Metros may see highest rise in heat related mortality: Study

Increases in heat-related mortality will overshadow declines in cold-related mortality

Under a worst case scenario in the long run, urban areas of Delhi, Ahmedabad, Bangalore, Mumbai and Kolkata are projected to experience the highest absolute increases in the heat related mortality by 2080s, says a study by the Indian Institute of Management, Ahmedabad (IIM-A).

Titled 'Predicted Increases in Heat related Mortality under Climate Change in Urban India', the working paper considers air temperature projections for two representative concentration pathways (RCP) of 4.5 and 8.5 for its projections, wherein the latter represents are worst case scenario. Jointly authored by Hem H. Dholakia, Vimal Mishra, and Amit Garg of IIM-A, the paper also states that increases in the heat related mortality will overshadow declines in the cold related mortality (winter season).

"From a policy perspective, the five urban areas that will experience the highest increases in the future heat related mortality after accounting for population increase are Delhi (15200 deaths), Ahmedabad (17600 deaths), Bangalore (14900 deaths), Kolkata (19400 deaths) and Mumbai (15300 deaths). Of these, Ahmedabad is the only urban area that has recently instituted a heat-health warning system (AMC 2013) thereby underscoring the need to institute planned adaptation measures for other urban areas," the paper states.

For its research, the paper considered air temperature projections for the two (4.5 and 8.5) representative concentration pathways (RCP). The paper provides a comprehensive assessment of mortality in 52 urban areas with a population of more than one million that are located in diverse climactic regimes in India.

"The RCP 4.5 assumes a scenario where radiative forcing stabilizes at 4.5 W/m2 by the year 2100. This corresponds to an increase in average global temperature of about three degrees centigrade. The RCP 8.5, on the other hand, is an extreme (or worst case) scenario where very little mitigation actions are taken by countries to thwart future climate change. This corresponds to a scenario which has the highest greenhouse gas emissions and may lead to an increase in average temperatures up to six degrees centigrade," it further states.

Mortality is projected to increase 71 per cent and 140 per cent in the late 21st century under the RCP 4.5 and 8.5 scenarios, respectively.

Highlighting the need of urgent measures, the paper calls for policy intervention as an early precaution.

"This is the first attempt to show that urban India is projected to experience high mortality from the future warming. Our findings underscore the need for Indian policy makers to anticipate, plan and respond to the challenge of climate change. The heat action plan of Ahmedabad (AMC 2013) as well as the state level action plans on climate change (MoEF 2014) are indicative of initial forays being made on this front. However, a greater emphasis on public health, policy coordination across sectors along with health system strengthening is needed in urban India to address current and future climate change related health challenges," the paper concludes.