Pressures
Pressures
Pressures arising from natural and human causes. The legacy impacts of pressures that were more intensive in the past, such as water diversion and land clearing at large scales, are also examined.
Overview for Pressures
To understand the state and trends of Australia’s environment, it is necessary to consider both the historical pressures that have had a profound impact on the environment, and the contemporary pressures that directly and indirectly influence the state of the environment. Historical changes to ecosystems and heritage places set the context for the current state of our environment, and—in many instances—their influences persist. For example, pressure on the environment from land clearing and fragmentation of habitat in Australia includes a legacy of extensive historical clearing. Since European settlement, some 13 per cent of native vegetation has been completely converted for land use, and a further 62 per cent is subject to varying degrees of disturbance.
Many of the contemporary pressures on the Australian environment have increased over time as the drivers of population change and economic activity have increased the demand for food, fibre, minerals, land, transport and energy, and have increased our waste generation.
The main pressures facing the Australian environment in 2016 are the same as those reported in SoE 2011: climate change, land-use change, habitat fragmentation and degradation, and invasive species. Land-use change, habitat fragmentation and invasive species are effects that have been accumulating during the past century or more. In comparison, pressures associated with climate change have only recently had a significant detectable impact.
Although some individual pressures have decreased, such as those associated with air quality, poor agricultural practices, commercial fishing, and oil and gas exploration and production in the marine environment, there is no indication that the major pressures outlined in SoE 2011 have decreased.
SoE 2016 describes a range of other pressures on the Australian environment, including altered fire regimes, overuse of species and habitats, ocean acidification, pollution in our coastal and marine environments, energy production, mining and agriculture. More detail on these pressures is available in the thematic reports.
An image depicting how overlapping, cumulative pressures amplify the threat to the environment. Examples are given for a coral reef and for agricultural land. For instance, extra sediment, climate change and human activities such as fishing and shipping form overlapping, cumulative pressures that can bleach corals and kill fish and reefs while encouraging the spread of invasive species.
At a glance
Australian ambient air quality is mostly affected by increasing human activity and climate change.
The population of Australia’s major cities continues to increase, with both increasing urban density and expanding boundaries. The corresponding increase in emissions from transport, energy and resource use, and the concentration of these emissions—for example, in traffic congestion—put ongoing pressure on air quality.
Wood smoke from domestic wood heaters remains a major pressure on winter air quality in many regions (contributing 50 per cent or more to levels of fine particulate matter), with no effective controls yet implemented because of social and political complexities.
Longstanding pressures are present from industrial, commercial, domestic, on-road and off-road emissions. Increasing focus is on the pressure from nonregulated sources, such as nonroad diesel engines and equipment (including shipping and rail transport), as well as nonroad spark-ignition engines and equipment such as gardening equipment.
Climate change is also a pressure on air quality. The increasing prevalence of extreme heatwaves has an impact on the chemical reactivity of the atmosphere, promoting the formation of photochemical smog. In addition, an increase in heatwaves increases the risk of fire, leading to a greater impact of smoke on Australia’s airsheds; and changes in rainfall could lead to reduced precipitation and drought, promoting dust events. Increased temperatures cause human discomfort, encouraging people to seek mitigation from cooling systems, which places pressure on power requirements and emissions to the atmosphere.
At a glance
A range of pressures on the built environment have a high or very high impact on livability, human health and/or urban environmental efficiency.
Pressures from a growing population have a high impact on the urban footprint, because of a lack of coordinated and integrated urban planning for both infill and greenfield development across Australia’s cities. Our cities are experiencing urban sprawl as more land on city fringes is taken to accommodate an increased population (although this is decreasing because of rapid growth in development in inner urban areas).
Traffic congestion continues to be a problem, with the avoidable cost of congestion (where the benefits to road users of some travel in congested conditions are less than the costs imposed on other road users and the wider community) for Australian capital cities growing from about $12.8 billion in 2010 to around $16.5 billion in 2014–15. Although improvements in public transport aim to alleviate transport issues, and per-person car use has begun to decline, the bulk of urban passenger travel is, and will continue to be for the foreseeable future, by private motor vehicles.
Australian cities consume a large amount of natural resources, although the consumption of energy by the residential sector has been slower than population growth during recent years, and water use by manufacturing, and the commercial and services industries has shown an overall decrease since 2010–11. The pollution associated with consumption continues to affect our land, air and water. The amount of waste sent to landfill is decreasing; however, the amount of hazardous waste produced is increasing. Air pollution is generally relatively low in our cities, but is still a health concern, particularly for particulate matter. The hard surfaces of our cities contribute to water pollution, with urban run-off carrying topsoil, chemicals, rubbish, nutrients, oil and grease into waterways.
Climate change—and its intersection with increased population, urbanisation and residential shifts to high-risk areas—is considered to be high impact and worsening. Increased frequency of extreme weather events, such as heatwaves and storms, will particularly affect urban areas, and sea level rise will affect our coastal cities.
At a glance
Greenhouse gases (GHGs)—carbon dioxide (CO2), methane, short-lived tropospheric and stratospheric ozone, nitrous oxide and synthetic GHGs—together with water vapour, and natural and industrial aerosols, influence Earth’s energy balance. Human activity, primarily the burning of fossil fuels during the past 250 years, has caused well-quantified increases in the concentrations of GHGs in the atmosphere, resulting in significant increases in positive radiative forcing, which has a warming effect on climate. CO2 levels in our atmosphere have increased by 43 per cent from pre-industrial (1750) levels, and methane levels have increased by 152 per cent. The contributions of CO2 and methane to radiative forcing have increased since 1995.
Australia’s emissions of CO2 per person in 2013 were nearly twice the average of countries in the Organisation for Economic Co-operation and Development. This reflects Australia’s heavy reliance on fossil fuels as a primary energy source and, particularly, the role of coal in the production of electricity. The energy sector continues to be the dominant source of Australia’s GHG emissions, accounting for 76 per cent of net emissions in 2015. Within the energy sector, 52 per cent of emissions arise from electricity generation and 17 per cent from transport. The energy sector contributed 93.9 per cent of CO2 emissions in the 2015 inventory, whereas the agriculture sector contributed 59.3 per cent of methane emissions and 72 per cent of nitrous oxide emissions.
Between 1990 and 2015, Australia’s GHG emissions decreased by 27 per cent per person, and, in 2012, Australia met its commitments under the Kyoto Protocol by limiting increases in net GHG emissions to 103 per cent of its 1990 levels from 2008 to 2012. However, climate projections suggest that GHG emissions will continue to put pressure on our climate.
At a glance
The drivers of the condition of Australia’s environment (including heritage) are both historical and contemporary. Historical pressures, such as a legacy of land clearing and changes in land use, cannot be addressed through short-term management. Other pressures, such as rising temperature or changes to rainfall patterns or fire regimes, warrant responses even though the root cause cannot be removed.
Contemporary pressures such as climate change, population growth and economic growth affect Australia’s heritage generally, and have some specific consequences for natural, Indigenous and historic heritage. The effects of environmental drivers are interrelated—for example, altered fire regimes or invasive species directly affect natural heritage, but may also have consequences for cultural heritage, because of their effect on Indigenous cultural heritage practices, and historical land-use patterns and cultural landscapes.
Climate change is leading to higher temperatures, more rainfall in northern Australia and less elsewhere, rising sea level, increasing frequency and intensity of wildfires, more soil erosion, additional damage from extreme weather events, and degradation caused by intensified ocean acidification. These climate change pressures have high impact and will irreversibly damage Australia’s heritage in the absence of remedial action.
Changes to population may reduce resources for conservation in rural areas while creating pressure for change and development in coastal and urban areas. Development pressures create tension between economic values and cultural values. Both inconsistent decision-making and differing perceptions of heritage value between communities and governments can lead to statutes, policies and outcomes that adversely affect heritage. Individual sites may also be subject to neglect and vandalism or, conversely, damage from increased visitation.
Economic growth affects heritage through development projects that threaten heritage places, large-scale resource extraction and growing tourism—which may itself be associated with heritage values. Economic growth can have positive effects, including creation of employment, and support for communities and traditional cultural practices, but can also lead to altered resource allocation, such as an emphasis on providing visitor facilities or opportunities within reserved lands at the expense of conservation of heritage values. Localised decline may also result in the loss of significant original uses of heritage buildings, works, places and landscapes.
Pressures particular to natural heritage include invasive species, progressive loss of habitat (including loss of ecological connectivity), conflicting land use, and tension between the potential economic value of land and its dedication for conservation purposes.
Indigenous heritage in Australia remains under pressure from loss of knowledge and tradition, despite resurgence and reconnection in some areas and communities. Intangible Indigenous culture also continues to be threatened by disconnection between people and place, loss of language, and discontinuation of cultural practices, particularly where changing values and expectations of the growing proportion of young Indigenous people may not align with traditional values or systems. Indigenous sites continue to be threatened by incremental destruction associated with urban and industrial development, which is often approved despite heritage impacts being identified.
Historic heritage is particularly at risk from pressures for redevelopment on both large and small scales. The impacts range from complete destruction to inappropriate change and adverse effects on associated attributes such as visual setting. Other pressures include those that arise from population shift, including redundancy, neglect and decay. However, there is also greater recognition of the value of historic buildings and opportunities that can be provided by their adaptive re-use. The decline in professional and trade skills in the historic heritage sector, and the ageing specialist workforce and rise of nonspecialist tradespeople present a looming threat.
At a glance
The pressures affecting biodiversity remain largely consistent with those identified in the 1996, 2001, 2006 and 2011 state of the environment reports.
The most significant current pressures are clearing, fragmentation and declining quality of habitat; invasive species; climate change; changed fire regimes; grazing; and changed hydrology. Most of these exert a high to very high pressure on biodiversity, and are worsening. The cumulative and interacting effects of many of these pressures amplify the threat to biodiversity in Australia. Jurisdictional reports all note that their understanding of the full impact of these key pressures on biodiversity is low because of the inadequacy of long-term data and monitoring.
Clearing has stabilised across most states since 2011, except in Queensland. However, the legacy of past clearing means that its effects on biodiversity are not decreasing. High rates of population growth in urban and peri-urban areas result in continued conversion and degradation of the surrounding natural ecosystems.
The pressure from invasive species and pathogens continues a very high and worsening trend. Invasive plants and animals are the most frequently cited threats to species listed in the Environment Protection and Biodiversity Conservation Act 1999, and account for 12 of the 21 identified key threatening processes. Almost all states and territories note that data on the distribution and abundance of pest plants and animals, and management effectiveness for these pests are poor.
The impacts of a changing climate are increasingly clear, and include changes to ecosystem structure and composition, phenology (timing of lifecycle events), fire regimes and hydrology. Climate variability and climate change are also considered to have a high or very high impact, with a worsening trend in coastal, marine and inland water environments, and a range of impacts on aquatic biodiversity.
Livestock production is considered a major contributing factor to the decline of threatened mammals in northern Australia and, in conjunction with other pressures, contributes to changes in bird populations. However, the complete impact of grazing on biodiversity and ecosystem functioning is largely unknown.
At a glance
Although a changing climate has shaped the Australian landscape and its vegetation, the current rate of climate change is likely to result in changes in the distribution and composition of vegetation communities. Some communities are likely to disappear, and others will be transformed as different species mix together to form novel communities, in some of which exotic species are likely to play a significant role. Many agricultural and forestry systems are likely to be adversely affected.
Rates of land clearing, although decreasing in many states, are still increasing in some states in response to relaxation of legislative controls. There is recognition that land clearing can affect environmental services, such as control of erosion and maintenance of soil quality, and that habitat fragmentation, which is a typical consequence of land clearing, places increased pressures on the survival of remnant patches of natural vegetation.
Widespread landscape-scale pressures (including invasive species and changed bushfire regimes) continue to threaten land managed for environmental values, conservation and extensive agriculture. Bushfire frequencies are increasing, as are the number of invasive species that are threatening Australian landscapes and industries. Increasing resistance of invasive weeds to herbicides is recognised as a growing problem. Pressures on the land environment associated with grazing—Australia’s most extensive land use—have decreased somewhat, with a decrease in the size of the national cattle herd and in the area grazed.
Although better management of many agricultural systems has reduced their impacts on the land environment, a number of issues relating to nutrient and soil management remain. Low-tillage conservation agriculture approaches have been successful, but uptake appears to be declining in some areas. Management of native and plantation forestry faces challenges as the industry ceases to expand, and the delivery of long-term management agreements falls short of expectations.
Urban and peri-urban expansion continues to threaten agricultural land and the viability of some horticultural industries. Legislative approaches are in place in some jurisdictions to help manage these tensions.
Mining developments have slowed in recent years, although the management of former mining sites is an emerging concern. So too is the expansion of unconventional gas extraction, particularly because of concerns about safety, but also because of competition for land with other uses.
Waste production continues to increase, although recycling and re-use are also increasing, in some cases supported by innovative commercial opportunities for recycled products.
At a glance
Overall, the key pressures affecting inland water environments have changed little since 2011, with climatic and pest-based pressures increasing, land-use and management pressures remaining largely stable, and some stabilisation occurring in the pressure of water resources development.
This period provided the first cooler than average year since 2001, along with the warmest, third-warmest and fifth-warmest years on record for Australia. It also included 2011 as the second-wettest year on record, whereas recent years have produced significant record rainfall deficiencies in parts of Australia.
Invasive species pressures include those from cane toads, common carp, gambusia, goldfish, and various Weeds of National Significance. Cane toads have reportedly spread into the Kimberley and upper reaches of the Fitzroy River in Western Australia, while 2 aquatic weeds (sagittaria/arrowhead and water hyacinth) were added to the Weeds of National Significance list in 2012.
No recent water-affecting land-use or management changes have been observed on a nationally significant scale. The broadest land-cover effects on water quality since 2010–11 are likely to have arisen from post–La Niña fires in savanna and rangeland areas. About 50–70 million hectares of the northern savannas burn each year, contributing to the ongoing tropical aquatic ecosystem pressures. In addition, Queensland’s land-clearing rate of nearly 300,000 hectares per year exceeds all other states and territories combined.
Urban water consumption figures from larger centres have generally increased. To assist in meeting demands, Australia’s climate-resilient water sources (desalination and recycled water plants) produced more than 440 gigalitres (GL) in 2012–13, amounting to approximately 25 per cent of the estimated production capacity of 1821 GL. More than two-thirds of this was for urban use. Groundwater use for urban demand is not a large proportion of the total water supply for the country, although it continues to be a key supply resource for Perth and for many rural areas.
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.
At a glance
Australia’s marine environment is experiencing pressures from a wide range of sources that affect its habitats, communities, species and ecosystem functioning to varying degrees. With many pressures affecting the marine environment and its inhabitants at any one time, it can be difficult to attribute observed impacts to individual pressures. It is particularly difficult to understand or predict how individual pressures will interact and what the cumulative impacts will be.
The overarching pressure that is currently affecting the marine environment—and will continue to affect it even with reduction of greenhouse gas emissions—is climate change. Anthropogenically driven ocean warming, superimposed on natural climate variations, and ocean acidification pose risks to Australia’s coral reef ecosystems, and giant kelp and other habitats, including deep-ocean communities. Sea surface temperatures are continuing to increase nationally, with waters in the South-east and South-west marine regions increasing at a rate of more than 0.4 °C per decade. There is already evidence that, as waters have warmed, some species have shifted their distributions towards the poles, altering marine ecosystems. Changes to nutrient supply and dissolved oxygen are also projected to occur because of climate change; however, observations are insufficient at present to identify whether changes are occurring.
Extraction of resources—such as seafood, and oil and gas—from the marine environment is highly variable in its distribution and impacts. Many pressures associated with the extraction of resources are highly localised, and the likelihood of recovery of affected habitats, communities and species is high once the pressure is removed. Other pressures are more widespread or more persistent, or both, leaving little likelihood of recovery in the short to medium, and even long, term.
Overall, the footprint of pressures within Australian waters associated with commercial fishing has decreased in the past decade. Pressures associated with recreational fishing are generally stable, although, for some species, recreational catches now exceed commercial catches and are increasing. Pressures associated with the oil and gas industries, marine mining and dumping of waste tend to be localised, and are either stable, declining or increasing, but with the prospect that they may decline because of recent legislation.
Use of the marine environment by commercial and recreational vessels continues to increase. The risks associated with such activities that are not currently actively managed (e.g. anchor scour, ship strike, noise) are also increasing. High, but variable, concentrations of marine debris are found in all marine environments, and it is expected that marine debris will continue to be a ubiquitous problem because of continued growth in plastics production and use. As a result, marine debris has been identified as a key threatening process for marine vertebrate species. There is insufficient understanding of the long-term impacts of chronic noise in the marine environment, or trends in toxins, pesticides and herbicides.
At a glance
The climate of Antarctica is changing. Compared with conditions prevailing in the 1950s, parts of West Antarctica—particularly the Antarctic Peninsula region—have warmed. In East Antarctica, where Australia operates, temperatures have also increased, but to a lesser extent. Across Antarctica, many environmental observations show modest rates of change and large year-to-year variability, which limits the ability to ascribe significance to trends in most cases. However, changes have been observed, including increased maximum sea ice extent, strengthened westerly winds, altered ocean properties and thinning of some ice shelves, in addition to specific seasonal and regional trends in temperatures. These environmental changes—and our new understanding of the physical environment, bedrock, ice thickness and ocean–ice boundaries—suggest that further change is likely, with associated impacts on marine and terrestrial ecosystems. In some regions, changes mirroring those already under way in West Antarctica are possible, with potentially profound global impacts.
Globally, extreme weather events such as heatwaves, storm surges and increased precipitation are expected to increase in frequency and intensity as the planet warms. In certain regions at the periphery of Antarctica, rain is now occasionally falling where historically it only ever used to snow. These events are changing the Antarctic environment and may affect the biodiversity that has developed under a specific moisture regime. Climate change is also driving ocean acidification, which will affect many Antarctic marine species, including crucial species at the base of the food web.
Human activities are still increasing; new stations are being constructed, often in rare ice-free areas. Tourism is a major activity around the Antarctic Peninsula. Disturbance of habitat and wildlife, introduction of invasive plants and other alien organisms, and pollution are all risks linked to human presence on the continent. Marine debris, particularly plastics, is an increasing pressure on Antarctic species, causing mortality and morbidity through entanglement and ingestion. The debris comes both from human presence on the continent and human pollution throughout the rest of the planet, which makes its way to Antarctic regions. Worldwide demand for fishery products means that fishing and other legal or illegal extraction of resources are pressures on the Antarctic environment and its species.
Subantarctic islands are changing rapidly as rainfall patterns are changing, and glaciers at Heard Island are retreating and thinning. Although eradication efforts have successfully reduced the impact of introduced species on some islands, the changing climate is likely to pave the way for more invaders.
