Gallery: Who's the Greenest of Them All?

Higher-education campuses are among the places where awareness of the environment and efforts to conserve energy and resources are the most intense.

Hundreds of U.S. colleges and universities have established sustainability offices to monitor and encourage efforts to save energy and water, recycle materials and cut down on waste. In addition, these schools offer thousands of classes to teach students how to carry out activities and live their lives in a more sustainable manner.

Several organizations keep track of green efforts at college campuses and compile rankings to measure the progress of these sustainable initiatives and inspire other institutions and individuals to step up their involvement in conserving resources.

Sierra Magazine's 2015 Cool Schools list of the greenest U.S. higher-education institutions shines a light on the efforts of 153 campuses. The Top 10 includes four schools in the University of California system; the list is topped, as it was in 2014, by the University of California, Irvine.