New research examines climate change-induced heat and suicide risk in Australia

New research led by Curtin University has found that about 0.5%, or around 260, of suicides in Australia over a two-decade period were linked to unusually high temperatures due to climate change.

The increased risk was observed in men aged 55 and older, particularly during the warmer months. The work is published in the diary BMJ Mental Health.

Lead researcher Dr Lucas Hertzog, from Curtin’s World Health Organization Collaborating Centre for Climate Change and Health Impact Assessment, said the findings suggest public health strategies may be needed to address the mental health impacts of climate change if the results are replicated in other studies.

“When we compare the differences in data from 2000 to 2019 with the previous five decades, we find that older Australian men are at greater risk of suicide during extreme heat anomalies associated with climate change,” Dr Hertzog said.

“Our research shows that heat anomalies during the study period were 0.02°C to 2.2°C warmer than in the historical period across Australia.

“Specifically, approximately 0.5% of the 50,733 suicides during this period were related to these heat disorders.

“Future studies should investigate whether and how global warming affects mental health and suicide, especially given the widespread effects of climate change on both nature and human society.”

Lead author Dr Ivan Hanigan, director of Curtin’s World Health Organization Collaborating Centre for Health Impact Assessment, said the research underscores the urgent need for climate mitigation and adaptation strategies in government planning.

“This includes putting in place support systems and services to help people cope with extreme heat, which is becoming more frequent and intense due to global warming,” said Dr. Hanigan.

“This study is designed as a population-level analysis and does not address individual variables such as socioeconomic status, personal mental health history, access to services, or the contexts of each individual. Therefore, this study does not definitively demonstrate that temperature excursions cause an increase in suicide rates.”

“Our findings highlight the importance of considering environmental factors in addition to individual-level factors in public health strategies and suicide prevention measures.”