Impact of climate change induced heat stress on the people working in the coastal cities of India

Indian coastal cities are more vulnerable to heat stress in the context of climate change, with associated physiological stress in the working environment. The increase in heat stress obtained from the Steadman Heat Stress Index (SHSI) and its associated decline in work performance (DWP) are reported in this study using: (a) the reanalysis data sets of the Indian Monsoon Data Assimilation and Analysis (IMDAA) for the period 1981-2020; and (b) the high resolution, bias-corrected simulations of the Indian Institute of Tropical Meteorology (IITM)-Earth System Model (ESM) (source: NEX GDDP) for the period 1981-2014 (historical) and 2015-2050 (Shared Socioeconomic Pathway (SSP) 2.4.5 & 5.8.5) for the coastal cities of India. The SHSI values equivalent to the Wet Bulb Globe Temperature (WBGT), which recommend different rest/work ratios for all the study locations, have been estimated using the model data sets. The results show that the rising heat stress is mainly dependent on the changes in relative humidity in the cities of the west coast, while it is dependent on temperature changes in the cities of the east coast. The cities of Chennai, Nellore, Puducherry and Kochi showed a higher decline in work performance in the SSP2.4.5 scenario, while Mangalore and Thiruvananthapuram were added in the SSP5.8.5 scenario during the decade of 2041-2050. People working without thermal neutralities in Chennai, Nellore, Puducherry, and Kochi were recommended a further 25% increase of rest per hour in the light, medium, heavy, and very heavy work conditions in the future climate scenarios of 2021-2050.