Yale Environment 360: Last fall, the climate advocacy group 350.org held a series of rallies in 21 cities across the U.S., making the case that combating climate change requires fossil fuel companies to leave a large portion of their reserves in the ground -- and that large-scale divestment by their shareholders could help convince them to do so. Since then, four small U.S. colleges have committed to ridding their endowments of fossil fuel investments, and more than 250 other colleges and universities have spawned student-...