2013 Environment and Health - Basel
Mapping environmental heat stress variables in relation to climate change: examples from India
Background:The impact of heat stress on the health and productivity of the work force is substantial, particularly in tropical countries such as India where the current climate already puts workers at their physiological limit. Negative health impacts in the form of heat stroke and work capacity reductions are commonly reported in local Indian occupational health studies. Climate change modeling shows that global temperatures will increase in the future. Mapping of spatial and monthly heat exposures distributions now and in the future can provide important input into environmental and occupational health protection programs. Aim: The aim of this study was to determine the current and future impacts of heat stress on Indian populations using Wet Bulb Globe Temperature (WBGT) distributions maps.
Methods: Grid cell based data on current and future modeled climate variables from CRU (Climate Research Unit, University of East Anglia) were used to calculate WBGT and create maps of WBGT distributions in India for different months and years. Results: WBGT distribution maps indicate that in 2005, average afternoon WBGT levels (indoors or in full shade) were above 26 oC for the majority of India, with values up to 33-34 oC in some places. By comparison, 2050 maps indicate average afternoon WBGT levels above 28 oC for large parts of India, with values up to 35 oC possible in some places.
Conclusions: Current heat exposure levels in India are already higher than occupational heat guidelines recommend for worker health and productivity. Tropical and sub-tropical countries, such as India, with large working populations are particularly susceptible to the negative impacts of climate change. Mapping heat exposure based on climate modeling outputs can be a useful tool for national and local health programs, as such maps can indicate where heat stroke risk is likely to increase.