Land, biodiversity, water and air are integral parts of Australia's environment and are inextricably linked. For example, changes in the health of inland waters, such as reduced river flow, can affect biodiversity, while changes in land use can affect inland waters and biodiversity. Not only do Australia's plants, animals and ecosystems sustain life, but they are also key contributors to economic growth as inputs to production.
The Land and biodiversity section outlines the unique biodiversity in Australia and the pressures placed on it, including the loss of habitat caused by land clearing and the adverse impact on native species by weeds and pests. It also examines measures for the conservation of biodiversity including the management of threatened species and the establishment of protected areas.
Water is fundamental to the survival of people and organisms and is a valuable resource for much of our economy, especially agriculture. Australia's rainfall varies considerably year-to-year, season-to-season and region-to-region and water shortages and drought conditions experienced throughout much of Australia in recent years have exacerbated the pressure on water supplies. The Water section in this chapter provides information about water availability, storage and use.
The Air section examines both greenhouse gas (GHG) emissions and air quality. Greenhouse gases are a natural part of the atmosphere and maintain the Earth's surface temperature at levels able to support life by trapping warmth from the Sun. However, human activities, especially burning fossil fuels (coal, oil, gas) increase concentrations of greenhouse gases in the atmosphere. The enhanced greenhouse effect from greenhouse gas emissions has been implicated in climate change. The major contributors to GHG emissions and Australia's progress towards meeting its obligations under the Kyoto Protocol are discussed in this section. The discussion on air quality also looks at air pollutants such as carbon monoxide, ozone (photochemical smog) and particulate matter, all of which can have deleterious effects on the health of humans and other organisms.
The chapter contains an article on Australia's most important food-producing region, the Murray-Darling Basin.