A heads-up to viewers in the United States: My sources at NBC Nightly News tell me that an investigative report on Peru’s pending water crisis will air on the show next Tuesday, Dec. 8, at 6:30 p.m. EST in many states. (Click here for state-by-state air times.)  NBC Nightly News crew films Anne Thompson’s interview with community leaders near Huaraz who are fighting to retain water rights (Oct. 2009) Environmental news correspondent Anne Thompson explores the accelerating retreat of tropical glaciers in Peru and the downstream effects of dwindling melt-water on agriculture, hydroelectricity and drinking water supplies for highlanders and coastal dwellers. Peru is among the three countries in the world most…