Traces of nuclear weapons testing and accidents have been found in glaciers across the planet.

Fallout radionuclides had previously been found at glaciers relatively close to the sites of nuclear events, such as the Austrian alps after the Chernobyl disaster of 1986 . But researchers have now discovered that these radionuclides are spread more widely, and can persist for decades after their release.

Caroline Clason of Plymouth University, UK, and her colleagues have detected radionuclides at 17 sites …