Climate profile of South Asia

Global warming is making Earth’s surface hotter day by day. Global temperatures in 2024 were 1.28°C above the 20th-century baseline (1951–1980), overshooting the record set in 2023. ^{Reference Bardan5} It is predicted that in the coming years most cities in South Asia will experience a month of extreme heat every summer, more droughts and more floods in monsoon, increasing mortality and the need for air conditioning. There has been a threefold rise in extreme rainfall events in the past 70 years in the central belt of India. The year 2024 witnessed the hottest summer months, with daytime temperatures reaching 48–49°C accompanied by sultry heat waves in many places across North India, ^{Reference Coleman6} and 2025 faced one of the worst ever floods in many parts of North and Western India, Pakistan and China. ⁷ The possible impact of these recent events on mental health is yet to be assessed.

Air pollution is another serious environmental hazard in South Asia: of the 30 cities in the world with the poorest air quality, 17 are in South Asia. ^{Reference Bardan5} India ranks fourth, after Nepal, Pakistan and Bangladesh, among South Asian countries in the worst air quality index category according to the Environmental Performance Index 2024. ^{Reference Block, Emerson, Esty, de Sherbinin and Wendling8} The air quality index surged to hazardous levels, nearing 450 (‘hazardous’) in many parts of North India in late 2024. The levels of fine particulate matter (PM_2.5) in the air have increased to nearly 100 times the World Health Organization’s safe limit.

Climate change and its effects on mental health in South Asia

South Asia has been highly susceptible to extreme weather events owing to its geographically precarious location. Such events and catastrophes lead to loss of livelihoods, property damage, forced migration and economic loss, along with adverse health consequences. A review covering studies on the subject from South Asia between 2020 and 2024 found the affected population to suffer depression, anxiety, PTSD and increased risk of suicide. ^{Reference Patwary, Bardhan, Haque, Moniruzzaman, Gustavsson and Khan4} Risk of anxiety and depressive disorders, drug and alcohol use, suicide and PTSD increased particularly after an acute climate event.

Temperature rises have also been found to be associated with increased rates of mental health morbidity and mortality, including suicide attempts, mood and anxiety disorders, insomnia, substance misuse, behavioural abnormalities and psychiatric emergencies. A study found that in India, a 1°C rise in temperature during the agricultural growing season increases annual suicides by 0.0008 per 1 00 000 people. India has witnessed around 59 300 farmer suicides due to effects of global warming between 1980 and 2010. ^{Reference Carleton9} The unpredictable rain patterns and failed attempts to sustain livelihoods have forced farmers to migrate away from their homes, increasing the incidence of suicide among them. Furthermore, food shortages and hunger lead to increased risk of infections, malnutrition-related diseases, and neurocognitive and neurodevelopmental disorders. One study found that around 66% of people suffered moderate to severe psychological symptoms after cyclone Amphan in Bangladesh in 2020, and 10.9% reported suicidal ideation. ^{Reference Hossain, Ahmed, Rahman, Sammonds, Zaman and Benzadid10}

Various recent systematic reviews and meta-analyses found that children, pregnant women, elderly people and those with chronic illnesses are especially vulnerable to developing adverse mental health outcomes. A global survey in 2021 reported that 59% of 10 000 children and young adults from 10 countries had eco-anxiety, that is psychological distress due to concern about the consequences of a deteriorating environment or ecological crisis. It is especially important to address this anxiety because of children’s naive coping skills and inability to avoid or mitigate psychosocial stressors. ^{Reference Hickman, Marks, Pihkala, Clayton, Lewandowski and Mayall11} The risk of learning difficulties, negative affect and decreased emotion regulation, temperamental problems, restlessness, bedwetting and aggression increases with climate-related disasters. The World Health Organization estimates that around 88% of climate-related diseases affect children under 5 years of age. ^{Reference Sheffield and Landrigan12}

Rising temperatures and air pollution increase the risk of cognitive impairment or dementia, especially in elderly people. A study found compelling evidence of increased incidence of cognitive deficits and dementia with long-term exposure to pollutants such as carbon monoxide (CO) and nitrogen oxide (NO_x). CO is mainly responsible for the greenhouse effect raising Earth’s temperature. NO_x is produced mainly during combustion of fossil fuels. These gases cause oxidative stress in the central nervous system, leading to cell loss, neuroinflammation and neurodegeneration. ^{Reference Radua, De Prisco, Oliva, Fico, Vieta and Fusar-Poli13} There is rising evidence from India and across the globe highlighting the impact of high PM_2.5 levels on development of various psychiatric and neurodevelopmental disorders through a number of mechanisms, including altering gut flora, neuroinflammation and socioeconomic factors such as access to health resources, green spaces and sports facilities. ^{Reference Sethi, Agarwal, Vora and Gosavi14,Reference Li, Chen, Gu, Chen, Liu and Lei15}

Figure 1 summarises the physical and mental health consequences of various forms of climate change. A causal pathway has been proposed, but the figure should be interpreted in the light of recent evidence by Radua et al. ^{Reference Radua, De Prisco, Oliva, Fico, Vieta and Fusar-Poli13} Although 237 associations have been found and proposed, convincing evidence was found for only one (long-term exposure to solvents and risk of cognitive decline). Other associations with a high level of credibility included exposure to PM₁₀ with post-partum depression, sulfur dioxide (SO₂) with schizophrenia relapse, rising temperature with suicidality, cyclone exposure with PTSD, and CO/NO_x emissions with dementia. Many countries are yet not considering mental health in their response to climate emergency. ^{Reference Radua, De Prisco, Oliva, Fico, Vieta and Fusar-Poli13}

Fig. 1

Environmental and human consequences of global warming.

Suggested solutions

The climate is changing fast and there is a need to act faster. As outlined above, the acute and long-term repercussions of climate change have detrimental effects on mental health. Thus, individuals, families, health professionals, the government and the whole community need to work in unison to combat the climate crisis and prevent the world from having to grapple with the effects of the climate disasters.