Rising temperatures could increase the burden of mental and behavioral disorders (MBD) by nearly 50% by 2050, presenting a significant challenge to Australia’s healthcare system.
Mental and behavioral disorders represent a major public health issue in Australia, accounting for 15% of the total disease burden in 2024, up from 12% in 2003. This reflects a 31% increase in age-standardized incidence over two decades. Nearly half of Australians aged 16 to 85 will experience MBD at some point in their lives. With ongoing climate warming, this burden is expected to rise further.
Epidemiological studies have confirmed a clear link between higher temperatures and adverse mental health outcomes. For every 1°C increase above a region’s optimal temperature, deaths related to mental health rise by 2.2%, and incidence rates increase by 0.9%. Possible mechanisms include sleep disturbances, dehydration, elevated stress hormones, and increased social isolation during hot weather — all factors that may worsen anxiety, depression, substance abuse, and psychosis. Vulnerable groups, such as the elderly, those living alone, and people with existing health conditions, face particular risks.
As the driest inhabited continent, Australia is especially susceptible to global warming. By quantifying the impact of heat on the country’s MBD burden, researchers can identify regions at highest risk and better allocate resources and support. Such insights are crucial for targeted public health interventions and enhancing climate adaptation strategies — especially for the most vulnerable communities.
The Study
This latest research provides the first comprehensive assessment of the global and Australian burden of MBD attributable to heat exposure. Using data from the Australian Burden of Disease Study (ABDS) by the Australian Institute of Health and Welfare, high temperature was defined as days exceeding a local threshold known as the Theoretical Minimum Risk Exposure Distribution (TMRED).
The analysis covered all Australian states, territories, and secondary statistical areas. Using state-level estimates of MBD burden, researchers calculated the heat-related portion for each area to understand where communities are most affected. Future projections were made for the 2030s and 2050s under different climate and adaptation scenarios.
During the baseline period of 2003–2018, heat accounted for 1.8% of Australia’s total MBD burden. South Australia bore the highest burden, with 2.9% of MBD (62.6 disability-adjusted life years [DALYs] per 100,000 people) attributed to heat. The Northern Territory had the highest average threshold temperature and the greatest relative risk of MBD. In Victoria, 2.2% of MBD (51.1 DALYs per 100,000) was linked to heat. Vulnerability is influenced not only by climate but also by socioeconomic status, population structure, and healthcare accessibility.
Looking ahead, under a high-emission climate scenario (RCP8.5) and without adaptation to rising temperatures, the attributable MBD burden could more than double by the 2050s. Population growth (65.4%) and increased heat exposure (34.6%) are expected to jointly drive this increase.
While future burden projections inherently carry uncertainty and the model may not fully capture all real-world factors (such as socioeconomic conditions, living alone, or compounding extreme climate events), this study remains one of the first to forecast future heat-related MBD burden incorporating climate, demographics, and adaptation scenarios. These findings provide timely evidence to inform mental health and climate adaptation planning nationally and internationally.
Implications and Next Steps for Practitioners
With climate warming, the burden of mental and behavioral disorders is projected to increase nearly 50% by 2050 due to rising temperatures and population growth. Practitioners need to recognize heat as a legitimate risk factor for mental health. During hot weather, vulnerable patients require monitoring and practical advice on hydration and cooling strategies. At a systemic level, governments should implement integrated, forward-looking policies that combine public health with broader urban, social, and environmental planning, embedding mental health considerations into climate adaptation efforts.
We urge the development and implementation of locally tailored heat health action plans. These should strengthen healthcare preparedness to support vulnerable groups during heat events and integrate mental health services into emergency responses. Special attention is needed for high-risk populations in remote heat-prone areas, where health burdens and access challenges are greater.
This research supports proactive shifts in climate and public health policies. Its insights can guide strategies that anticipate future risks rather than merely react to current trends, incorporating climate-related mental health risks 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, especially in low- and middle-income countries, is critical to ensure global preparedness. Investments in climate mental health research, public education, and cross-sector collaboration will be essential to reduce the long-term impacts of climate change on mental health.
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