Climate signals associated with the El Niño-Southern Oscillation (ENSO) could help anticipate the risk of extreme humid heat in India up to six months in advance, a study1 says.
Such early estimates can help protect workers and reduce potential productivity losses, says lead researcher Subodh Kumar Saha at the Indian Institute of Tropical Meteorology (IITM) in Pune.
The findings come amid warnings by the Climate Impact Lab at the University of Chicago that the ongoing ‘super’ El Niño could cause an estimated 239,000 additional deaths globally, and 15,800 in India, from extreme hot days between September 2026 and February 2027.
The IITM researchers say ENSO is the main predictor of year to year variability humid-heat potential occupational productivity loss (hPOPL), measured in labour time lost because workers must slow down, take frequent rest breaks, or stop working altogether to prevent health hazards.
The study combined historical (from 1950 to 2020) climate and population data with two heat-stress metrics, Humidex and wet-bulb globe temperature (WBGT). Statistical analysis of ocean temperatures in the tropical Indo-Pacific could explain about 43% of the global variation and 42% in India. They could predict summer labour productivity losses in India up to six months in advance by looking at the ocean temperatures.
“The six-month predictability period is extremely important. There are very few things in the Earth system where we have this level of confidence,” said Dann Mitchell, a professor of climate science at the University of Bristol. Mitchell said the WHO could amplify health-messaging around El Niño2 with this evidence as many countries lack robust advance warning data.