Issue: Environment - Atmosphere, climate and oceans
This is an issue under the Australian Antarctic Territory theme of the Data Reporting System.
Why we need to know about this issue
Antarctica plays a key role in regulating the world's weather, climate and oceanic processes. Antarctica and the high-latitude Southern Ocean are especially important to Australia because of their proximity, their influence on regional climate processes, and the significance of the Southern Ocean to our fisheries.
Antarctica is also important as an early warning system for environmental changes for the rest of the world.
Indicators
- AAT-01 Monthly mean air temperature anomalies at Australian Antarctic stations
This condition indicator is important in that it provides an indication of the impact of climate change on temperatures in Australia's Antarctic Territory. This is particularly important for the flow on effects on ecosystems and the extent of ice and sea levels. - AAT-04 Concentrations of greenhouse gases
The three gases, carbon dioxide, methane and nitrous oxide together contribute around 70% of the anthropogenic greenhouse forcing. Changes at high southern latitudes is an unambiguous indication of global change. - AAT-05 Average deep water temperatures
The sinking of dense water near Antarctica forms part of an 'overturning' or 'conveyor belt' pattern of oceans currents that influences global and regional climates. Any changes in these measurements can influence a large region of the ocean in just a few years. The conveyor belt influences climate by carrying heat around the globe, absorbing carbon dioxide and carrying oxygen to the deep ocean. - AAT-06 Average deep water salinity
The sinking of dense water near Antarctica forms part of an 'overturning' or 'conveyor belt' pattern of oceans currents that influences global and regional climates. Any changes in these measurements can influence a large region of the ocean in just a few years. The conveyor belt influences climate by carrying heat around the globe, absorbing carbon dioxide and carrying oxygen to the deep ocean. - A-01 Annual variation in the Southern Oscillation Index
A number of studies indicate that the El Niño-Southern Oscillation (ENSO) explains 30 - 40% of the year-to-year variability of Australia's climate, particularly rainfall. The Southern Oscillation Index (SOI) is a well-established measure of this phenomenon. El Niño events are associated with below-normal rainfall and often drought over much of northern and eastern Australia. They generally occur every two to seven years and are generally followed by La Niña events, which are associated with higher rainfall. Changes in the timing of these events may be indicative of longer term changes in climate which may have significant impacts on the Antarctic continent. - A-12 Trend in the area of the ozone hole
The largest ozone depletions have occurred over Antarctica. The hole is the region, the so-called 'ozone hole' is defined where total ozone levels are less than 220 Dobson units. The cause of ozone depletion from the 1980s has been the steady accumulation of stratospheric chlorine and bromine compounds. This is particularly the case over Antarctica in spring because of the presence of ice nuclei (polar stratospheric clouds) and weak Antarctica sunlight, which provide a very efficient mechanism for ozone depletion. Trends in the size of the ozone hole is a direct measure of this pressure on the Antarctic continent.
Related issues
- Atmosphere - Climate variability and change - Weather
- Atmosphere - Climate variability and change - Greenhouse
- Atmosphere - Stratospheric ozone - General stratospheric ozone
Key
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