Ice cores drilled last year from the summit of a Himalayan ice field lack the distinctive radioactive signals that mark virtually every other ice core retrieved worldwide. That radioactivity originated as fallout from atmospheric nuclear tests during the 1950s and 1960s. These markers routinely provide researchers with benchmarks to gauge new ice accumulation. Scientists with Ohio State University's Byrd Polar Research Center believe the missing signal means the Naimona'nyi ice field has been shrinking at least since the A-bomb test half a century ago—foreshadowing serious water shortages in the future for more than 500 million people on the Indian subcontinent.
Julia Whitty is Mother Jones' environmental correspondent. You can read from her new book, The Fragile Edge, and other writings, here.