This report mainly focuses on the environment of areas administered by Australia (the Australian Antarctic Territory, and the Territory of Heard Island and McDonald Islands), subantarctic Macquarie Island (which is part of Tasmania) and the Southern Ocean adjacent to these areas. The Antarctic region is managed cooperatively through the international agreements of the Antarctic Treaty System, in which Australia is a leading participant. Although relatively distant from other continents, Antarctica and the surrounding Southern Ocean have far-reaching effects on the rest of the globe, because they are key drivers of Earth’s oceanic and atmospheric systems. In turn, again although the region is distant from permanently inhabited continents, Antarctica is under the influence of human activities just like any other continent. Human effects include direct influences—for example, the concentration of human activities in the ice-free areas inevitably affects the flora and fauna that use these limited areas as growth and breeding sites—and indirect influences, the most important of which is anthropogenic climate change.
Antarctica, the Southern Ocean and subantarctic islands are changing. The rate of change varies around the continent, but some areas—such as the Antarctic Peninsula—are changing faster than others. The most important factors contributing to physical change are warming of the ocean and the lower atmosphere, both of which are associated with increasing greenhouse gases, and cooling of the stratosphere, mainly from ozone depletion. Human activity is putting pressure on fisheries in the Southern Ocean and the ice-free areas of the continent. East Antarctica, where Australia operates, has so far changed comparatively slowly, but it, too, is changing. There is still little understanding about how various factors may interact. For example, although research has identified a link between the ozone hole and changes in atmospheric circulation over Antarctica, the response of the Southern Ocean and Antarctic sea ice to these changes is still under debate.
The rate at which the physical environment of the Antarctic region is changing appears to be faster than the rate at which organisms, especially those of a higher order, can adapt to the changes. Although many uncertainties still exist, the composition and abundance of fauna and flora are expected to alter if environmental change continues. An undesirable outcome would be that some species are lost because they are unable to adapt to changing conditions. Although a few species may benefit from the change (e.g. more breeding territory may become available as glaciers retreat), others may be outcompeted by species that can adapt to the changing ecosystems, or be replaced by species whose range is now extending from warmer climes into the Antarctic region.