global dimming
gradual reduction in the amount of global direct irradiance at the Earth's surface; approx. 4% reduction over 1960–1990; caused by an increase in atmospheric particulates (e.g. sulfate aerosols) due to human action
en-GB/ˈɡləʊbl ˈdɪmɪŋ/
en-US/ˈɡloʊbəl ˈdɪmɪŋ/