Coastal dists facing humid heatwave threat: Study

Thiruvananthapuram: Kerala's coastal districts are facing a growing threat from humid heatwaves during breaks in the summer monsoon, a new study has found, warning of serious health risks and the need for advance preparedness. The research, led by scientists at the University of Reading in the UK and published in Climate Dynamics, points to a rising pattern in which coastal regions experience intense heat stress not just from temperature but from a dangerous combination of heat and high humidity. Unlike conventional heatwaves, these humid events are driven by elevated moisture levels in the air, which prevent the body from cooling effectively. Scientists caution that such conditions can trigger rapid overheating, cardiovascular strain and even heatstroke within hours, even when temperatures do not appear extreme."Kerala's coastal districts are more prone to humid heatwaves during the summer monsoon compared to inland areas. The risk increases significantly during monsoon break phases," said Dr Akshay Deoras, lead author of the study. The study uses wet-bulb temperature a measure that combines heat and humidity to assess the severity of these events. Higher wet-bulb temperatures indicate conditions where sweating becomes ineffective, sharply increasing the risk to human health. Researchers say the findings carry significant implications for disaster preparedness. The study shows that such humid heatwave conditions can be forecast up to four weeks in advance, providing a critical window for authorities to respond. This lead time could help in mobilising healthcare resources, opening cooling centres, adjusting school timings and ensuring adequate power supply during peak demand periods, the study suggests. The analysis draws on 84 years of atmospheric data from 1940 to 2023, including the ERA5 global reanalysis dataset and rainfall records from the India meteorological department. Researchers examined 261 active monsoon phases and 188 break periods to track changes in humid heatwave risk. The study was carried out in collaboration with the University of Leeds, the UK Met Office and the Indian Institute of Tropical Meteorology.