The decline of fog, mist and haze in Europe during the last 30 years: a warming amplifier?

Europe witnessed a strong surface warming during the last decades that reached more than twice the global warming rate. The brightening due to a decrease of aerosol burden and cloudiness in the lower troposphere is suspected to have contributed to this additional warming, but this link has not been quantified so far. From a statistical analysis of a large multi-decadal set of surface horizontal visibility data, we show that phenomena leading to low visibility such as fog, mist or haze strongly declined during the last three decades. Using an original statistical methodology linking local visibility changes with temperature changes, we show that this decline could have contributed on average to about 20% of recent daytime warming, and to more than 50% in parts of Eastern Europe.