Drought and hotter temperature impacts on suicide: Evidence from the Murray-Darling Basin

The Murray-Darling Basin (MDB) is Australia’s prime agricultural region, where drought and hotter weather pose a significant threat to both rural residents’ income and mental health – hence increasing their potential suicide risk. The suicide rate in remote Australia has been shown previously to be almost double that of major cities. This study is the first to examine the relationship between suicide and increased temperature and drought severity within the MDB, using a monthly database from 2006-2016. This time-period encompasses the main period of the Millennium drought (from 2001/02-2009/10). Poisson fixed-effects regressions with robust standard errors were used to model total suicide rates at an SA2 area level, followed by a series of subsample analyses by age and gender. The results suggest that drought as well as higher temperatures increased total MDB suicide rates, while a higher proportion of the population working in agriculture was also associated with increased suicide rates. The type of drought was also found to be important. The higher the duration and severity of the drought (i.e. extreme droughts), the higher the total suicide rate, driven largely by suicide rates among MDB males aged under 50. However, suicide risk in females aged under 50 also contributed to total suicides in the MDB, and females were vulnerable to extreme droughts. Higher maximum monthly temperatures in the MDB impacted more on male suicide than female, which is consistent with other findings, such as higher temperatures affecting Australian boys’ mental health more than girls. Reasons for the greater impact of temperature on male suicide risk compared to females may include genetic biological factors; greater male interaction/exposure to the outside environment; or farming masculinity issues. More research on gender-specific mental health and environmental influences will be needed to clarify the exact relationship. Although people aged 10-29 in the MDB had the lowest overall suicide rate by age group during 2006-2016, they were the most vulnerable in the face of extreme drought. This study provides several insights for suicide prevention. In the rural sector especially, coordinated and integrated policies are necessary to reduce the negative consequences of drought. Such policies will include both macroeconomic climate change and drought farming policy, but also mental health, natural resource management and agricultural policy, and rural economic and social development policies. There may be an urgent need for developing and funding further mental health services, specifically targeting younger people, in rural areas affected by drought. Future research needs to better understand the links between various gender and age risk factors of suicide in drought-affected communities in order to build capacity and resilience.