Humans drive many of the pressures on our environment. Our activities, settlements and use of resources all affect the environment and its assets in different ways. Assessment People-related pressures 2021 Population growth (despite reductions due to COVID-19), urban expansion, and associated land clearing and pollution continue to impact our environment, particularly in coastal areas where most Australians live. Habitat modification such as construction of seawalls, and recreational activities such as tourism and fishing can also have substantial negative effects on species and ecosystems. Assessments of impact range from low to very high Assessments of trend range from deteriorating to stable Related to United Nations Sustainable Development Goal targets 6.3, 8.4, 8.9, 11.3, 11.4, 11.6, 11.a, 12.1, 12.4, 14.1, 14.4, 15.1, 15.2, 15.5, 15.8 Legend How was this assessment made Share on Twitter Share on Facebook Share on Linkedin Share this link Urbanisation Australia’s urban areas continue to grow. The population grew from 24 million people in 2016 to 25.6 million as at 30 June 2020, with more than 76% living in major cities. It is estimated that Australia’s population will exceed 28.7 million by 2021 (Centre for Population 2021). Australia is a highly urbanised country, with most of the population growth in the past decade occurring in Australia’s 18 largest cities; 39% of the existing population is located in Melbourne and Sydney. The COVID-19 pandemic has slowed population growth in 2020. Modelling by the Australian Bureau of Statistics indicates that the population will be 31.8 million in 2040, 4% less than predicted, as a result of the impact of the pandemic. Much of Australia’s population growth has been driven by overseas immigration. Cities such as Sydney and Melbourne traditionally experience significant levels of immigration; however, urban planning and economic drivers have meant that many immigrants subsequently move out to other urban areas across Australia (sometimes called ‘out migration’). These trends are fluctuating, and Greater Sydney has experienced a lower rate of out migration in recent years. Many Indigenous people live in urban areas, and connecting to Country in these areas remains important (see Connection to Country). Increasing urban density, as well as urban sprawl, puts pressure on the natural environment and heritage. In the case of the urban environment (see also Livability), pressures include increased costs for new infrastructure (Garrard et al. 2015), reduced access to local services and jobs, higher transport and energy costs, reduced space to produce food, reduced walkability and increased social isolation (Garrard et al. 2015). For the natural environment and green spaces, pressures include land clearing, reduced green space, pollution and loss of biodiversity (PIA 2018). Biodiverse urban areas are valuable not only for the ecology that lives within them, but for the identity, health and wellbeing of urban citizens. The threats to biodiversity in terrestrial urban areas are fragmentation from urban sprawl, logging and agricultural expansion; vehicle strikes and dog attacks; and the impacts of climate change, including more intense bushfires, droughts and extreme heat events (ACF 2020). Coastal urban areas Coastal population growth has continued to rise since 2016. This trend has been exacerbated by relocations to coastal towns driven by the COVID-19 pandemic, enabled by new ‘work from home’ patterns and online communication. This population growth and coastal development are having a high and increasing impact on the coastal environment. Proliferation of artificial marine structures to support the activities of growing coastal populations has continued since 2016 (Bugnot et al. 2021), from wharfs, jetties, marinas and moorings to coastal defence structures such as seawalls, breakwaters and groynes. Modification and loss of habitats are one of the primary causes of global biodiversity loss (Didham et al. 2007). In coastal environments, replacement of natural habitats such as mangroves, seagrasses, sediments and rocky reefs with artificial structures directly impacts many ecosystems and may also hinder species movement, alter food webs (Clynick et al. 2007), and facilitate the establishment and spread of non-native species (Dafforn et al. 2012). In parts of Australia, more than 50% of estuarine coastlines are modified by artificial structures, most of which are associated with urban growth. Although more building is forecast, recent innovations in ecological engineering have incorporated the complex topographic features of natural habitats, such as rock pools, crevices and root structures, into new seawalls. Customised habitat modules have also been retrofitted to existing sea walls. For example, 900 units fitted across Sydney Harbour from late 2018 were inhabited by microscopic life and invertebrates within hours of installation. In just a few months, the modules were crowded with marine life (Strain et al. 2018). Urban resources Urban areas are increasingly consuming material and energy resources, requiring investment in associated infrastructure. Despite this, investment in transport, water and energy infrastructure has declined since its peak 8–10 years ago. Conversely, expenditure on telecommunications infrastructure has been steadily increasing over the past 3 decades (BITRE 2020). We are increasingly relying on ageing infrastructure, resulting in less efficient urban services that can waste finite resources such as water. There is a need to invest in new and innovative technology that not only supports the net zero economy but makes our urban areas cleaner and more livable (e.g. new recycled water technology and systems, alternative energy sources, distributed energy networks). Another significant issue relates to the ‘digital and urban divide’, where underinvestment in all forms of infrastructure is resulting in lower levels of service in some areas, with significant social impacts. These include educational implications for students during the pandemic, and a lack of water or sewer connections, resulting in substandard living conditions in some regional areas. Households remain the biggest users of energy in Australia. Although our overall energy consumption rose by 0.6% in 2018–19 (with most of the growth being in the mining sector), household use has declined by 2.2% since 2016–17 (see also Energy production). In Australia, residential energy use, combined with construction, transport, manufacturing, electricity, gas and water, account for 71% of the nation’s greenhouse gas emissions (DISER 2020a). Australian water consumption rates are some of the highest in the world, and the volume of water required for many of our urban environments continues to grow along with the population. The amount of water that can be supplied to our households depends on climatic conditions and government policy. Risks to water security associated with climate change present a challenge for both human and environmental wellbeing. Our water supply relies heavily on rainfall to replenish storages, streams and groundwater. Infrastructure Australia’s 2019 audit found that the reduction in average winter rainfall in south-western Australia has caused a 50% reduction in urban run-off over the past 50 years, leading to declining streamflows across the southern and south-eastern regions (Infrastructure Australia 2019). As a result of increasing significant drought conditions, river levels have fallen, water storage has significantly decreased, and soils have become drier, reducing agricultural productivity and the livability of communities across Australia. The significant water shortages have placed strain on urban areas, necessitating water restrictions. Water shortages have also led to an increased use of desalinisation as a water source. Land clearing Clearing of native vegetation is a major cause of habitat loss and fragmentation, as well as heritage and biodiversity decline. It has been implicated in the listing under the EPBC Act of 60% of Australia’s threatened species (Kearney et al. 2018). Land clearing can also lead to processes that degrade soils, such as erosion, salinisation, loss of organic matter and depleted fertility. The primary drivers of native vegetation clearing in Australia include expansion of land dedicated mainly to agriculture (see Agriculture) and, to a lesser extent, forestry and infrastructure (including urban development; see Urbanisation). Land clearing is also a significant contributor to greenhouse gas emissions, and, conversely, land can absorb emissions through vegetation regrowth. Between 2000 and 2017, 7.7 million hectares of habitat for terrestrial threatened species was cleared or substantially degraded, including 64,000 hectares of habitat for terrestrial migratory species, and 370,000 hectares of threatened ecological communities (Ward et al. 2019). In total, 1,390 terrestrial threatened species (85%) have experienced some habitat loss since 2000, with some losing substantial proportions of their habitat. Nine of the 10 threatened species that have lost the most habitat to clearing occur in Queensland (Ward et al. 2019). Significant degradation of threatened species habitats also occurs from land use such as grazing of native vegetation. Land clearing is monitored nationally to inform the National Greenhouse Accounts, in ways that are consistent with Australia’s international commitments to reduce emissions, track progress and report each year (DISER 2021c). Current methods of detecting native vegetation clearing tend to focus on woody vegetation, which is more readily detected using satellite and aerial remote sensing, although substantial areas of nonwoody native vegetation (e.g. native grasslands) can also be subjected to clearing. From 2015 to 2019, nearly 0.29 million hectares of primary forest was determined to have been cleared, as well as a further 1.8 million hectares of secondary forest (regrowth after previous clearing; see also Terrestrial ecosystems and native vegetation). This represents a 15% reduction in the amount of primary forest clearing, and virtually no change in the amount of secondary forest clearing compared with the previous 5 years (DISER 2021g, DISER 2021h). A small proportion can be attributed to non-native vegetation clearing for forestry or agricultural purposes, or removal of non-native invasive woody species. Over the same period, extensive areas of sparse woody vegetation losses were also recorded, averaging 2.27 million hectares per year, a loss rate that is 8% greater than in the previous 5 years. Although gains in sparse woody vegetation were greater than losses (averaging 2.35 million hectares per year over 2015–19), these gains were 14% less than in the previous 5 years. This difference is partly due to the recent drought that also impacted extensive areas of inland Australia. The combined pressures of climate and land-use change, and especially water availability in semi-arid regions, influence woody vegetation gains and losses (Liao et al. 2020). Over the nearly 30 years since 1990, more than 6.1 million hectares of primary forest has been cleared and converted to other land uses or regrown as secondary forest, some of which is subject to re-clearing (sometimes repeatedly). The total area of sustained regrowth as of 2019 was 4.13 million hectares. In addition, extensive areas of sparse woody and nonwoody vegetation have been cleared and converted to other uses, principally pastures, but the full extent of this conversion is not well documented. The ongoing, cumulative impact of native vegetation loss on natural capital values is substantial. It can be many decades before areas of sustained native vegetation regrowth or managed restoration provide good-quality wildlife habitat. Each state and territory monitors land clearing for the purpose of native vegetation and soil management, land-use planning, and infrastructure or urban development planning. Queensland and New South Wales dominate the pattern of vegetation loss or gain. Extensive areas of primary forest and regrowth forest were lost in Queensland (64% and 70% of the national total, respectively) and New South Wales (20% and 16% of the national total, respectively) from 2014 to 2019. The majority of forest clearing in Queensland is attributed to agriculture, such as conversion to pasture for stock grazing in the Brigalow Belt and Mulga Lands bioregions (Queensland Government 2021). In New South Wales, there has been a steady increase in clearing, presumably for agricultural purposes, but substantial areas of clearing were not authorised (DPIE 2021). Analysis of data on national forest and woodland loss by Ward et al. (2019) also concluded that substantial areas of nationally important habitats appear to have been cleared without an authorisation under the EPBC Act (Ward et al. 2019) (Figure 16). In terms of loss of vegetation in areas other than forest, Queensland had the highest loss of sparse woody vegetation from 2014 to 2019 (31% of the national total), followed by the Northern Territory (28%) and Western Australia (26%). These changes relate to a variety of causes, including ‘natural’ reduction of shrub or sparse woody vegetation from changes in rainfall patterns across Australia, as well as land use such as grazing of native vegetation, and fire. For example, 55% of all lost sparse woody vegetation in the Northern Territory was found to coincide with fire events (DISER 2021f). Figure 16 Areas of potential threatened species habitat and threatened ecological communities that were cleared, classed as compliant and noncompliant loss, 2000–17 Expand View Figure 16 Areas of potential threatened species habitat and threatened ecological communities that were cleared, classed as compliant and noncompliant loss, 2000–17 Note: Compliant loss occurs with a referral under the Environment Protection and Biodiversity Conservation Act 1999. Noncompliant loss occurs without a referral. Three panels highlight the southern Western Australia coast (left), Tasmania (middle) and northern Queensland coast (right). Source: Ward et al. (2019) Share on Twitter Share on Facebook Share on Linkedin Share this link Pollution Australia, particularly our urban areas, produces high levels of pollution (see also Industrial pollution) and waste. Australia has the second-highest rate of annual waste disposal per person (704 kg), behind the United States (771 kg), and our waste production continues to increase. Pollution, as part of overall pressure on the environment from Australia’s population, has had a high impact on urban areas over the past 5 years. There is increasing evidence that the volume of debris is expanding along Australia’s coasts, increasing the risks to habitats and fauna, and posing a range of threats to the health and, potentially, survival of organisms and ecosystems. Debris is composed of different materials and items, such as glass and plastic bottles, metal cans, cigarettes, plastic bags, balloons and rubber. Pressures on coastal environments from land-based debris leaking into waterways are very high and increasing. In Australia’s offshore marine waters, plastics and debris are also having a high and increasing impact, with increases in litter flows into oceans (Wilcox et al. 2020). It is estimated that there are at least 25 times more microplastics on the sea floor than floating on the ocean’s surface, with some 14 million tonnes of debris across the ocean floor (Barrett et al. 2020). A national map of marine debris has been created based on a decade of citizen science studies, which shows high (but variable) concentrations of marine debris in Australia’s coastal beach environments (Gacutan et al. 2021). Although some of Australia’s marine plastic pollution is carried on currents from neighbouring countries, most plastic pollution is generated domestically (Hardesty et al. 2016) and then trapped in the coastal environment (Olivelli et al. 2020). Although the remoteness of Antarctica, the subantarctic islands and the Southern Ocean means that they are less affected by marine pollution than other regions, ocean currents bring urban pollutants into their waters, especially lightweight plastic waste. The COVID-19 pandemic increased plastic pollution significantly worldwide from early 2020 through the use of huge quantities of single-use items (Ammendolia et al. 2021), adding to the danger faced by wildlife. Entanglement in plastics, such as ropes, nets and monofilaments used in commercial fishing operations, threatens at least 243 species worldwide. Young Antarctic fur seals (Arctocephalus gazella) can get caught in plastic materials; as the animals grow, the plastic gets tighter and cuts into their bodies (Pemberton et al. 1992). This is not only a macro-waste problem; microplastic and nanoplastic particles have been detected in the Antarctic food web. The pressure on Antarctic ecosystems posed by marine pollution is high and deteriorating. Air pollution is produced by a variety of sources, such as transport, commerce, industry and domestic activities, most of which are concentrated in or around urban areas. Levels of key pollutants affecting air quality and health increased in most Australian cities over the past 5 years (see Air). As our cities grow, this is resulting in more pollution, as well as more people being exposed to that pollution. Such population-based pressures on air quality can only be improved by a move to cleaner technologies such as electric vehicles, renewable energy sources and renewables-fuelled public transport. Since 2016, the pressure on air quality due to smoke from bushfires and prescribed burns has been very high and deteriorating (see Bushfires). Climate change and associated increases in temperature, heatwaves and droughts are also generating more dust and longer summer bushfire seasons. They may also cause more smog; the chemical reactions that cause smog are changing, but it is not clear if there are more, less, faster or different reactions occurring. Although pressures on air quality from industry remain low, some toxic pollutant emissions have increased since 2016, and the trend is deteriorating. Airborne pollen also causes significant health challenges for many sensitive people with asthma and respiratory conditions. Although the pressure on air quality from wood fire heaters and motor vehicles remains high, levels are stable. Light pollution – in particular, artificial light at night – can lead to ecological changes. In marine areas close to our coastal cities, these can include decreased reproductive success in fish, shifts in predatory behaviour of invertebrates and fish, and changes to the physiology and biochemistry of reef-building corals and fish. Coastal regions near major Australian cities are likely to be affected, given the ubiquity of global coastal light pollution. Intertidal and shallow subtidal habitats are among the most affected, as artificial lighting is common along beaches, coastal streets and promenades, and within harbours and marinas. Recreation and tourism Pressures on the environment include disturbances associated with recreation and tourism, hunting, fishing and collecting, which can impact plants and animals on both land and sea in even the most remote areas of Australia. Public parks, conservation reserves and heritage areas provide valuable recreation opportunities, which are important for people’s mental wellbeing and health. But, although Australians enjoy being part of nature, some of our recreational activities can be extremely detrimental to our environment and heritage. Impacts on natural and cultural heritage can occur from direct use and the development of supporting infrastructure, or indirectly – for example, through the introduction of invasive species. The nature of the impact depends on where it occurs and the level of interest: small visitor numbers can potentially have a major impact in sensitive areas such as high-quality conservation areas or wilderness areas; large visitor numbers can have significant effects at any site, especially when this level is not planned for. Coastal tourism and its associated recreational activities have long dominated Australia’s international and domestic tourism market, particularly at beaches and the Great Barrier Reef. Environmental pressures associated with tourism include trampling, pollution, degradation, habitat loss, erosion, disturbance of wildlife, and increased demands on local resources and infrastructure (Sun & Walsh 1998, Canteiro et al. 2018). Since 2016, major changes in tourism patterns have occurred. These were due to the 2019–20 bushfires and heatwaves, which affected many popular coastal destinations, followed by the closure of Australia’s international borders in early 2020 due to the COVID-19 pandemic, and intermittent lockdowns that temporarily restricted local mobility and domestic tourism. Many recreational vessels use coastal waters and harbours, providing an important connection to nature for many Australians (see also Aquaculture and fishing). However, marine vessels can cause environmental damage from anchor dragging, moorings, exhaust, noise pollution, fuel spills and copper pollution from antifouling coatings. They may also carry invasive species in ballast water and on their hulls. Pressure from recreational boating is expected to increase. For example, the number of registered recreational vessels is predicted to increase in areas of population growth, such as New South Wales, where more than 26,000 vessel moorings are currently registered (TfNSW 2015). Wetland ecosystems hold significant ecological, recreational, spiritual, cultural and economic significance. Although the greatest threat to freshwater ecosystems and biodiversity is the modification of water processes that has occurred as a result of water resource development, recreational pressure from fishing and increased human interaction can be part of the overall cumulative impact on species. Disturbances associated with recreation, tourism, hunting, fishing and collecting have had negative impacts on biodiversity in even the most remote areas of Australia. Human activities in Antarctica are intensifying, with increasing numbers of national scientific missions and international tourists until the suspension of cruise ships due to the COVID-19 pandemic in early 2020. Larger numbers of visitors increased pressures on small ice-free areas, as well as risks to fragile ecosystems from waste, pollution (including plastics and oil spills), non-native species and disease vectors.