Global dimming or local dimming?: Effect of urbanization on sunlight availability

[1] From the 1950s to the 1980s, a significant decrease of surface solar radiation has been observed at different locations throughout the world. Here we show that this phenomenon, widely termed global dimming, is dominated by the large urban sites. The global-scale analysis of year-to-year variations of solar radiation fluxes shows a decline of 0.41 W/m 2 /yr for highly populated sites compared to only 0.16 W/m 2 /yr for sparsely populated sites (