April 2025 India & Pakistan heatwave mostly strengthened by human-driven climate change

Contact Authors

•  Gianmarco Mengaldo, NUS, Singapore 📨 mpegim@nus.edu.sg 🗣️English, Italian

• Chen Chen, CCRS, Singapore, 📨 chen_chen@nea.gov.sg 🗣️English, Mandarin

• Valerio Lucarini, Leicester University 📨v.lucarini@leicester.ac.uk 🗣️Italian, English

• Davide Faranda, IPSL-CNRS, France  📨 davide.faranda@lsce.ipsl.fr 🗣️English, French, Italian 

Citation

• Mengaldo, G., Chen, C., Lucarini, V., & Faranda, D. (2025). April 2025 India & Pakistan heatwave mostly strengthened by human-driven climate change. ClimaMeter, Institut Pierre Simon Laplace, CNRS. https://doi.org/10.5281/zenodo.15240277

Press Summary

• Meteorological conditions leading to the April 2025 India and Pakistan heatwave are up to 4°C warmer in the present than they were in the past.

• This event is associated with very exceptional meteorological conditions. 

• We mostly ascribe the increased heat to human-driven climate change, with natural climate variability likely playing a limited role.

Event Description

In mid-April 2025, a severe heatwave struck both India and Pakistan, pushing temperatures to dangerous levels and intensifying the challenges faced by millions. From April 14 to 15, parts of Pakistan, particularly Balochistan, saw temperatures soar to up to 49°C (120°F). This unusual early arrival of the heatwave caught many off guard, with local residents experiencing power outages lasting up to 16 hours, exacerbating the impact of the extreme heat. In India, the capital city of New Delhi reported temperatures surpassing 40°C (104°F) on multiple occasions, up to 5°C above the seasonal average. The heatwave spread across neighboring states like Rajasthan, where laborers and farmers struggled to work in the scorching conditions, with increasing reports of heat-related illnesses.

The heatwave in both countries is disproportionately impacting vulnerable sectors of the population and is  severely testing overall human limits, pushing the thresholds for survivability. In addition to the direct impacts on health, including enhanced risks to pregnant women and children, the heat posed significant threats to agriculture and food security. With crops unable to withstand the early heat and farmers facing water shortages, the agricultural sector was hit hard, further jeopardizing livelihoods. The extreme temperatures also led to an increased demand for electricity, worsening power shortages and disrupting daily life. The reliance on groundwater to partially counter the effects of the heatwave is impacting negatively the aquifers of the region. The heatwave's consequences extended beyond human health, impacting essential services, education, and food production, with experts warning of the growing vulnerability of both countries to such climate extremes in the future.

The meteorological conditions were characterized by an unusual pattern of Surface Pressure Anomalies, with scattered negative pressure anomalies over Pakistan and positive pressure anomalies over the Himalayan mountain range. Temperature anomalies reached up to +12°C across Afghanistan, Pakistan, and India. Precipitation data indicate dry conditions in the area affected by the heat, and Windspeed Data show calm conditions. 

Climate and Data Background for the Analysis

The occurrence of large positive anomalies of temperature and extremely dry conditions in the pre monsoonal season is becoming commonplace in South Asia, as shown by the persistent and spatially extended events in 2015, 2019, 2022 and 2024, which have led to thousands of deaths and disruption to ecosystems and society, with temperature records being shattered every few years. The IPCC AR6 report provides a clear relationship between heatwaves and climate change in South Asia. Climate change is significantly contributing to the increase in heatwaves in India through various mechanisms: Warming resulting from climate change has led to an increased frequency, intensity, and duration of heat-related events, including heatwaves, in most land regions, with high confidence (IPCC SR OC C6 - Page 27). Climate change is projected to alter land conditions, affecting temperature and rainfall in regions, which can enhance winter warming due to decreased snow cover and albedo in boreal regions, while reducing warming during the growing season in tropical areas with increased rainfall. Global warming and urbanization can enhance warming in cities and their surroundings, especially during heatwaves, with a higher impact on night-time temperatures than daytime temperatures (IPCC AR6 WGII FR - Page 1058). Observed surface air temperature has been increasing since the 20th century in Asia, intensifying the threat of heatwaves across the region. In South Asia specifically, the frequency and duration of heatwaves have increased, associated with Indian Ocean basin-wide warming and frequent El Ninos, leading to severe impacts on agriculture and human discomfort. The combination of global warming and population growth in already-warm cities in regions like India is a major driver for increased heat exposure, with urban heat islands elevating temperatures within cities relative to their surroundings. Indeed, South Asia is considered to be one of the regions most impacted in the future by the climate crisis.

Our analysis approach rests on looking for weather situations similar to those of the event of interest having been observed in the past. For this event we have low confidence in the robustness of our approach given the available climate data, as the event is very exceptional in the database

ClimaMeter Analysis 

We analyze here (see Methodology for more details)  how events similar to the meteorological conditions leading to the April 2025 India & Pakistan heat wave have changed in the present (1987–2023) compared to what they would have looked like if they had occurred in the past (1950–1986) in the region [55°E 80°E 20°N 40°N]. The surface pressure over Pakistan shows not much change, with a slight decrease of up to 2 hPa. Temperature changes show conditions that are up to +4°C warmer in the present compared to the past. Precipitation changes show no significant differences. Wind speed changes indicate slightly windier conditions, with an increase of +4 km/h, or up to +10%.

Similar past events suggest that the meteorological patterns associated with the heatwave occur with a similar frequency now as they did in the past. Changes in urban areas reveal that New Delhi, Jaipur, and Islamabad are experiencing warmer conditions, with Islamabad being the most affected, seeing temperatures up to +3°C higher than in the past.

Finally, we find that sources of natural climate variability, notably the El Nino—Southern Oscillation, may have influenced the event. However, since the current phase is ENSO-neutral, the observed changes in the event, compared to the past, are likely due to human-driven climate change, with only a minor contribution from natural variability. 

Conclusion

Based on the above, we conclude that meteorological conditions similar to the April 2025 India & Pakistan heatwave have become  up to 4°C warmer than in the present than in the past .  We interpret the April 2025 India and Pakistan heatwave  as an event driven by very exceptional meteorological conditions whose characteristics can mostly be ascribed to human driven climate change.