Long dry spells this monsoon in some parts of India meant warmer days and nights even in July. Climate change is making the world hotter and more humid, and the number of dangerous humid heat days is rising, a new study shows. Sixteen Indian cities saw dangerous humid days for more than six months each year, the study found.

‘Felt temperature’ or ‘wet bulb temperature’ is the thermal discomfort the human body feels and is a combination of maximum temperature and relative humidity. Researchers at Climate Central defined dangerous humid heat days as days when the maximum wet-bulb temperature is 25°C or higher. In simple terms, it could mean a daytime maximum temperature of around 26°C and humidity levels around 20 percent or a variation of the same (use this calculator).

Humid heat inhibits the body’s ability to cool down through its natural mechanism of sweating. Across India, humidity has increased at the rate of 0.79 percent per decade between 1969 and 2012. High humidity levels coinciding with high temperatures are likely to create lethal weather conditions and affect the lives of millions across the Indian subcontinent. Climate change will make such conditions more frequent as the 21st century comes to a close.

While India is not among the worst-affected countries, the study shows several Indian cities where dangerous humid heat days attributable to climate change have multiplied in about 55 years. Overall, 59 Indian cities were included in the study, of which only two—Bengaluru and Srinagar—did not see any days with dangerous humid heat.

Tirunelveli, Chennai, Tiruchirapalli and Vijayawada saw more than 250 days (or eight months) of dangerous humid heat a year in the past decade. Tirunelveli ranks 34th and Chennai ranks 39th in the list of 961 cities analysed across the globe.

Among the worst affected countries in Asia are Brunei Darussalam (also worst affected in the world), Singapore, Malaysia and Cambodia, while India ranks 16th in Asia. The country had, on average, 141 days of dangerous humid heat during 2016-2025, of which 49 days or 35 percent were attributable to climate change.

The study calculated the number of observed days with dangerous humid heat, and used a counterfactual analysis to estimate the number that would have occurred without the influence of climate change.

ISignal reached out to the Union health and environment ministries, and the National Disaster Management Authority on how they plan to adapt to climate-driven humid heat, what health protocols will be put in place for vulnerable groups, how the departments will plan for occupational protections and adaptation funding for most impacted Indian cities. We will update this report when we receive a response.

Southern and central Indian cities worst off

Our survival depends on our bodies........

© newslaundry