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Rising temperatures could increase the burden of mental and behavioural disorders by nearly 50% by 2050, challenging Australia’s health care system.
Mental and behavioural disorders (MBDs) are a major public health concern in Australia, contributing to 15% of the total disease burden in 2024, up from 12% in 2003, reflecting a 31% increase in age-standardised rates over two decades. Nearly half of Australians aged 16–85 years will experience an MBD at some point in their lifetime. As the climate warms, this burden is expected to grow.
Epidemiological studies have established clear associations between rising temperatures and adverse mental health outcomes. For every 1°C rise above a region’s optimal temperature, mental health-related deaths rise by 2.2% and illness by 0.9%. The underlying mechanisms may include disrupted sleep, dehydration, elevated stress hormones and increased social isolation during heat events, all of which can aggravate conditions like anxiety, depression, substance use and psychotic disorders. These effects are particularly concerning for vulnerable populations such as the elderly, people living alone, and those with pre-existing health conditions.
As the driest inhabited continent, Australia is highly vulnerable to the impacts of global warming. By calculating the extent to which high temperatures affect MBDs across the country, we can better identify where people are at risk and how to help. Such insights can inform targeted public health interventions, optimise resource allocation, and enhance climate resilience — especially for regions and communities most at risk.
Our research
Our latest research provides the first comprehensive estimate of the burden of MBDs attributable to high temperature exposure both in Australia and globally. We defined high temperature as the number of days per year exceeding a locally determined counterfactual threshold, referred to as the theoretical minimum risk exposure distribution (TMRED), in accordance with the Australian Institute of Health and Welfare’s Australian Burden of Disease study (ABDS).
Our analysis spanned all states, territories and small Statistical Area Level 2 regions in Australia. We used state level estimates of MBD burden to calculate the burden in each region based on the population. We then estimated how much of the burden from mental health conditions could be linked to high temperatures in each area. This helped us understand which communities are most affected by heat. We then projected how this burden might change in the future — looking ahead to the 2030s and 2050s — under different climate and adaptation scenarios.
We found that during the baseline period (2003–2018), high temperatures contributed to 1.8% of the total MBD burden in Australia. South Australia had the highest burden: 2.9% of MBDs (62.6 disability-adjusted life years [DALYs] per 100 000 population) were attributable to heat. The Northern Territory had the highest average threshold temperature and the highest relative risk of MBDs. In Victoria, 2.2% of MBDs (51.1 DALYs per 100 000) were attributable to heat. Vulnerability is shaped by more than climate alone; however, factors like socio-economic status, demographics and access to health care also shape vulnerability.
Looking ahead, under a high emissions climate change scenario (RCP8.5), the attributable MBD burden could more than double by the 2050s, if we do not adapt to higher temperatures. This rise would be driven by both population growth (65.4%) and increasing exposure to high temperatures (34.6%).
Predicting future disease burden always comes with some uncertainty, and our models rely on assumptions that may not capture every real-life detail (socio-economic factors, solitary lifestyle, or compounding effects with other climate extremes). Nevertheless, this is one of the first global efforts to forecast future MBD burdens due to heat, taking into consideration climate, demographics and adaptation scenarios. These findings provide timely evidence to inform both national and international efforts in climate-resilient mental health planning.
What can practitioners do (implications and next steps)?
As the climate warms, the burden of MBDs is projected to increase by nearly 50% by 2050 due to both rising temperatures and growing populations. For practitioners, there is a need to recognise high temperature as a legitimate mental health risk factor. During heat events, at-risk patients need to be monitored and offered practical advice on hydration and cooling strategies. At the systems level, governments should adopt integrated, forward-thinking policies that align public health strategies with broader urban, social and environmental planning, and embed mental health considerations into climate adaptation.
We call for the development and implementation of heat-health action plans tailored to local conditions. These should include enhancing health care system readiness to support vulnerable populations during heat events, and integrating mental health services into emergency planning. Special attention should be given to high risk communities in hotter, more remote regions where both the health burden and the challenges of access to care are elevated.
This study offers evidence to support a proactive shift in policy and public health responses to climate change. Its insights can guide strategies that anticipate future risk rather than merely react to current trends, with climate-related mental health risks incorporated into heat-health frameworks and funding decisions.
Globally, Australia can serve as a model for integrating heat-related mental health considerations into climate resilience planning. Further research is needed, particularly in low- and middle-income countries, to ensure global preparedness. Investment in climate-mental health research, public education and cross-sectoral collaboration is vital to reduce the long term impacts of climate change on mental health.
Dr Jingwen Liu is a postdoctoral researcher in the School of Public Health at The University of Adelaide.
Dr Blesson Varghese is a visiting research fellow in the School of Public Health at The University of Adelaide.
Dr Alana Hansen is a senior research associate in the School of Public Health at The University of Adelaide.
Prof Peng Bi is a professor of public health and environmental medicine at The University of Adelaide, a director of the Natural Hazard Research Australia Building Resilience to Impacts of Heatwaves in Australia Consortium (2025-27), and a fellow of the academy of Social Sciences in Australia.
The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.
The statements or opinions expressed in this article reflect the views of the authors and do not necessarily represent the official policy of the AMA, the MJA or InSight+ unless so stated.
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