CU Boulder has won many awards for its efforts in sustainability, including Sierra Club's as the Greenest School and the STARS Gold Rating. This is an honor and a challenge as CU students, faculty and staff are responsible for keeping our great school on top. CU strives to maintain this leadership in sustainability through renewable energy, green buildings, office conservation, and energy outreach and education. CU Boulder signed the Carbon Neutrality plan in 2009 and is lowering their carbon footprint each year despite the growth in building square footage. The CU Boulder Student Government and the two buildings they own are carbon neutral through the purchase of carbon offsets.