Lucknow faces rising humid heat, heat-related deaths may hit 4,000 annually by 2050

Lucknow faces rising humid heat, heat-related deaths may hit 4,000 annually by 2050

Lucknow is witnessing a growing number of days when high temperatures combine with high humidity to create severe heat stress, with experts warning that the trend could significantly increase health risks in the Uttar Pradesh capital.

Lucknow faces rising humid heat, heat-related deaths may hit 4,000 annually by 2050

A report published in the journal Nature has projected that, under high-emission scenarios, heat-related excess deaths in Lucknow could rise by around 50 per cent by 2050, potentially resulting in about 4,000 heat-related deaths annually when the city's projected urban expansion is taken into account.

Former India Meteorological Department (IMD) director general K J Ramesh said global warming was increasing not only temperatures but also moisture levels, particularly across the Indo-Gangetic plains.

"Lucknow is situated in the middle of the Indo-Gangetic plains. Its low elevation and basin-like geographical setting allow moisture to remain trapped when air circulation is weak. High humidity intensifies the impact of heat and increases health risks, particularly respiratory and heat-related illnesses," he said.

An analysis by think tank Climate Trends found that Lucknow recorded 289 days of heat and severe humidity between 2015 and 2024, with maximum temperatures of at least 35 degrees Celsius and humidity of 60 per cent or more.

The number of such days increased from 123 during 2015-19 to 166 during 2020-24. Lucknow recorded the highest number in 2020, with 45 days of intense heat and humidity.

The analysis attributed the trend to rising moisture levels linked to climate change, as well as the city's rapid and largely unplanned expansion, which intensifies local temperatures through the urban heat island effect.

Senior environmental scientist Seema Javed said high humidity reduces the body's ability to cool itself through sweating, increasing the risk of heat stroke even when temperatures are lower than during extremely hot days.

"People need to understand that summers are no longer what they used to be," Javed said, calling for changes in government policies governing working conditions for labourers and workers as well as broader social measures to protect people from humid heat.

The analysis also found a persistent rise in hot nights. Lucknow recorded 126 such nights in 2024, compared with 124 in 2015 and 128 in 2016. Even in 2018, the number stood at 93.

Abhiyan Tiwari, head of climate resilience and health at NRDC India, said the 35 per cent increase in hot and humid days between 2015-19 and 2020-24 was particularly concerning.

High humidity prevents sweat from evaporating, reducing the body's natural cooling, while warmer nights make it harder for the body to recover from daytime heat, he said.

The report said humid heat was also affecting labour productivity, with around 20 per cent of annual working hours exposed to unsafe heat-stress conditions when Wet Bulb Globe Temperature (WBGT) crosses 30 degrees Celsius.

Under higher-emission scenarios, this share could rise to 30-40 per cent, resulting in substantial productivity losses and billions of dollars in annual economic damage, it said.