by the great Trans-Antarctic Mountains but joined together by the all-encompassing ice sheet. The presence of the high ice sheet and the polar location make Antarctica a powerful heat sink that strongly affects the climate of the whole Earth. Furthermore, the annual sea ice cover around the continent, which seasonally reaches an area greater than that of the continent itself, modulates exchanges of heat, moisture, and gases between the atmosphere and ocean and, through salt rejection when it freezes, forces the formation of cold oceanic bottom waters that spread out under the world’s oceans.

Both the ice sheet and the sea ice are potentially subject to change in a changing climate; the ice sheet, in fact, may be changing now in response to past climate change. The greatest threat to the inhabited world comes from the West Antarctic ice sheet (WAIS), which rests on a bed far below sea level and so may have the potential for rapid shrinkage. The Antarctic is so vast, remote, and difficult to monitor, however, and the physical behavior of the ice sheet so complex, that there is as yet no definitive demonstration (or disproof) of such change, even though a pronounced climatic warming is ongoing in one northerly portion of the continent. Measurements from satellites early in the 21st century should settle the question of current growth or shrinkage, but prediction will remain problematic for many years. See C. R. Bentley. 2002. Antarctica. In T. Munn, ed., Encyclopedia of Global Environmental Change, Volume 1, The Earth system: physical and chemical dimensions of global environmental change, M. C MacCracken and J. S Perry, eds, John Wiley & Sons, 184–189.

The Antarctic ice sheet contains sufficient ice to raise world-wide sea level by more than 60 meters if melted completely. The amount of snow deposited annually on the ice sheet is equivalent to about 5mm of global sea level, as is the mean annual discharge of ice back into the ocean. Thus, a modest imbalance between the input and output of ice might be a major contributor to the present-day rise in sea level (1.5–2mm per year), but the uncertainty is large.

Despite all available measurements of snow accumulation, ice velocities, surface and basal melting, and iceberg discharge, it is still not known for certain whether the ice sheet is growing or shrinking. The uncertainty in the estimate of the total mass balance is at least 20% of the mass input, equivalent to a global sea-level change of about 1mm per year. Furthermore, the fact that rates of discharge from some of the Antarctic ice streams have changed markedly in recent decades and centuries suggests that the mass balance also may be rapidly changeable.

The volume and geographic extent of the Antarctic ice sheet certainly have undergone major changes over geological time. The ice sheet was significantly larger during the last glacial maximum, some 20,000 years ago, and retreated to near its present extent within the last several thousand years; that retreat is probably on-going at present. Several mechanisms in the ice-sheet–lithosphere system, notably post-glacial isostatic uplift and the effect of temperature on the viscosity of the ice in the deeper layers, have long response times. It is likely that the ice sheet is still reacting dynamically to the glacial–inter-glacial transition between 20,000 and 10,000 years ago and to the subsequent increase in the snow accumulation rate. Consequently, the present Antarctic contribution to sea-level change (whatever it may be) could reflect changes in the accumulation rate over the past 100 years, or the long-term dynamical response of the ice sheet, or both.

Future enhanced greenhouse warming will affect the mass balance of the ice sheet. Oceanic warming could increase basal melting of the floating ice shelves, whose thinning could result in faster flow of the ice into the ocean, contributing to sea-level rise. On the other hand, atmospheric warming and reduction in sea-ice cover almost surely will give rise to increased precipitation over the continent, thereby contributing to sea-level.

Realistic predictions of the response of Antarctica to enhanced greenhouse warming and the resulting sea-level contribution will not be possible until the present mass balance is determined and a better understanding of the atmosphere–ice–ocean processes and ice dynamics is developed. See C. R. Bentley, 2003. Mass balance of the Antarctic ice sheet: observational aspects. In J. L. Bamber and A. J. Payne, eds, Mass Balance of the Cryosphere: Observations and Modelling of Contemporary and Future Changes. Cambridge University Press, 459-489.


External Links:

The Scientific Committee on Antarctic Research (SCAR) is the international coordinating body for national programs of Antarctic research. International Scientific Research Programmes sponsored by SCAR: http://www.scar.org/researchgroups/

An extensive list of web sites on Arctic and Antarctic regions, and on Polar Research (from Scott Polar Research Institute): http://www.spri.cam.ac.uk/links/general.html

Photos and movies of the Larsen ice Shelf (from Scott Polar Research Institute): http://www.spri.cam.ac.uk/research/cpom/lis/

A description of the West Antarctic Ice Sheet research initiative, with many links (from Robert Bindschadler, NASA Goddard Space Flight Center): http://igloo.gsfc.nasa.gov/wais/