Heatwave in May warmer than before, worsened by climate change, says report

The researchers assessed past and present weather conditions such as atmospheric pressure at the surface, temperature and precipitation.

They compared low pressure systems — associated with inclement weather such as cyclonic storms — at the end of the 20th century (1979-2001) and in recent decades (2002-2023), when the effects of climate change have become more evident.

The scientists found that heatwaves, such as those that hit India, are now almost 1.5° C more intense.

Temperatures in parts of Delhi such as Najafgarh, Mungeshpur and Narela were in the range of 47-49° C while even central and leafier parts such as Safdarjung recorded temperatures as high as 46° C.

Gianmarco Mengaldo of National University of Singapore, one of the authors of the analysis, said the findings show a complex interplay between natural variations and climate change, with the latter playing an important role in weather-pattern changes in tropical and subtropical regions “that may significantly aggravate heatwaves in the near future”.

The assessment of surface atmospheric pressure anomalies revealed that a significant cyclonic anomaly — a weather pattern that sees warm and moist air moving towards the coast — prevailed over Northwest India and Southern Pakistan.

The analysis also showed that temperatures were unusually higher, by up to 5° C, in some parts of Northwest India and southern parts of Pakistan, coupled with low to moderate winds.

“Based on the above, we conclude that heatwaves similar to the India May heatwave are 1.5° C warmer than the warmest heatwaves previously observed in the country. We interpret India May heatwave as a largely unique event whose characteristics can mostly be ascribed to human driven climate change,” the analysis stated.