Key findings

Antarctic environment

Antarctica is warming, although changes in atmospheric circulation brought about by the Antarctic ozone hole have been a temporary mitigating factor that has reduced the overall amount of warming, primarily in summer

During the past half-century, western Antarctic surface temperatures have shown general warming trends, with significant regional patterns. Cooling of the lower stratosphere because of ozone depletion in spring and early summer has helped to mitigate the amount of warming during the past 20–30 years, particularly during the summer across East Antarctica. For the remainder of the century, the effects of global climate change because of increased greenhouse gas concentrations are likely to overcome the mitigating effects of ozone depletion as the ozone layer recovers.

2016

Relates to

Antarctic environment

In contrast to the West Antarctic Ice Sheet, the East Antarctic Ice Sheet is not losing mass overall but may be gaining mass. In some places at the coastal margins, the ice sheet is showing variability in response to changes in ocean heat. Antarctic glacier discharge shows high variability, while glacier retreat continues on Heard Island

Although the Antarctic ice sheet is losing mass overall, this is occurring in West Antarctica and the Antarctic Peninsula. Various studies show that East Antarctica, as a whole, is close to neutral or possibly gaining mass. This aggregate conceals regional patterns of ice gain and loss in East Antarctica. In particular, coastal ice discharge from the Totten Glacier shows high variability that is related to changes in ocean heat. Recent research shows that the Totten Glacier drains a large region that rests on bedrock below sea level. This makes the ice sheet potentially vulnerable to ice retreat and ice losses, as is currently seen in parts of West Antarctica. Glacier retreat continues to be observed on Heard Island.

2016

Relates to

Antarctic environment

Major regional changes are occurring in Antarctic sea ice coverage

For the past 30 years, there has been a small increase in the extent of sea ice around Antarctica, but with strong regional differences. Most notable are contrasting regional changes in sea ice seasonality attributed to changing patterns of large-scale atmospheric circulation. In the western Antarctic Peninsula region, there is mounting evidence that a shortening of the ice season has affected multiple levels of the marine food web. In contrast, there is a trend towards lengthening of the annual sea ice season in the western Ross Sea sector. The situation in the East Antarctic sea ice zone is variable and complex, and is currently under investigation.

2016

Relates to

Antarctic environment

Global sea levels continue to rise, although patterns of sea level change across the Southern Ocean are variable because of regional differences in heat uptake and transport. The Southern Ocean continues to become warmer

Global sea levels are rising, but regional patterns and rates of change are variable because of particular modes of climate variability that influence heat uptake and transport. In the region from 35°S to 65°S, the upper Southern Ocean has warmed by 0.2 °C since the 1950s. This rate of warming is faster than elsewhere in the global ocean. Warmer waters enable species to extend their range southwards. These immigrating species are less specialised for the cold environment than Antarctic species, and are likely to outcompete, and perhaps replace, the local native species. This could have a significant impact, particularly on benthic (ocean floor) communities and ecosystem functioning.

2016

Relates to

Antarctic environment

Several factors, such as ocean acidification, increasing wind strength and changes in ocean circulation in the Southern Ocean, may affect the base of Antarctic food webs

Dissolved carbon dioxide acidifies the ocean and reduces the availability of carbonate ions that shell-making organisms require for calcification, reducing the ability of these organisms to form shells. This may affect their reproductive capabilities and recruitment. Changes in the physical environment may alter the species composition of planktonic communities, as well as the way that carbon cycles from the atmosphere through the marine ecosystems.

2016

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Antarctic environment

Antarctic terrestrial ecosystems are changing, especially where snowfall is replaced by rain

Retreating glaciers, higher ambient temperatures and precipitation as rain rather than snow make the terrestrial environment more accessible to plant and microbial communities. A warmer climate and increased availability of liquid water enable the populations of some species to expand and non-native species to become established.

2016

Relates to

Antarctic environment

Antarctic vertebrates are highly specialised to survive in the Antarctic. Population trends vary greatly among regions, even within the same species

Antarctic vertebrates encompass a variety of flying seabirds and penguins, several seal and whale species, and numerous fish. Around the Antarctic Peninsula, an apparent decrease in the abundance of Antarctic krill may have been caused by a reduction in winter sea ice coverage. This has caused a decrease in Adélie and chinstrap penguin populations. In comparison, Adélie penguin populations in East Antarctica may have increased. The reasons for this are currently unknown.

2016

Relates to

Antarctic environment

The environment of subantarctic islands is also changing. Most noticeable is the retreat of the glaciers at Heard Island. At Macquarie Island, the most important change had been to the natural heritage, which had suffered under the impact of introduced mammals, but a large-scale eradication program has been completed successfully

From 1947 to 2008, the glacier area on Heard Island decreased by 20 per cent. Since 2008, only relatively little data are available for the assessment of the glaciers on the island, but further evidence of glacial retreat has been observed. Introduced vertebrates, such as cats, rats, mice and rabbits, previously caused a major deterioration of the natural heritage values of Macquarie Island. There was significant predation of native species until feral cats were eradicated in 2002. Overgrazing by European rabbits caused an increase in landslides, many of which damaged seabird colonies. A large-scale eradication program completed in 2014 successfully eradicated rabbits, rats and mice from the island.

2016

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Antarctic environment

The pressure of human activities on Antarctica and the Southern Ocean is increasing

The areas affected by human activities in the region continue to increase. New stations are being built, and tourism to the continent continues to grow on the Antarctic Peninsula, but is still insignificant in East Antarctica. With a growing world population, commercial fishing activities are likely to expand. Adequate resources are needed to monitor the intensity, frequency and impacts of all human activities. The Protocol on Environmental Protection to the Antarctic Treaty commits signatories to comprehensive protection of the Antarctic environment. Australia has ratified the protocol by establishing legislation to enforce procedures for reducing the impacts of Australians visiting Antarctica, and has taken practical steps to reduce the impacts of past activities, such as the clean-up of abandoned waste-disposal sites.

2016

Relates to

Antarctic environment

Klekociuk A, Wienecke B (2016). Antarctic environment: Key findings. In: Australia state of the environment 2016, Australian Government Department of the Environment and Energy, Canberra, https://soe.environment.gov.au/theme/antarctic-environment/key-findings?year=96, DOI 10.4226/94/58b65b2b307c0

Australia State of the Environment Report

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Key findings

Antarctica is warming, although changes in atmospheric circulation brought about by the Antarctic ozone hole have been a temporary mitigating factor that has reduced the overall amount of warming, primarily in summer

Major regional changes are occurring in Antarctic sea ice coverage

Global sea levels continue to rise, although patterns of sea level change across the Southern Ocean are variable because of regional differences in heat uptake and transport. The Southern Ocean continues to become warmer

Several factors, such as ocean acidification, increasing wind strength and changes in ocean circulation in the Southern Ocean, may affect the base of Antarctic food webs

Antarctic terrestrial ecosystems are changing, especially where snowfall is replaced by rain

Antarctic vertebrates are highly specialised to survive in the Antarctic. Population trends vary greatly among regions, even within the same species

The pressure of human activities on Antarctica and the Southern Ocean is increasing

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Key findings

Antarctica is warming, although changes in atmospheric circulation brought about by the Antarctic ozone hole have been a temporary mitigating factor that has reduced the overall amount of warming, primarily in summer

Major regional changes are occurring in Antarctic sea ice coverage

Global sea levels continue to rise, although patterns of sea level change across the Southern Ocean are variable because of regional differences in heat uptake and transport. The Southern Ocean continues to become warmer

Several factors, such as ocean acidification, increasing wind strength and changes in ocean circulation in the Southern Ocean, may affect the base of Antarctic food webs

Antarctic terrestrial ecosystems are changing, especially where snowfall is replaced by rain

Antarctic vertebrates are highly specialised to survive in the Antarctic. Population trends vary greatly among regions, even within the same species

The pressure of human activities on Antarctica and the Southern Ocean is increasing

More information

Authors

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Acknowledgment of Country

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