FILE - In this Aug. 12, 2016 file photo, a group of tourists walk in front of the Tuco glacier in Huascaran National Park during a tour called the &quot;Route of climate change&quot; in Huaraz, Peru. The tropical glaciers of South America are dying from soot and rising temperatures, threatening water supplies to communities that have depended on them for centuries. (AP Photo/Martin Mejia, File)