Whitewashing a mountain to save a glacier

BBC : On the Chalon Sombrero peak in Peru, site of an extinct glacier in a remote corner of the Andes, four men have been whitewashing the summitâmdash;a project of Peruvian Eduardo Gold, a winner of the World Bank’s 2009 “100 Ideas to Save the Planet” competition. More than 70% of the world’s tropical glaciers are in Peru, and global warming has melted 22% of them in the last 30 years. Gold based his idea on the principle that white reflects sunlight, sending solar energy back out into space, rather than warming Earth’s surface. Changing the albedo (the fraction of light reflected) of the rock could cool the peak’s surface, says Gold, which in turn could cause the glacier to re-grow. Although some express doubt that this will work, the process is relatively inexpensive and environmentally friendly, which led Peru’s climate change chief, Eduardo Durand, to give it the green light.