Intense heatwaves sweeping across India and Pakistan in April 2025 were as much as 4°C warmer than those experienced during the second half of the 20th century, according to a new international scientific analysis.
The study by ClimaMeter, a consortium of international scientists and climate organisations, shows that the meteorological conditions behind this year's April heatwave have shifted significantly when compared to similar events from the past (1950–1986) to the present (1987–2023). As a result, present-day heatwaves are up to 4°C hotter.
The analysis found that human-induced climate change was the primary driver of these intensified conditions. ClimaMeter, funded by the European Union and the French National Centre for Scientific Research (CNRS), aims to interpret and contextualise extreme weather events in light of climate change by comparing them with historical data.
“The spring heatwave gripping India and Pakistan underscores an alarming intensification of climate extremes, profoundly affecting millions throughout the region,” said Gianmarco Mengaldo of NUS Singapore, a ClimaMeter contributor.
“Rising cases of heat-related illnesses, widespread disruptions to agricultural productivity, and critical water shortages are among the direct consequences of these extreme events,” he added.
In mid-April, the heatwave pushed temperatures to dangerous levels, severely testing human endurance and disproportionately impacting vulnerable communities. On April 14 and 15, parts of Pakistan, especially Balochistan, recorded temperatures as high as 49°C. The unusually early onset of the heatwave caught many residents unprepared, with electricity outages lasting up to 16 hours, worsening the situation.
Similarly, in India, New Delhi saw temperatures exceeding 40°C on multiple occasions—up to 5°C above the seasonal average. The scorching heat extended to neighbouring states such as Rajasthan, where farmers and labourers struggled to work outdoors. Reports of heat-related illnesses have been rising steadily.
The extreme heat has also disrupted essential services, impacted school schedules, and strained food production systems. Experts have expressed concern about the increasing vulnerability of the region to such climatic extremes in the coming years.
While the frequency of heatwaves may appear similar to the past, there are notable differences. Urban centres like New Delhi, Jaipur and Islamabad are experiencing warmer conditions than before, with Islamabad recording temperatures up to 3°C higher than historic levels.
The study also considered natural climatic influences, such as the El Niño–Southern Oscillation (ENSO), but concluded that the current ENSO-neutral phase indicates a minimal natural contribution. Most of the observed warming is attributed to human-driven climate change.
"Burning fossil fuels drives temperatures in India and Pakistan heatwaves to extremes, making them unlivable and directly affecting the entire population. If we don’t act now to reduce CO2 emissions, highly populated areas in the tropics will become uninhabitable, and millions of lives will be at risk," said Davide Faranda of IPSL-CNRS, France.
Scientists continue to stress that the only viable solution is to urgently cut down fossil fuel usage and reduce carbon emissions to mitigate further climate-induced disasters.