At a glance
Pressures on the coastal zone are strongly related to catchment land use and development. In urban areas, the intensity of pressures is generally correlated with human population densities. Australia has continued to increase in population since the 2011 state of the environment report, and most of that growth has been on the coast. Pressures resulting from coastal urban areas include direct habitat destruction, hydrological modifications, pollution (organic, inorganic, light, sound and debris), and the construction of artificial structures and reefs. In general, the state of most of these pressures ranged from low to high impact, but has been worsening, during the past 5 years.
Pressures on coasts outside urban areas include those associated with resource extraction and agriculture. The commodities boom has increased pressures because of mining, and oil and gas production, particularly through the addition and maintenance of coastal infrastructure for processing and export. Some of this development has occurred or is planned for relatively remote areas, such as the north-west of Australia, affecting otherwise undeveloped coast. Agricultural land use replaces diverse native ecosystems with monospecific crops, and often increases the input of nutrients, sediments, acids, salts, herbicides and pesticides to nearby waterways. Although pressures related to resource extraction have grown in the past 5 years, their effects are generally localised. In contrast, increasing agriculture is having widespread impacts through habitat loss, diffuse pollution and changes to water availability.
Some pressures apply to all areas of the coast, although the impact of these pressures depends on the specific area and context. The most important of these overall pressures is climate change. Coasts are particularly sensitive to climate change because of rising sea levels, which are predicted to cause extensive erosion and inundation in coming decades. Since 2011, coasts have experienced more frequent and severe extreme weather events, such as heatwaves and large storms, and these have had significant ecological impacts. Attribution studies have been used to estimate how climate change is increasing the likelihood of such extreme weather events.