Realising opportunities for agricultural, forestry and mining developments requires an understanding of the environmental risks, as well as the economic, social and perhaps even environmental benefits.
Agriculture
Increasing population, personal income and global market demands produce pressure to increase the production yield and profitability from agriculture and grazing industries across Australia (see Agriculture management). This can be achieved by intensifying those systems or increasing the amount of land accessible to those systems (e.g. developing northern Australia: Australian Government 2015, ONA 2018). But agricultural intensification or expansion can be in competition with other uses of the land, reducing natural capital values (e.g. by clearing native vegetation, reducing carbon stores and increasing greenhouse gas emissions) and leading to further declines in biodiversity (Kearney et al. 2019).
As of 30 June 2017, there was 393.8 million hectares (ha) of agricultural land in Australia, making up just over half (51%) of Australia’s total land area (ABS 2018). Of this land, 340.8 million hectares (ha) (or 86.5%) was used for grazing, 66.6 million ha (or 16.9%) was used for cropping or improved pastures, 0.8 million ha was used for forestry, and a further 0.1 million ha was used for other agricultural uses. Queensland had the largest area of grazing lands and Western Australia the largest area of cropping. By 2020, agriculture accounted for 55% of Australian land use, 11% of goods and services exports, 1.9% of gross domestic product (GDP) and 2.6% of employment (ABARES 2021d).
An estimated 57,300 agricultural businesses applied 5 million tonnes of fertiliser to a total of 50 million ha of agricultural land across Australia in 2016–17, with ammonium phosphates being the most widely used (ABS 2018). Of all agricultural businesses, 33% (or 28,800) applied soil enhancers on 5 million ha of land. Limesand and limestone were the most commonly used soil enhancers, used to reduce soil acidity, and accounted for 47% of the total area on which soil enhancers were applied (ABS 2018). The most common land cultivation practice for crops and pasture was zero or minimum till, where no cultivation is done apart from sowing or planting (ABS 2018). The most common crop stubble and trash management practices were retained on-ground (5.8 million ha), retained standing (5.3 million ha) and grazed off (3 million ha) (ABS 2018).
Indigenous involvement in agriculture and grazing, while still relatively small, is growing. This may change in coming years as Indigenous ownerships of land increases. The Indigenous Land and Sea Corporation (ILSC) has been active in the space of agriculture (see case study: Indigenous Land and Sea Corporation). The ILSC National Indigenous Land and Sea Strategy (ILSC 2019b:10) outlines that:
‘to help achieve greater outcomes for Indigenous people and to grow the Indigenous Estate, the ILSC has identified – and is working in – key sectors of the economy that present opportunities for Indigenous Australians or where Indigenous land holders may have a competitive advantage. They include both existing and emerging markets. The expansion of our remit into water opens up new opportunities for Indigenous people in these focus areas. Opportunities we’ve understood from discussions with groups and which through partnerships create new Indigenous benefits’
The value of production based on animals and plants is steadily increasing (PHA 2020), and the industry aims to reach $100 billion by 2030 (NFF 2019a). The greenhouse gas emissions associated with agriculture have been fairly stable over the last decade (DISER 2021c, DISER 2021g, DISER 2021d) (Figure 30), but can fluctuate with stock numbers, and crop type and area. The relatively low emissions in 2019–20 were mainly due to destocking during the 2017−19 drought (Appendix 2 in AHA 2019a).
Forestry
Australia’s forest industries generate native forest and forest plantation timbers, and products for buildings and infrastructure, paper and packaging materials, furniture, and landscaping.
Australia’s native forests are among the richest biomes on Earth. Australia has 134 million hectares (ha) of forest, covering 17% of Australia’s land area (MPIGA & NFISC 2018, Jacobsen et al. 2020a). Queensland has 39% of Australia’s forest, the Northern Territory 18%, Western Australia 16% and New South Wales 15% (ABARES 2019). The forests of eastern Australia, which extend from northern Queensland to southern New South Wales, and forest ecosystems in south-west Western Australia are recognised as global biodiversity hotspots (i.e. they have a very large number of plant species that occur nowhere else and the region has been substantially developed) (Williams et al. 2011, Zachos & Habel 2011) (see the Biodiversity chapter).
Some of this richness is protected: 35% of Australia’s native forest is on land protected for biodiversity conservation or where conservation is a specified management intent (see Protected areas) (MPIGA & NFISC 2018). For example, 26% of Australia’s native forests were included in the National Reserve System as of June 2016. Indigenous people and communities have ownership, management or special rights of access over around 52% of the total Australian forest area, almost all of which is native forest, based on data compiled as of June 2016 (Jacobsen et al. 2020a).
As of 2018, 6.3 million ha of native forests set aside for commercial wood production was on public-owned lands, and 21.8 million ha was leasehold or private native forests (ABARES 2019). Commercial plantations made up 1.94 million ha. The total log volume harvested from native forests was 4.2 million cubic metres, compared with 28.7 million cubic metres harvested from commercial plantations (ABARES 2019). The export value of wood products was $3.6 billion, which was less than imports ($5.6 billion) (ABARES 2019). Forestry and forest product manufacturing industries contributed 0.5% to GDP (ABARES 2019).
Increasing the production yield and profitability of forestry and forest products can be hampered by natural disasters such as bushfires and biosecurity risks such as myrtle rust. These may increase harvest pressure and drive the need to convert more land to plantations and carbon farming in some regions, including on agricultural lands. This can compete with other uses of the land, and reduce or increase other natural capital values (e.g. by reducing the availability and quality of habitat for biodiversity, or increasing habitat quality and availability through authentically biodiverse plantings).
However, changing the use of the land does not necessarily lead to degradation. For forestry in particular, native forestry and commercial plantation forestry need to be considered separately because of trade-offs in highly contested values such as biodiversity retention versus maximised timber production. Increased tree planting for commercial plantations can potentially result in positive local-scale (amenity) and global-scale (carbon capture) outcomes, for the period between harvests. Other opportunities to increase natural capital values and ecosystem services arise through environmental plantings – for example, farm agroforestry and stewardship plantings can help with salinity, erosion, and habitat for biodiversity (see Forestry management). The first systematic, evidence-based assessment of natural capital risks for the Australian forestry sector offers an approach that can account for the sector’s impacts and dependencies on natural capital (Smith et al. 2021).
Extractive industries
Australia claims the world’s most diverse and plentiful mineral and energy reserves, with a relatively unexplored surface and subsurface geology (Figure 31). These reserves include bulk commodities such as thermal and metallurgical coal, natural gas, iron ore, bauxite and uranium, which are complemented by significant reserves of base and precious metals such as nickel, copper, zinc, gold, silver and lead, as well as emerging critical minerals such as lithium and rare earths (DISER 2020a). The location of energy and mineral resources and operating mines have been mapped by Geoscience Australia (e.g. Bernecker 2019, Britt 2020, Hughes 2021).
Australia’s mining industry is the largest economic contributor to Australia’s GDP, contributing more than 10%, or $202 billion, of the Australian economy in 2019–20 (ABS 2020a). Australia offers significant prospects for developers of energy resources (Commonwealth of Australia 2020b) and critical minerals (Commonwealth of Australia 2020a). Over the past 5 years, investment in mineral exploration doubled from $344.7 million in June 2016 to $878.3 million in June 2021. Metres drilled also doubled over the same period, of which around half were for new deposits, with a focus on gold and base metals (ABS 2021d). This shift in mining and exploration to more dispersed areas will inevitably come at the expense of other natural values, which can be addressed through long-term strategic assessment and planning (Sonter et al. 2018).
Land classified as ‘mining and waste’ makes up less than 1% of Australia’s land surface (ABARES 2021a, ABS 2021e). Between 2010–11 and 2015–16, land committed to mining increased by around 115,000 hectares (an addition of 9.4%), and land formerly committed to mining reduced by 45,000 hectares (or 3.7%); the net result was a 5.7% increase in land committed to this use (Figure 27). However, the impacts on that land are immense, including on Indigenous heritage and cultural values (see the Indigenous and Heritage chapters). An extensive network of townships, transport corridors, pipelines and other services support mining areas, but further fragment the landscape. Prospecting for new deposits is also a significant contributor to land degradation if the tracks, drilling sites and spoils are not rehabilitated. Emissions associated with mining are increasing (DISER 2021d, DISER 2021g, DISER 2021c) (Figure 30).
Much of Australia’s mining occurs on land with significant Indigenous management and native title; for instance, more than 80% of the mineral value extracted in the Northern Territory comes from Indigenous-owned land (NLC 2021). As of June 2020, around 188,000 people were directly employed in the mining sector, including exploration and related services (ABS 2021c). Indigenous employment in the mining sector, while still very low, has increased almost 5-fold over 15 years to 6,649 in 2016 (ABS 2017a, Parmenter & Barnes 2021). Tailored employment pathways and opportunities negotiated under Indigenous land-use agreements have contributed to this increase (MCA 2020, Parmenter & Barnes 2021).
Compared with agriculture, forestry and fishing, which consumed approximately 58% of Australia’s water resources, the minerals industry was responsible for only 3.7% of Australia’s water consumption in 2015–16 (down from 3.9% in 2014–15) (MCA 2018). The industry often uses water not suitable for other purposes, such as saline and hypersaline water (MCA 2018) (see the Inland water chapter).
Despite the economic benefits of our mineral wealth, Australia continues to bear the legacy of tens of thousands of orphaned or abandoned mine sites that pose an ongoing risk to the environment, public health and safety (Campbell et al. 2017). Some of these sites are under active management or have been rehabilitated (Figure 32). This cumulative footprint of the past and present legacy of hard rock mining in Australia is substantial and not well understood (Werner et al. 2020). The Cooperative Research Centre for Transformations in Mining Economies is addressing some of the complex challenges underpinning current mine closure and relinquishment (CRC TiME 2021), but many other issues of legacy responsibilities are still to be addressed (Roche & Judd 2016).
Land clearing
Clearing of native vegetation is a major cause of habitat loss and fragmentation, and has been implicated in the listing of 60% of Australia’s threatened species in the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act) (Kearney et al. 2019) (see the Biodiversity chapter). Land clearing can also lead to processes that degrade soils, such as erosion, salinisation, loss of organic matter and depleted fertility (see Soil). Native vegetation clearing in Australia is driven mainly by expansion of land dedicated to agriculture and, to a lesser extent, forestry and infrastructure, including urban development (see the Urban chapter). In New South Wales, Heagney et al. (2021) found that farmers make decisions to clear land in response to economic opportunities presented by favourable commodity market signals. Land clearing is also a significant contributor to greenhouse gas emissions and, conversely, land can absorb emissions through vegetation regrowth (see Carbon) (see the Climate chapter).
Following primary clearing, and depending on the intensity of land management, woody vegetation can regrow and may be recleared in future years before it is finally committed to the changed land use. Therefore, mechanical clearing events years apart can be partial, and sometimes in the same general location, or reinforced using fire and stock grazing to suppress woody vegetation regrowth (see Carbon above the ground in vegetation biomass). Figure 33 shows where primary forest has been converted to alternative land uses since 1990 (DISER 2021f).
Over the 5-year period from 2015 to 2019, nearly 58,000 hectares (ha) of primary forest was cleared annually, and a further 359,000 ha of secondary forest (regrowth after previous clearing) was recleared on average each year (Figure 34; Table 6). This represents a 15% reduction in the amount of primary clearing, and virtually no change in the amount of reclearing, compared with the previous 5 years (LULUCF Tables 1a, 1b in DISER 2021a). A small proportion can be attributed to non-native vegetation clearing for plantation forestry or agricultural purposes, or removal of invasive non-native woody species (see Invasive species management).
Over the same 5-year period, the cumulative area of sustained forest regrowth (i.e. not recleared in the prior year) was 736,500 ha, which is 36% less than in 2010–14; in other words, more sustained regrowth was recleared over 2015–19 than previously (LULUCF Table 6 in DISER 2021a). Extensive areas of sparse woody vegetation losses were also recorded between 2015 and 2019, averaging 2.27 million ha per year, a loss rate 8% greater than the previous 5 years (Figure 35; Table 6). While gains in sparse woody vegetation (averaging 2.35 million ha per year between 2015 and 2019) were greater than losses, these gains were 14% less than the previous 5 years. These woody vegetation gains and losses are influenced by the combined pressures of climate and land-use change, and cyclical water availability in semi-arid regions (Liao et al. 2020).
Since 1990, more than 6.1 million ha of primary forest has been cleared – some of which is subject to reclearing after regrowth (sometimes repeatedly) (DISER 2021a). The total area of sustained regrowth as of 2019 was 4.13 million ha (LULUCF Table 6 in DISER 2021a). 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. For example, Ward et al. (2019) found that 7.7 million ha of potential habitats for terrestrial threatened species were cleared or substantially degraded between 2000 and 2017 (Figure 37). 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 provides quality wildlife habitat (see Vegetation condition).
The larger jurisdictions with extensive areas of woody vegetation (New South Wales, the Northern Territory, Queensland, Western Australia) dominate the pattern of vegetation loss or gain (Figure 36). In the 5 years from 2015 to 2019, extensive areas of primary forest or regrowth forest were cleared from Queensland (64% and 70% of the national total, respectively) and New South Wales (20% and 16% of the national total, respectively) (Table 6). While the rate of primary forest clearing is now substantially less than the baseline of more than 400,000 ha cleared each year between 1990 and 1994, there has been little change in the rate of forest regrowth clearing, which instead shows a slight increase. In New South Wales over the past 5 years, there has been a steady increase in clearing and reclearing for agricultural purposes; substantial areas (as much as 70% between 2017 and 2019) are yet to be associated with an authorisation (see case study: Woody vegetation loss in New South Wales). The majority of forest clearing in Queensland is also attributed to agriculture, such as conversion to pasture for stock grazing in the Brigalow Belt and Mulga Lands bioregions (Queensland Government 2021b). Using national forest and woodland loss data (DoEE 2019a) and accounting for the impact of natural events, 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 (Figure 37).
From 2015 to 2019, Queensland dominated loss of sparse woody vegetation (31% of the national total), followed by the Northern Territory (28%) and Western Australia (26%) (Table 6). Compared with the 1990–94 baseline, there has been a significant increase in the extent of sparse woody vegetation regrowth, though the gains between 2015 and 2019 were less than the previous 5-year period (Table 6) (see Carbon above the ground in vegetation biomass). In addition to impacts from clearing, net changes in shrub or sparse woody vegetation appear to be strongly correlated with the El Niño Southern Oscillation Index (Bastos et al. 2018, Malhi et al. 2018), which has a significant influence on rainfall patterns across Australia (see the Climate chapter). In some wet–dry tropical regions, fire also affects vegetation. For example, 55% of all lost sparse woody vegetation in the Northern Territory was found to coincide with a fire event (DISER 2021d). Fire can result from planned burns for land management purposes or unplanned bushfires that may be part of a natural disturbance regime to which many ecosystems have adapted.
Landfill and land contamination
Australia creates and imports many goods that unfortunately end up as waste (see the Urban chapter). Other countries increasingly will not accept our waste, yet landfill and other waste strategies have unacceptable impacts on our land through soil and land pollution. Littered and illegally dumped waste also has a significant impact on the land through its direct effect on soils, biota and habitats, and by facilitating the spread of diseases and pest species.
Burying waste has been a common means of disposal. The volume of buried waste has not changed significantly over the past 10 years, though there is some variability between states (Figure 42a). While waste going to landfill in Western Australia in 2018–19 was 42% lower than in 2006–07, there have been increases in New South Wales and Queensland of 10% and 17%, respectively (Pickin et al. 2020). In 2018–2019 alone, 113 million tonnes of waste nationally was managed using landfill, with the volume of hazardous waste almost doubling since 2006–07 (Figure 42b). There are estimated to be 600 registered landfill sites and potentially as many as 2,000 unregulated facilities (Figure 43). Many landfills have high environmental protection standards, incorporating features such as composite or geomembrane containment liners, landfill gas capture and combustion, and planning for long-term land rehabilitation (Infrastructure Australia 2019). However, many smaller regional landfills often do not meet these standards (Infrastructure Australia 2019).
Waste in landfill can be a source of soil contamination and leakage into waterways, and can be an ignition risk and cause of bushfires under certain climatic conditions (e.g. end-of-life tyres). In 2018–19, around 24% of the mass of end-of-life tyres was buried, mostly at mine sites and other remote locations, adding to the at least 10 million tonnes of tyres already buried or landfilled nationally (Pickin et al. 2020). The use of land for waste and its consequent contamination can also permanently remove that land from production or urban uses, or require costly remediation.
In 2017–18, Australia generated around 7.5 million tonnes of hazardous waste, around 11% of all waste generated (67 million tonnes) in this period. This is a 34% increase on hazardous waste generated in 2014–15 (5.6 million tonnes) (Pickin et al. 2018, Latimer 2019, Pickin et al. 2020).
The more than 70 hazardous waste types include contaminated soils and asbestos from development and demolition projects, as well as wastes from the chemicals, heavy manufacturing and mining industries.
A range of wastes with hazardous characteristics arise from everyday sources, for example:
- tyres, oils, oily waters and lead acid batteries from motor vehicles
- grease trap waste from commercial cooking
- leaded glass from used TVs and computers.
Contaminated soils make up 35% of hazardous waste (Latimer 2019). Most of this soil waste was sent to landfill (57%). Another 19% was recycled, 10% underwent specific treatment (to reduce or remove the hazard), and 10% was stored for accumulation and later release into management infrastructure (Latimer 2019).
The amount of hazardous wastes increased strongly in the 8 years to 2017–18, increasing at a compound annual growth rate of approximately 9% per year since 2013–14, when all jurisdictions began supplying equivalent data (Latimer 2019). Contaminated soils and asbestos waste have driven this trend, with nationally unprecedented increases in 2017–18 (Latimer 2019). The amount of contaminated soils has increased beyond the recent historical range (Latimer 2019).
Like the coal-seam gas industry of the last decade, new industries are leading to the emergence of new wastes, and new chemicals are emerging as contaminants within wastes or due to increased regulatory understanding of chemical hazards (Latimer 2019). The most pressing of these are PFAS (per- and poly-fluoroalkyl substances) (see the Inland water chapter). Historical use of PFAS in firefighting foams in Australia has resulted in increased levels being detected at sites like airports, defence bases, and other sites where firefighting training has been conducted, or where fire suppression systems are installed for extinguishing liquid-fuel fires (Australian Government 2021). Increased environmental levels of PFAS have also been found near some industrial areas, effluent outfalls and landfill sites (Australian Government 2021). Outside these areas, it is unlikely that increased levels of PFAS would be present in the local environment. PFAS are highly mobile in water, can travel long distances from their source point, do not fully break down naturally in the environment and are toxic (COAG 2019, COAG 2020). Investigation and management of PFAS contamination require a nationally coordinated approach (HEPA 2020).
The effects of contaminants on Indigenous people include impacts on water (through heavy metals) and major changes to river systems. For example, studies have demonstrated that mine waste contamination in the McArthur River, which altered the entire nature of the river system and its function in providing food, water and lifestyle, heavily impacted the population of Borroloola in the Northern Territory (DITT 2021, Higgins et al. 2021).