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When measuring progress for the environment, we consider four headline dimensions - The natural landscape; The human environment; Oceans and estuaries; and International environmental concerns. It is difficult to obtain national time series data that encapsulate the changes in Australia's natural resources. However, for those dimensions where such data are available, progress over the past decade was varied.
The natural landscape - biodiversity, land, and inland waters
No single indicator can hope to encapsulate biodiversity, and so we focus on two aspects: the numbers of extinct and threatened Australian birds and mammals; and the clearing of native vegetation.
Although the numbers of threatened birds and mammals are only a small part of the overall biological diversity, a decline in these groups of species threatens ecological processes and can point to a wider decline in biodiversity. The list should not be construed as a census of threatened species as they can be added to or removed from the list as their status changes or due to improved knowledge (Endnote 7). However, it is as accurate an accounting of the status of these species as can be currently compiled.
Between 1994 and 2004 the number of terrestrial bird and mammal species assessed as extinct, endangered or vulnerable rose by 39% from 120 to 167 (of which 66 were birds and 101 were mammals). Much of this increase took place between 1997 and 2000 and was driven mainly by the increase in the numbers of vulnerable birds and mammals. In June 2004 just under half of these species were vulnerable, one-third were more seriously threatened (endangered) and the remaining fifth were presumed extinct. There were increases in the numbers of both endangered and vulnerable species, but the rise in species assessed as vulnerable was much higher (86%) than those assessed as endangered (22%).
Land clearing destroys plants and local ecosystems and removes the food and habitat on which other native species rely. Clearing helps weeds and invasive animals to spread, causes greenhouse gas emissions and can lead to soil degradation, such as erosion and salinity, which in turn can harm water quality. Native bushland has cultural, aesthetic and recreational importance to many Australians. The land clearing estimates include information about forest conversion (land cleared for the first time) and reclearing, both of which have environmental impacts.
Land clearance decreased by about 40% between 1991 and 2001. The area of land protected in national parks and the like increased. In 2001, an estimated 248,000 ha of Australian land was cleared, down from 415,000 ha cleared in 1991. Less than half of the land cleared in 2001 (120,000 ha) was ‘converted’ (cleared for the first time), which is less than half the area converted in 1991. The figures do not distinguish between the kinds of vegetation cleared.
Australia's soils are old and shallow, and are susceptible to degradation by agricultural activities. Salinity occurs when the water table rises, bringing natural salts to the surface (in sufficient quantity, these salts are toxic to most plants). When trees or other deep-rooted vegetation are replaced with vegetation that uses less water, the water table may rise to cause dryland salinity. Dryland salinity threatens biodiversity, through loss of habitat on land and in water, and also impacts on water resources, pipelines, houses and roads. Areas near water are often worst affected because they occupy the lowest parts of the landscape where saline groundwater first reaches the surface.
In 2000, about 46,500 sq kms (4.6 million hectares) of agricultural land were already affected with a high salinity hazard or in an area at high risk from shallow watertables. The cost to agricultural productivity was estimated at $187 million, which was less than the cost of other forms of soil degradation, such as $1.5 billion due to acidity in the same year.
However, the costs of salinity go further as it can impact on structures, as well as flora and fauna. The salt contained in rising groundwater levels can damage bitumen and concrete and so affect roads, footpaths, housing, pipelines and other assets. In 2000, about 11,800 kms of streams and lake edges, as well as 1,600 kms of rail and 19,900 kms of roads were affected or at risk. By 2050, these figures could rise to 41,300 kms of stream and lake edges, and 5,100 km of rail and 67,400 kms of road according to projections published by the National Land and Water Resources Audit in 2001. (Endnote 9).
Water is fundamental to the survival of people and other organisms. Apart from drinking water, much of our economy (agriculture in particular) relies on water. The condition of freshwater ecosystems has a critical impact on the wider environment.
In 2000, about 11% of Australia’s surface water management areas were overdeveloped. Another 15% were approaching sustainable extraction limits (i.e. highly developed). Therefore, in 2000 about one-quarter of Australia's surface water management areas were classed as highly used or overused. This proportion was greater for groundwater management units, where 11% were overdeveloped, and a further 19% were highly developed (Endnote 10). Detailed national time series data are not available, but a variety of partial evidence points to a decline in the quality of some of Australia's waterways.
The human environment
Human settlements have an impact on the landscape and seascape that surrounds them. They can also provide a home for native plants and animals. But the environmental quality of settlements is perhaps most important because it has an influence on those who live and work within them. Several environmental concerns are associated with human settlements. It is difficult to conceive an ideal headline indicator which might measure progress against each and so we choose one. For about a decade, the Australian public has been more concerned about air pollution than about any other environmental problem.
Overall, air quality in Australia is relatively good and has generally improved during the 1990s, although there has been a rise in recorded fine particle (PM10) concentrations (Endnote 11) after 2001 mainly due to irregular events, such as forest fires. Even so, our cities do not suffer from the acute pollution problems found in many OECD countries. It is important to note that daily changes in air quality depend on ambient conditions, like wind direction and the monitoring station's proximity to pollution sources. Further, high concentrations of fine particles from irregular events, such as forest fires, can obscure the longer trend in levels produced by regular sources, like car emissions.
The 2002 peak of about six days in the graph for selected urban areas was mainly due to severe forest fires and dust storms around the Sydney area where the National Environment Protection Measures (NEPM) goal was exceeded on 13 days that year. The goal was also exceeded on six days in Brisbane in 2002, while Melbourne, Perth and Adelaide recorded two, one and no such days respectively that year. There was a decline in 2003, even though bush fires and dust storms also caused the NEPM goal to be exceeded on 10 days in Melbourne, while Sydney recorded six days. However, Brisbane and Perth only recorded one day each that exceeded the goal in 2003, and Adelaide recorded no such days.
Oceans and estuaries
Australia’s coastal and marine regions support a large range of species, many of them found only in Australian waters. The marine environment is also important to Australian society and the economy. Many of the ways in which we use our oceans, beaches and estuaries can affect the quality of the ocean’s water and the diversity of life within it. Although this dimension has no headline indicator, it does have important aspects which different organisations have attempted to measure.
One such measure is the Estuarine Condition Index, developed by the National Land and Water Resources Audit (NLWRA). The index assesses the condition of about 1,000 estuaries around the Australian coast. Because estuaries occur at the borders of marine and freshwater ecosystems, they are influenced by the tides and also by fresh water from the land. And so measuring the condition of estuaries not only reports on the state of our oceans, it sheds light on how land use around the water that flows into the estuary is affecting the sea. The more modified an estuary the greater the pressures on it; in 2002 the NLWRA assessed estuary conditions as:
International environmental concerns
The health of our environment depends largely on the actions of Australians. But some environmental concerns transcend national boundaries: our environment can be influenced by the actions of other countries, and we, in turn, can influence other countries' environments. Our contribution to these international concerns is an important aspect of progress. Global warming is widely perceived as the most significant international environmental concern and Australia's greenhouse gas emissions are the focus of the headline indicator.
The main gases in the atmosphere, nitrogen and oxygen, are almost completely transparent to the sun's rays. But water vapour, carbon dioxide and other gases form a blanket around the Earth, trapping heat - a process called the greenhouse effect. Human activity is increasing atmospheric concentrations of existing greenhouse gases (such as carbon dioxide and methane) and adding new gases such as chlorofluorocarbons (CFCs). Net emissions are estimated using information about total emissions, less any credits from forest sinks (the credits are estimates of how much carbon dioxide has been absorbed by new and expanding forests established in Australia since 1990).
Australia's total net greenhouse emissions in 2002 were about 550 megatonnes (Mt) CO2 equivalent (Endnote 12), an increase of 8.8% since 1992. Emissions generally rose over most of the period, with the sharpest rise (about 5%) between 1997 and 1998. There was a slight decline in emissions during the next three years to 2001. This was followed by an increase of 1.5% between 2001 and 2002, which returned total net greenhouse emissions to their 1998 level (550 Mt CO2 equivalent).