BENGALURU: Global climate change is the greatest and foremost environmental challenge of the 21st century. That it also has an adverse impact on mental health has been established in a recently published report by the Nature Mental Health Earth-Brain-Health (EBH) Commission (EBHC). ‘Nature’ is the world’s leading multidisciplinary science journal.
The Commission report, while stating that environmental changes “alter the conditions in which people develop, live and age, and with them the conditions for brain and mental health”, also draws the world’s attention to its “uneven” impact on “low and middle-income countries (LMICs), small island developing states (SIDS), children, older adults, people with disabilities and marginalized communities, who carry higher exposure with fewer resources for recovery and are least represented in the evidence base”.
The report explains how environmental conditions reach mental health through “interacting biological pathways, including neuro inflammation, endocrine and circadian disruption, and epigenetic processes; psychological pathways, including stress, loss of control and agency, and disrupted meaning and place; and social pathways, including inequality, displacement, isolation and institutional distrust. Effects are time-dependent, with sensitive developmental windows in which exposure carries disproportionate and only partly reversible consequences”, the EBHC report explains.
“Heat and heatwaves, air and noise pollution, extreme weather and compound events, urbanization, and the loss of green and blue spaces are associated with depression, anxiety, cognitive decline, and impaired emotional and behavioral functioning, although evidence strength and causal clarity differ across exposures, populations and settings. Evidence is most developed for heat, air pollution, noise and urban stressors, and remains heterogeneous for biodiversity loss and digital environments,” the report states.
These exposures “rarely occur singly: heat, pollution, poor housing, deprivation and limited access to care frequently co-occur, and their combined effects may be nonlinear and cannot be recovered from single-exposure studies”.
The EBHC observes that the principal obstacles to action (against climate change) are “organizational and financial rather than evidential. Cohorts, Earth-observation systems, federated analytic methods and environmental governance instruments already exist but are maintained separately”, states the report.
The Commission’s recommendations pursue three goals. First, to shift from reactive treatment towards anticipatory, life-course prevention, by integrating environmental and mental health science, care and policy, and by identifying risk during the developmental windows in which intervention is most effective. Second, to make brain and mental health an objective of environmental, urban and climate policy rather than an unmeasured consequence of it, through well-being indicators embedded in impact assessment, adaptation planning and sustainability reporting, and through environments designed for it.
Third, to change how exposure, voice and progress are distributed, by prioritizing the regions and groups carrying the greatest burden, establishing communities as co-designers of interventions rather than consultees, and assessing national progress by measures that value mental well-being alongside economic output.
The Commission has also suggested a “transparent, bias-audited and trustworthy governance of data and artificial intelligence (AI), and a dedicated international funding and coordination architecture, including an Earth, Brain, Health research fund and a global observatory, with specific provision for participation by LMICs”.
Dr Vivek Benegal, senior professor of Psychiatry, former head of department, Psychiatry, National Institute of Mental Health & Neuro Sciences (Nimhans) and one of the EBH commissioners, said Nimhans has been looking at how climate change events impact the human brain. In 2023, a study led by Nimhans and King’s College, London, had found that even low exposure to arsenic, far below the thresholds set by the WHO can “alter” brain structures and impair cognitive abilities in children, adolescents and young adults, making them more vulnerable to serious mental illnesses.
