Climate Change and the Antarctic

Although the impact of climate change and the Arctic are discussed often in the media, climate change in the Antarctic is comparatively neglected, or reported misleadingly.The science, however, is clear: climate change is already negatively impacting Antarctica.

The West Antarctic Peninsula is one of the fastest warming areas on Earth, with only some areas of the Arctic Circle experiencing faster rising temperatures. However, since Antarctica is a big place, climate change is not having a uniform impact, with some areas experiencing increases in sea ice extent. Yet in others, sea ice is decreasing, with measurable impacts on wildlife. ASOC believes that understanding climate change impacts on Antarctica is a matter of critical importance for the world and for the continent itself.

Temperature trends in Antarctica between 1981 and 2007, based on thermal infrared observations made by a series of NOAA satellite sensors. Author: Robert Simmon, NASA Earth Observatory.

The Antarctic and Climate

Local Antarctic effects of climate change are only part of the problem. 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. Alterations to this system will affect climate all over the planet.

A map of West Antarctica with the West Antarctic Ice Sheet.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. 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 5 mm 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 (1.5–2 mm per year), but the uncertainty is large.

Antarctic species are dramatically impacted by climate as well. Krill often feed on algae underneath sea ice and populations have been declining around the West Antarctic Peninsula as sea ice has decreased. Adélie penguin populations have been declining in recent years due to reductions in krill populations and changing weather conditions in their traditional nesting areas. Emperor penguins are highly vulnerable as well and are predicted to suffer when the world's average temperature increases by 2 degrees Celsius. Furthermore, a 2008 study has additionally identified Antarctic toothfish as highly vulnerable to climate change. Climate change in Antarctica will thus have dramatic effects both globally and locally - and perhaps harm some of the world's most beloved species.

Antarctic surface temperature trends for 1957-2006. Author: NAS

Actions to Address Antarctic Climate Change

ASOC works to raise the profile of Antarctic climate change issues through public advocacy, attending Antarctic governance meetings, and conducting outreach to governments. Activities related to climate change should take place in four areas:

Reduction of greenhouse gas emissions: Widespread deployment of energy efficiency and renewable energy systems at all Antarctic stations, coordination of transport and logistics strategic planning about new facilities (necessity, location and design) can bring about regional and global environmental benefits as well as cost savings. Given that Antarctica is one of the regions of the world where the impacts of climate change are most apparent and pronounced, Antarctic Treaty Parties should lead by example in the global effort in addressing climate change.

Implementation of climate adaptation strategies: Strategies for reducing the vulnerability of climate sensitive ecosystems and organisms will be increasingly important as the rapid changes underway may exceed the natural abilities of many Antarctic organisms to cope. Strategies to increase the resilience of ecosystems include: establishing a representative network of marine protected areas, protecting areas which are less likely to change (refugia), such as the Ross Sea; implementing appropriate biosecurity measures; putting into place adaptive management systems which are able to incorporate uncertainty and to respond to new information, for example through the expansion and improvement of CCAMLR’s Ecosystem Monitoring Program (CEMP) and the establishment of a Southern Ocean Sentinel program.

Promotion of globally important climate science: ASOC acknowledges and supports the world-class climate research conducted by Antarctic researchers. We support the continued timely dissemination of these findings to policy makers and the world population in general. At the same time, we underline the importance of leading by example by minimizing the climate impacts of research and logistic activities through reducing greenhouse gas emissions wherever possible. The Scientific Committee on Antarctic Research has recently compiled an excellent report, Antarctic Climate Change and the Environment, summarizing the science on Antarctic climate change.

Designation of marine protected areas: Protecting large areas from fishing and pollution will provide refuges for vulnerable species whose habitat may be changing dramatically. The Ross Sea, an area that is expected to warm more slowly than the rest of the Antarctic, is a particularly important area for focus.

Ocean acidification is another important problem linked to rising levels of carbon dioxide.Read more about ocean acidification and the Southern Ocean here.