Paleoclimate: Toward solving the UV puzzle

In English Decreases in stratospheric ozone caused by chlorofluorocarbons released into the atmosphere lead to an increase in harmful ultraviolet (UV) light received at Earths surface. But UV and ozone also vary naturally as a result of changes in solar activity. In their Perspective, Rozema et al. chart recent efforts to elucidate the relation among the solar UV spectrum, ozone concentrations, and harmful surface UV on decadal and longer time scales. Biological proxies (phenolic compounds in pollen and spores) can be used to reconstruct historical UV-B and total ozone.