Assessments

The environment of Antarctica is changing, and there are increasing pressures on the ecosystem from variability and trends in weather and climate patterns, and the state of the ocean.

Nations continue to work cooperatively to protect the Antarctic environment.

There are encouraging signs that some key species that have been under threat are recovering. However, the populations of some species are still decreasing.

Benefits humans derive from Antarctic ecosystems include food provision, carbon capture, nutrient cycling, research, aesthetic experiences, tourism and recreation.

Annual average temperatures have generally increased throughout Antarctica since 1957, with the most marked warming occurring in the Antarctic Peninsula region and West Antarctica.

Despite signs of recovery in ozone, there is a general cooling trend, due mainly to the effect of increasing greenhouse gas concentrations.

There are signs of recovery (increased concentration of ozone) in spring and summer above Antarctica, but there is also significant interannual variability because of meteorological factors. Stronger signs of ozone recovery are expected during coming years.

A slight increase in overall areal coverage since 1979, but made up of contrasting regional and seasonal contributions. A sudden shift to high variability in 2012–20, with record highs followed by record lows (after 2016). Attribution remains uncertain.

Decreased duration of annual sea ice coverage in the Amundsen, Bellingshausen and north-west Weddell seas since 1979; increased duration in the Ross Sea; and mixed signals across East Antarctica.

A small, marginally significant decrease in circumantarctic fast ice extent for 2000–18.

Insufficient information to date to determine whether large-scale sea ice and snow cover thickness is changing around Antarctica.

Indications of a net mass loss over 2012–17, although this is not statistically significant.

Glaciers are generally retreating.

Temperature changes have been mixed in magnitude, and depend on depth and geographic region.

Polar pH levels are changing twice as fast as in the tropical ocean. Pre-industrial acidity has increased; pH has changed from pH 8.2 to pH 8.1.

The surface waters have freshened in recent decades.

Global sea levels are rising because of uptake of heat, and run-off from ice caps and glaciers. The rate of change shows regional and global variation with time because of certain aspects of climate variability.

Since the eradication of rodents and rabbits, the island’s vegetation is overall making a notable recovery. Macquarie cushion plants and many bryophyte species are still suffering some dieback.

Species composition is changing. Increasing mortality causes reduction of abundance in extensively vegetated areas. Loss of habitat for associated microinvertebrates. Some lichen habitat is expanding. Continued loss of moss banks and associated habitat.

All but one albatross species are endangered. Seabird deaths in Australian fisheries and in the Conservation of Antarctic Marine Living Resources area are greatly reduced, but seabirds continue to interact at unsustainable levels with fisheries outside Australia’s jurisdiction.

Status and trends vary with species and location. Population data, if available, cover only limited areas. At Macquarie Island, several petrel species have returned to the island since eradication of non-native predators.

Penguins are relatively well studied. Many populations appear to be stable or increasing, but, at Macquarie Island, gentoo penguins appear to be decreasing.

Because of their distribution and behaviours, it is difficult to assess populations of true seals in Antarctica. The last comprehensive seal survey occurred in 1999–2000.

Status and trends vary with species and location. At Macquarie Island, the small populations of fur seals appear to be stable, but elephant seals are still in decline.

Some species have recovered well since whaling ceased in the Southern Ocean, whereas for others there are no signs of recovery. For many species, population data are difficult to acquire.

Killer whales are the best studied toothed whales. However, uncertainties about their taxonomy make population assessments difficult.

Regular pre-recruit surveys, tagging studies and biennial stock assessments provide relatively high levels of information on current status and trends of fished stocks in Australia’s jurisdiction. Current stock levels are above (Macquarie Island) or just below (Heard Island and McDonald Islands) the long-term target level prescribed in the harvest strategy.

Data for this species are limited. Declines in illegal, unreported and unregulated fishing, and recent research in an exploratory fishery indicate that stocks off the Australian Antarctic Territory are healthy.

Annual surveys and stock assessments provide relatively high levels of information on current status and trends of this species at Heard Island and McDonald Islands. Current fishing levels are sustainable.

The human footprint is increasing through modernisation of stations and logistical requirements.

The amount of waste returned to Australia depends on the cargo limits of ships and varies from year to year.

Return of recyclable waste increased by 73% to 111 t over the past 5 years.

The amount of water required varies with the number of people and operational activities.

Quantity of fuel used is high but relatively steady at all stations.

Fuel use is highly variable at all stations. Increase in fuel use at Casey and Davis stations due to increased activities.

Use of electricity is linked to fuel use. The loss of wind turbines increased electricity production by diesel.

Vessels transport goods and people, and undertake marine science voyages. Annual fuel consumption varies, and depends on the number of voyages and sea ice conditions.

This is variable from year to year and is dependent on quantities of goods and numbers of people transported by aircraft.

Remediation work is continuing and progressing.

Management plans are in place for all protected areas.

Climate change is ongoing and increasingly affects Antarctic ecosystems.

Marine pollution is a global challenge; although Antarctica is still less affected than other regions, micro- and nano-plastics have been detected in the food web.

All commercial fisheries in the Southern Ocean are managed by the Commission on the Conservation of Antarctic Marine Living Resources, which applies an ecosystem-based management approach. Exploratory fisheries for toothfish operate in East Antarctica.

Impacts of tourism vary with the site visited. Some sites receive many more visitors than others.

Eradication of non-native introductions (e.g. rabbits and rodents on Macquarie Island) has been successful.

Invasive plants may be spreading.

Management plans are in place and are reviewed regularly. Natural and cultural heritage values are being preserved.

Australia’s Antarctic environmental management policy for the Australian Antarctic Territory and its external territories in the subantarctic is consistent with Australia’s obligations under the Antarctic Treaty.