Antarctica. The bottom of the world. On average, the coldest, driest and most elevated region the planet. Antarctica contains approximately 90% of the ice found on Earth. As a consequence, the goings-on in this extremely remote locale impact the rest of the globe. Understanding what happens here is critical to understanding the changing climate. Unfortunately, our current picture of the events on the continent is far from clear.
Most of the controversy lies in discerning what exactly is going on with the ice. Observations from the Arctic show that ice there is getting thinner and summer melting is proceeding more rapidly and to a greater extent than previously observed. Some claim that this was being offset by increasing ice in the Antarctic (e.g. here and here). Other studies suggest that the Antarctic as a whole is losing mass. The question is important because of the implications of melting ice sheets on global sea level rise.
Part of the controversy arises because the results depend on where the measurements are taken. The East Antarctic ice sheet, the world's largest, is apparently stable. However, West Antarctic and the Antarctic Peninsula have been less so. In 2002 a large portion of the Larsen B ice shelf collapsed in dramatic fashion. Recent satellite images also show that portions of West Antarctica approximately the size of California melted in January 2005 (image). Studies also show that glaciers on the Antarctic Peninsula are moving more quickly into the ocean over the last 10-15 years. These trends are alarming, and suggest that sea level could rise more quickly than anticipated in IPCC AR4.
The Southern Ocean which surrounds Antarctica also plays an important role in regulating the climate. This region is also undergoing modification as well. This ocean plays a role as a carbon sink, removing CO2 from the atmosphere. Recent reports have suggested that this sink is not as efficient as it once was, potentially leading to an extra enhancement of CO2 in the future. The suspected causes of this are human activities: the ozone hole and climate change. As an offset of sorts, though, the shedding of icebergs off Antarctica could help to reduce CO2 levels in the atmosphere. The icebergs act as floating estuaries, impacting the ecology and chemistry of the surrounding ocean. Phytoplankton around the icebergs capture CO2, removing it from the ocean and allowing the ocean to absorb more CO2.
An experiment is planned near the Antarctic Peninsula in early-2009 to attempt to exploit this characteristic of plankton. The idea is to fertilize the ocean with iron to encourage plankton growth. As has been noted before, this geo-engineering project reeks of humanity's hubris, and is more likely than not to end badly through some unforeseen consequence.
The various interactions and relationships between ice, ocean and atmosphere are complicated. Antarctica also provides the opportunity for us to better understand these processes. Ice cores from the continent has pushed the paleo-climate record back to 800 000 years, the longest available. A series of underground lakes has also been discovered in the last decade or so. Careful study of these lakes, which have been undisturbed and isolated from the atmosphere, may lead to new insights into many of the biological and physical processes occurring in the region.
Antarctica is unique in the world, critical to the global climate and (relatively) unspoilt by humanity. It presents an opportunity for humans to learn more of the world around us -- a way to plan for adaptation to and/or mitigation of our accelerating climate crisis. It unique status arises in part from the outstanding Antarctic Treaty, which prohibits territorial claims and militarization of the continent. As the climate warms and the region becomes more accessible, we must avoid a repeat of the debacle we are witnessing in the Arctic, with the rush by several nations to claim the regions of the Arctic for nationalistic resource exploitation, particularly oil. We must move away from our addiction to oil. In order for mankind to have a future,this sort of selfish short-term thinking must be avoided, while embracing a sustainable, one-planet paradigm. It is the only way forward.