1498. Extreme Heat in South Asia Made Approximately Three Times More Likely by Climate Change 

On 14 May 2026, World Weather Attribution (WWA) published the results of a rapid attribution study on the extreme heat that affected India and Pakistan from April to May 2026.

During the heatwave, maximum temperatures exceeding 46°C were recorded in several parts of India, exposing hundreds of millions of people to dangerous heat conditions. According to the report, at least 37 heat-related deaths were reported in India, while 10 deaths were recorded in Karachi, Pakistan. The event also triggered record-high electricity demand due to increased cooling needs, while agricultural drought conditions affected more than 1 million km².

Using observational datasets and 19 climate models, WWA concluded that anthropogenic climate change made this 15-day heatwave approximately three times more likely. The analysis also estimated that a heatwave of similar magnitude would have been about 1°C cooler in a pre-industrial climate.

The report states that, under today’s climate conditions, a 15-day heatwave of this scale is now considered roughly a “1-in-5-year event,” meaning there is about a 20% chance of experiencing comparable temperatures in any given April. In contrast, the 2022 South Asian heatwave was considered a rarer event because it occurred earlier in the season and lasted longer.

Importantly, WWA noted that the increase in extreme heat in April is greater than that observed in May. This suggests that dangerous heat seasons in South Asia are beginning earlier and lasting longer. The report also highlights rising risks from “humid heat” associated with high humidity during the pre-monsoon season, in addition to extreme dry heat.

The analysis further found that, over the past decade alone, global mean temperature has increased by approximately 0.4°C, during which the likelihood of similar heatwaves increased by about 35%, while their intensity increased by around 0.3°C.
Looking ahead, the report projects that with an additional 1.3°C of global warming, heatwaves of this magnitude would become more than twice as likely again and approximately 1.2°C hotter. It warns that climate conditions resembling late April 2026 could become a “relatively cool pre-monsoon season” in the future.

At the same time, the report notes that aerosols and expanded irrigation in South Asia may exert localized cooling effects, potentially moderating the overall rise in air temperature compared to some other regions. However, these same factors may also increase relative humidity, making it more difficult for the human body to regulate temperature and thereby amplifying heat stress.

While acknowledging efforts by India and Pakistan to strengthen heat countermeasures through Heat Action Plans (HAPs), the report points out that outdoor workers, low-income populations, and people living in poor-quality housing remain highly vulnerable. It also highlights that heatwaves are often not officially recognized as “disasters,” limiting access to disaster relief funding. In addition, urbanization, declining green cover, urban heat island effects, and worsening air pollution are all identified as compounding heat-related risks across South Asia.

The study reinforces the conclusion that extreme heat in South Asia is not an isolated anomaly, but a phenomenon whose frequency and intensity are increasing due to human-induced climate change.

Contributor: Miyuki IIYAMA, Strategic Coordination Office