In widely separated locations in both hemispheres, we have found a significant correlation between the increased concentrations of 210Pb in glacier ice and periods of nuclear tests. The concentrations of 2i0Pb fluctuated concurrently with 137Cs concentrations in all glaciers studied, except for a temperate glacier in the Alps, exposed to the effects of summer heat. The most strict concurrence of fluctuation of these nuclides was observed in Spitsbergen, a location comparatively close to the arctic testing grounds. In 1973, a large excursion of 210Pb concentration was observed in all glaciers studied south of the arctic, presumably after testing an advanced thermonuclear device at Lob Nor. The concurrence of concentrations of 210Pb, i37Cs, and 90 Sr was observed in samples of stratospheric aerosols collected at an altitude of 12 km. This indicates that a part of the 2i0Pb present in the environment was produced, together with fission products, by nuclear explosions.