ClimateChange – Rising Monsoon Heat Threat May Extend India’s Dangerous Heat Season
ClimateChange – India could face a much longer period of dangerous heat exposure in the coming decades, as rising global temperatures are expected to intensify severe heat stress not only during summer but also throughout the monsoon season, according to a recent scientific study.
Researchers have warned that warming conditions may significantly increase the occurrence of uncompensable heat stress, a situation in which the human body can no longer effectively cool itself because of a combination of excessive heat and humidity. The findings suggest that this growing threat could affect public health, workforce productivity, and overall climate resilience across several densely populated regions of the country.
Study Highlights Growing Monsoon Heat Concerns
The research, published in the journal AGU Advances, examined how heat stress patterns across India have changed over recent decades and how they may evolve under future warming scenarios. Scientists from the Indian Institute of Technology Gandhinagar, along with experts from Stanford University and Purdue University in the United States, contributed to the study.
According to the researchers, the monsoon season, traditionally associated with rainfall and relatively cooler conditions, may increasingly experience dangerous heat-humidity combinations as global temperatures continue to rise. They found that heat stress events during July to October could become far more common under a world that is 2 degrees Celsius warmer than pre-industrial levels.
Sharp Increase Recorded Over Four Decades
The study analyzed data covering the period from 1979 to 2021 and found a notable rise in the frequency and geographical spread of uncompensable heat stress across India.
During the 1980s, such conditions affected less than 0.01 million square kilometres. By 2020, the impacted area had expanded to approximately 0.04 million square kilometres. This trend indicates that dangerous heat conditions are becoming increasingly widespread.
Historically, the highest occurrence of uncompensable heat stress has been observed during the summer months between March and June. During this period, around 8 percent of the country experienced these conditions, while only about 1 percent was affected during the monsoon season.
Future Warming Could Transform Heat Patterns
Researchers project that this balance could change dramatically in the future. Under a warming level of 2 degrees Celsius, nearly similar portions of India may experience uncompensable heat stress during both summer and monsoon months.
The study estimates that about 60 percent of the country could face such conditions during summer, while roughly 53 percent may be affected during the monsoon season. This projected increase is largely linked to rising humidity levels combined with elevated temperatures.
Scientists also estimate that between 800 million and 1.2 billion people could be exposed to uncompensable heat stress under different warming scenarios, highlighting the scale of the challenge facing the country.
Regional Hotspots Identified Across India
The research identified several regions that are especially vulnerable to extreme heat stress. During summer, the Indo-Gangetic Plain and many coastal areas face the highest risk, partly due to elevated temperatures and moisture transported inland from the Bay of Bengal before the onset of the monsoon.
In contrast, monsoon-related heat stress is driven primarily by high humidity levels rather than extremely high temperatures. Researchers observed that these events often occur when air temperatures remain between 35°C and 38°C but humidity levels are exceptionally high.
Punjab and parts of northwestern India have already recorded such conditions during the monsoon season. Experts noted that temporary breaks in monsoon rainfall can create an environment where heat and humidity combine to produce particularly hazardous conditions.
Health and Economic Challenges Ahead
Scientists emphasized that prolonged exposure to uncompensable heat stress can have serious consequences. When the body fails to release accumulated heat, individuals face a higher risk of heat-related illnesses, organ damage, and even death.
The study concludes that northwestern India, the Gangetic Plain, and eastern coastal regions are likely to remain major heat stress hotspots. However, future climate warming may cause monsoon-season heat stress to become more frequent than summer heat stress in some of these regions, creating new challenges for public health planning and adaptation efforts.