Human-driven climate change made May hotter

Bengaluru: As 37 cities in India recorded temperatures above 45º Celsius, scientists said the heatwave was made worse by 1.5º Celsius due to climate change caused by humans.

Scientists at ClimaMeter, a research project funded by the European Union and the French National Centre for Scientific Research (CNRS), used historical data and analysis of surface temperature in the region comprising India and southern Pakistan for the study. The analysis took into consideration what the May month's heatwave incident of present time (2001-2023) would have looked like had it occurred in the past (1979-2001).

Both human-driven climate change and natural climate variability played a role during last month's heatwave. However, while the surface pressure changes did not show any difference for the event's intensity in the past or present time, the analysis of temperature showed a significant change.

"The temperature changes show that similar events produce temperatures in the present climate change at least 1.5º Celsius warmer than what they would have been in the past (1979-2001) over a large area of the region analysed," the study said.

The study also considered the changes taking place in urban areas. "Changes in urban areas reveal that New Delhi, Jalandhar and Larkana area more than 1º Celsius warmer in the present compared to the past," it said, adding that the results were adjusted with the readings from the India Meteorological Department, after removing the wrong reading of 53º Celsius.

"We interpret India's May heatwave as a largely unique event whose characteristics can mostly be ascribed to human-driven climate change," the scientists said.

David Faranda of French CNRS said in a note that the findings show that the unbearable level of heat was driven by fossil fuel burning.

"There are no technological solutions for adapting Indian Metropoles for temperatures approaching 50º C. We should all act now to reduce CO2 emissions and avoid exceeding vital temperature thresholds in large areas of the subtropics," he added.

Gianmarco Mengaldo, National University of Singapore, said the study shows the complex interplay between natural variability and climate change, "with the latter playing an important role in critical synoptic-weather-pattern changes in tropical and subtropical regions" that may significantly aggravate heatwaves in the near future.