Black carbon aerosols worsened India’s deadly 2015 heatwave

Black carbon aerosols intensified India’s deadly 2015 heatwave, raising both daytime temperatures and humidity-driven heat stress, according to a new study published in Communications Earth & Environment. Using recent observations and chemistry-coupled regional climate model simulations, researchers found that aerosols present during the heatwave period increased daily temperature maxima by 0.2 to 1.5 degrees Celsius, averaged spatially over the heatwave-affected region.

The study, led by Dewashish Tiwari and colleagues including Chandra Venkataraman, examined how aerosols interact with large-scale climatic drivers that are already known to amplify heatwave temperatures. The authors note that aerosols produce complex regional temperature responses depending on their composition, with black carbon in particular elevating the intensity of the 2015 event.

The effects extended beyond temperature alone. Aerosol-induced dynamic changes in moisture transport increased surface humidity, activating a moist heat stress episode during the event. Daily wet-bulb temperature maxima rose by 0.25 to 1.8 degrees Celsius as a result, combining elevated heat with higher humidity to worsen conditions for people in the affected areas.

Overall, the aerosol effects additionally exposed about 30 million people and 0.2 million square kilometres of land area to extremely dry and moist heat stress. The findings highlight the need for a coordinated clean air and climate strategy, addressing the emission sources of black carbon for efficient air quality and heat stress management.

Subject of Research: The role of black carbon aerosols in intensifying India's 2015 heatwave and expanding heat stress exposure

Article Title: Black carbon aerosols intensified India’s 2015 mega heatwave and expanded heat stress exposure

Article References: Tiwari, D., Sharma, A., Dhasmana, M. K., Mondal, A., & Venkataraman, C. (2026). Black carbon aerosols intensified India’s 2015 mega heatwave and expanded heat stress exposure. Communications Earth & Environment. https://doi.org/10.1038/s43247-026-04157-9

Image Credits: AI Generated

DOI: 10.1038/s43247-026-04157-9

Keywords: black carbon, aerosols, heatwave, India, heat stress, wet-bulb temperature, climate modelling, air quality, humidity, 2015 heatwave, Black, carbon