Addressing climate change is critical to Australia’s future water supply. Mitigation efforts that limit global warming would reduce drought severity, slow evaporation losses, and improve water reliability for agriculture and communities.
Australia is one of the driest inhabited continents on Earth, and water scarcity has long shaped its economy, communities, and politics. Over the past 30 years, climate change, population growth, and environmental degradation have materially altered the country’s water balance, placing increasing strain on supplies for both food and agriculture and personal drinking and hygiene.
Changes in Australia’s Water Supply Over the Last 30 Years
Since the mid-1990s, Australia has experienced long-term drying trends in the south and east, where most agricultural production and population are concentrated. The Bureau of Meteorology and CSIRO have documented a marked decline in cool-season rainfall since the late 20th century, particularly in autumn and early winter, which has reduced runoff into rivers, reservoirs, and dams despite occasional wet years. [soe.dcceew.gov.au]
The Millennium Drought (2001–2010) represented a turning point. It exposed structural vulnerabilities in Australia’s reliance on rainfall-dependent systems and led to widespread water restrictions, agricultural losses, and ecological decline. While subsequent La Niña periods (notably 2020–22) temporarily replenished storage, the State of the Environment 2021 report found that surface water and groundwater conditions have continued to deteriorate overall due to climate pressures, heat, and increased evaporation. [soe.dcceew.gov.au]
Rising temperatures have further intensified water stress. Australia has warmed by more than 1°C since 1910, increasing atmospheric evaporative demand and reducing the amount of rainfall that translates into usable water for rivers, soils, and crops. This means that even when rainfall totals appear close to average, water availability may still be significantly lower than historical norms.
Water Supply Needs
(a) Food and Agriculture
Agriculture is Australia’s largest water user. According to the Australian Bureau of Statistics Water Account (2023–24), agriculture, forestry, and fishing consumed 11,760 gigalitres (GL) of water, around two-thirds of national water consumption, primarily for irrigation. [abs.gov.au]
Water is critical for irrigated cropping (including cotton, rice, and horticulture), livestock pasture, and food processing. Much of this production depends on river systems within the Murray–Darling Basin, which supplies roughly 40% of Australia’s agricultural output. However, long-term declines in inflows and repeated droughts have reduced water reliability, forcing farmers to adjust crop choices, reduce production, or exit irrigation altogether. [soe.dcceew.gov.au]
(b) Personal Drinking and Hygiene
Households used 1,868 GL of water in 2023–24, primarily for drinking, cooking, sanitation, and hygiene. While per-capita water use has declined over time due to efficiency measures, total urban water demand continues to rise as Australia’s population grows and cities densify. [abs.gov.au]
Infrastructure Australia projects that household water demand will increase by around 10% by the early 2030s, placing further pressure on urban water systems already exposed to climate variability.
Sources of Australia’s Water Supply
Australia relies on a diversified but increasingly stressed mix of water sources:
- Surface water (rivers, dams, and reservoirs) remains the dominant source nationwide but is highly sensitive to rainfall decline and variability. [infrastruc…lia.gov.au]
- Groundwater has become more heavily used during drought periods, particularly in regional and agricultural areas, raising concerns about long-term aquifer sustainability. [soe.dcceew.gov.au]
- Desalination plants now provide climate-independent water supplies in major cities, including Perth, Sydney, Melbourne, Adelaide, and the Gold Coast, playing a central role during drought conditions. [watermeetsmoney.com]
- Recycled water and stormwater, used for agriculture, industry, public spaces, and groundwater replenishment, have expanded since the 2000s as part of drought-resilience strategies. [committee.iso.org]
Pressures on Water Supply
Australia’s water systems are under sustained pressure from multiple sources:
- Climate change is driving higher temperatures, reduced runoff, longer droughts, and more intense heatwaves. [theaustral…farmer.com]
- Population growth, particularly in coastal capital cities, is increasing demand for secure urban supplies. [infrastruc…lia.gov.au]
- Environmental degradation, including bushfires and land clearing, can damage catchments and degrade water quality following heavy rainfall events. [soe.dcceew.gov.au]
- Competing water demands between agriculture, communities, industry, and ecosystems, most visibly in the Murray-Darling Basin, where allocation disputes remain unresolved. [soe.dcceew.gov.au]
Conservation Measures and Future Water Security
Australia has taken significant steps to conserve water and expand supply resilience:
- National reforms under the National Water Initiative and the updated National Water Agreement (2025) aim to balance economic use with environmental and cultural needs. [dcceew.gov.au]
- Major investment in desalination infrastructure has reduced urban reliance on rainfall-dependent supplies, particularly in Western Australia. [watermeetsmoney.com]
- Water recycling has expanded through national guidelines and state action plans, such as NSW’s Recycled Water Roadmap (2025), which support agricultural, industrial, and indirect potable reuse.
- Long-term declines in per-capita household water use reflect conservation pricing, appliance standards, and public behavior change, though climate impacts increasingly offset these gains. [soe.dcceew.gov.au]
Climate Action and Water Security
Addressing climate change is critical to Australia’s future water supply. Mitigation efforts that limit global warming would reduce drought severity, slow evaporation losses, and improve water reliability for agriculture and communities.
At the same time, adaptation, through diversified water sources, advanced forecasting, and resilient infrastructure, will remain essential even under optimistic emissions pathways.
Water, once treated primarily as an infrastructure challenge in Australia, is now widely recognized as a climate issue, central to food security, public health, ecosystems, and long-term economic stability.
This Post was submitted by Climate Scorecard Australia Country Manager, Jessica Gregory.