Study links 59,000 suicides to climate change in India
A University of California study has linked 59,000 suicides to the effects of climate change in India over the course of three decades. The research found a correlation between difficult periods of high temperatures and low rainfall during crop growing season and increased rates of suicide, with rates being more severe in the southern region of India. A single day’s increase in temperature by one degree Celsius leads to approximately 65 suicides across India, according to the report. The Indian government has launched a $1.3bn climate-based crop insurance scheme to tackle suicide rates, but the study found that evidence to support the scheme was “lacking”.
Warming due to climate change has triggered over 59,000 farm-related suicides in the past three decades, a study has revealed that shows high temperatures and low rainfall during growing season substantially impact annual suicide rates. The study also finds the southern region of India tends to have the most severe increase in suicide for a given change in temperature.

“These are deaths that would not have occurred, had the warming we’ve observed in the historical climate record not taken place,” University of California, Berkeley, researcher and author of the study, Tamma Carleton, told The Indian Express in an email interview. “Suicide is a heartbreaking indicator of human hardship, and I felt that if this phenomenon were in fact affected by a changing climate, it would be essential to quantify its effect and consider this relationship as we build climate policy for the future.”

Although the Indian Government’s recently announced a $1.3 billion climate-based crop insurance scheme motivated as suicide prevention policy, the study states that “evidence to support such an intervention is lacking.” However, Carleton acknowledges that given the limited availability of data, the study cannot directly speak to particular policy solutions that are actively being debated in India.

The study ‘Crop-damaging temperatures increase suicide rates in India’ published in the Proceedings of the National Academy of Sciences (PNAS) on July 31 showed that “warming a single day by 1 degree Celsius during India’s agricultural growing season leads to roughly 65 suicides across the country, whenever that day’s temperature is above 20 degrees Celsius.” Further, warming a day by 5 degrees Celsius has five times that effect. The study relies on data from the National Crime Records Bureau (NCRB), “which contains the universe of reported suicides in the country from 1967 to 2013.” Carleton said that data used in the study from the NCRB does “not differentiate between farmers and other occupations” since the occupation of suicide victims was not listed until very recent years.

“There were not sufficient data with this occupational information to conduct my analysis. Therefore, I use all suicide records going back to 1967 to estimate the impacts of the climate,” she said. “If in fact farmers and agricultural workers are more affected by the climate than other occupations, my estimates would be a lower bound on the true effect that is applicable to these vulnerable populations.”

Carleton pointed out that the southern states of India “tend to be hotter on average, and also tends to have a higher average suicide rate in all years.” The study states that Maharashtra, Karnataka, Tamil Nadu and Andhra Pradesh, three of which are in southern India, “not only have severe suicide responses to temperature, but also exhibit large negative impacts of temperature on yield.”

“I show in my analysis that in these locations, crop yields also tend to experience the largest damages for a given increase in temperature,” Carleton said. “These findings suggest that where crop yields are most vulnerable to temperature increases, suicides also respond more strongly to those same temperatures,” she said.

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While optimists often suggest that societies will adapt to warming, Carleton’s research has found no evidence to suggest communities acclimatize to high temperatures, or become more resilient as they get richer. “There are many possible impediments to adaptation that keep communities from being able to reduce the impacts of temperature as the climate warms,” Carleton told The Indian Express, adding existing evidence from other locations where researchers study a range of other types of climate impacts suggests a variety of reasons: high costs of adaptation, poor incentives to adapt, limited access to credit for financing adaptations, difficulty in planning for future risks, incorrect or limited information about the benefits of adaptation, weak government institutions, and poor access to technologies might play substantial roles.

“In the Indian context, many of these barriers to adaptation could be at play, and I hope that future research will help uncover effective means of enabling effective adaptive strategies,” she said. The study indicates that “heat drives crop loss” and predicts a “ripple effect throughout the Indian economy.”

Carleton said that rising incomes realized through economic growth are often thought to enable populations to reduce the negative effects of climate. “Households with more economic resources may be able to invest in heat-tolerant seeds, pay the up front costs of irrigation technologies, or take up crop insurance, while poorer households may be unable to adopt such adaptive strategies,” she said.

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“I tested the hypothesis that as India’s national income rose, the sensitivity of suicides to temperature fell. Likewise, increases in average crop yields could have weakened the link between temperature and suicide by providing agricultural households with more savings and hence more resilience in light of an adverse climate event,” Carleton told The Indian Express. “However, I found that these forms of adaptation were not taking place, as the effect of temperature on suicide is virtually identical in recent years as it was over 40 years ago.”