Climate Change and Mental Health: A Systematic Scoping Review

Background and Purpose: Established science demonstrates that human activity has increased the concentration of greenhouse gases in the atmosphere, creating unprecedented shifts in the global climate and resulting in observable changes to our planet. A continued lack of progress in reducing global emissions means continual and growing threats to human lives, as demonstrated by a growing body of literature considering impacts of climate change on public health. While the effects of climate change on mental health are an integral part within the overall climate-related public health impact, the current field is described as ‘neglected’ and ‘under-researched’. A systematic scoping review was therefore conducted to examine the current state of the literature and to explore patterns and characteristics to inform future research and practice.

Methods: To capture as many relevant papers as possible, 1937 search terms were created for ‘mental health’ and 55 for ‘climate change’. 8 databases were used with no restrictions for date. To be included in the study, climate change had to be explicit, meaning the article situates at least part of its background or contribution in the global climate change field. Only empirical studies in English were included for this review and studies were excluded if there is no scientific consensus linking human activity and increased frequency or severity of weather event (i.e. earthquakes). 8,568 were retrieved and screened for title/abstract and 974 full-text articles were reviewed. 13 additional studies were added from handsearching and other systematic reviews.

Results: A total of 94 articles were included in this review. 65 studies used quantitative approaches, with 20 using qualitative and 9 using mixed method approaches. Only 12 studies explicitly reported a theoretical framework that guided their methodological approach. The majority of quantitative studies tested associations between weather events and mental health outcomes, with only 4 testing for indirect effects. Studies took place in 30 countries, with most occurring in Australia (n=26), Canada (n=11), the United States (n=11), China (n=6), and the United Kingdom (n=6). 17% of studies took place in low-to-middle-income countries (LMICs) with only two taking place in Africa and none in South America. 55 studies empirically linked the weather event to climate change’s impact in the region’s local context. The remaining 39 only linked the weather event to a broad climate change context, mostly within the introduction or discussion sections. Common study populations included mental health patients (n=18), indigenous groups (n=17), and farmers (n=12).

Conclusions: Despite a broad search strategy, a main finding of this review is the dearth in empirical research, particularly on populations and regions that will be impacted most by climate change. The existing studies demonstrate a relationship between climate change-related events and mental health outcomes, however better understanding of indirect impacts and the mechanisms within these connections are needed. Future studies should also incorporate accurate and context-relevant climate change data and be guided by established theoretical frameworks. In addition, future research should consider the concurrent impacts climate change will have on health, the built environment, and changes in ecosystem and animal health.