SAN FRANCISCO, July 31 (Xinhua) -- Estimates in a study published Monday indicate that climate change has led to failing harvests that push farmers into poverty and cause more than 59,000 suicides in India over the last 30 years.
University of California, Berkeley, researcher Tamma Carleton discovered that warming a single day by 1 degree Celsius, or 1.8 degrees Fahrenheit, during India's agricultural growing season leads to roughly 65 suicides across the country, whenever that day's temperature is above 20 degrees Celsius, or 68 degrees Fahrenheit. Warming a day by 5 degrees Celsius has five times that effect.
Published in the Proceedings of the National Academy of Sciences (PNAS), the study helps explain India's evolving suicide epidemic, where suicide rates have nearly doubled since 1980 and claim more than 130,000 lives each year.
While high temperatures and low rainfall during the growing season impact annual suicide rates, similar events have no effect on suicide rates during the off-season, when few crops are grown, implicating agriculture as the critical link.
Finding that 7 percent of this upward trend can be attributed to warming that has been linked to human activity, Carleton acknowledged that "it was both shocking and heartbreaking to see that thousands of people face such bleak conditions that they are driven to harm themselves."
More than 75 percent of the world's suicides are believed to occur in developing countries, according to a UC Berkeley news release, with one-fifth of those in India alone.
Using methods that she developed in a previous paper published in the journal Science, Carleton, a doctoral fellow at UC Berkeley's Global Policy Laboratory and a Ph.D. candidate in agriculture and resource economics, projected that today's suicide rate will only rise as temperatures continue to warm. "Without interventions that help families adapt to a warmer climate, it's likely we will see a rising number of lives lost to suicide as climate change worsens in India."
More than half of India's working population is employed in rain-dependent agriculture, long known to be sensitive to climate fluctuations such as unpredictable monsoon rains, scorching heat waves, and drought. Heat drives crop loss, which can cause ripple effects throughout the Indian economy as poor harvests drive up food prices, shrink agricultural jobs and draw on household savings. During these times, it appears that a staggering number of people, often male heads of household, turn to suicide.
Carleton tested the links between climate change, crop yields and suicide by pairing the numbers for India's reported suicides between 1967 and 2013, using a dataset prepared by the Indian National Crime Records Bureau, along with statistics on India's crop yields, and climate data. To isolate the types of climate shocks that damage crops, she focused on temperature and rainfall during June through September, a critical period for crop productivity that is based on the average arrival and departure dates of India's summer monsoon.
She cautioned that her estimates of temperature-linked suicides are probably too low, because deaths in general are underreported in India and because national law held that attempted suicide was a criminal offense until 2014, further discouraging reporting.
In response to rising suicide rate, the Indian government has established a crop insurance plan equivalent to 1.3 billion U.S. dollars.
Advocating protecting rural workers from major economic shortfalls in time of warming, forecast to reach 3 degrees Celsius by 2050, through policies like crop insurance or improvements in rural credit markets, Carleton warned that "without interventions that help families adapt to a warmer climate, it's likely we will see a rising number of lives lost to suicide as climate change worsens in India."