Climate change - city heatwaves increase when polluting aerosols are reduced

   aerosol cover in cities                    Shutterstock

In one of the more perverse impacts of environmental monitoring and pollution control, researchers have found that heatwaves increase as harmful aerosol pollution is reduced for the purpose of obtaining cleaner air. The warming has been found to be greater in populated locations where, commensurately, there tends to be more air pollution.

Aerosols cause lower temperatures as they reflect sunlight away from the planet either through altering the cloud composition or as a direct effect. Cleaning up the air and removing aerosols for better human health has resulted ironically in increasing heatwaves and generally warming the climate. Researchers have found that for most of last century, heatwave frequency was slowed despite rising greenhouse gas emissions. This changed from 2005 as declines in polluting aerosols became more apparent. A related issue is that aerosol pollution may have masked up to half the warming effect of greenhouse gas emissions up till now. The net impact has been that aerosol reduction has added heatwaves across the planet by approximately two days per decade.

The research Article can be accessed at this link: Anthropogenic aerosol changes disproportionately impact the evolution of global heatwave hazard and exposure