Five urban areas that are projected to experience the highest increases in heat-related mortality after accounting for the population increase are Mumbai (15,300 deaths), Delhi (15,200 deaths), Ahmedabad (17,600 deaths), Bangalore (14,900 deaths) and Kolkata (19,400 deaths), says a study by the IIM Ahmedabad.
“India and other developing countries are at higher risk due to high population and low preparedness. Our understanding of changes in heat waves and its implications on human mortality in the projected future climate in urban India is largely limited. To address this gap, we provide a comprehensive assessment of mortality based on 52 urban areas (population greater than 1 million) located in the diverse climactic regimes across India, using downscaled and bias corrected temperature projections,” says the paper titled ‘Predicted Increases In Heat Related Mortality Under Climate Change In Urban India’.
“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 policymakers to anticipate, plan and respond to the challenge of climate change,” it adds.
Data on daily weather variables were collected from the India Meteorological Department (IMD). The team collected data on daily totals of registered deaths from the municipal corporations of Ahmedabad, Mumbai, Bangalore, Hyderabad, Lucknow and Shimla for the period of 2005-2012. Further, heat-related mortality was estimated for the summer season (March to July) and cold-related mortality was estimated for the winter season (November to February). Based on temperature-mortality relationships, deaths for the period 2000-2009 were estimated. “The team used two emission scenarios – representative concentration pathway (RCP) 4.5 and RCP 8.5 to capture a large range of future temperature transitions, from current temperature trajectory to an extreme degree of global warming, thereby addressing a vast range of uncertainty with respect to future climate,” it says.
Results reveal that urban areas in India are projected to witness two-fold or more increases in heat-related mortality, that is summer season, under the projected future climate. 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. Moreover, the findings show that increases in the heat-related mortality will overshadow declines in the cold related mortality. “Results highlight that urban areas are projected to experience more warming in the winter season than that in the summer. Moreover, urban areas located in the northern India, especially in the Gangetic Plain region, are projected to face significant warming in the summer and winter seasons,” the paper says.
The authors further say that the real mortality impact of the projected climate in urban areas in India is likely to be significantly higher than that analyzed in this study. “The 52 urban areas we studied represent about 13 per cent of the Indian population. The remaining population that resides in smaller towns, cities, and rural areas, are also vulnerable to mortality impacts of climate change. The towns and smaller cities of today will burgeon into urban areas with million-plus populations in future as a consequence of urbanisation. Therefore, the health impacts may be higher than what we have estimated. The strength of our study is that they are significant enough to warrant the attention of policymakers,” it says.