Fast facts about cities, climate change, and sustainability

• Less than 1: Percent of the earth’s surface covered by cities (1)
• 75: Percent of global energy consumed by cities (2)
• 80: Percent of global greenhouse-gas emissions contributed by cities (1)

• 6.7 billion: World population in 2007 (3)
• 50: Percent of world population expected to live in urban areas by the end of 2008 (3)
• 70: Percent of world population expected to live in urban areas by 2050 (3)

• 840: Mayors who have signed the U.S. Mayors Climate Protection Agreement (4)
• 50: States from which those signatories hail (4)
• 80 million: Citizens those signatories represent (4)
• 3: Actions those signatories agree to take (strive to meet or beat Kyoto goals in their communities; urge state and federal leaders to meet or beat Kyoto goals; urge Congress to pass bipartisan greenhouse-gas reduction legislation) (4)
• 110: Mayors who attended the November 2007 U.S. Conference of Mayors Climate Summit, the largest-ever meeting of U.S. mayors devoted solely to climate protection (5)

• 1,200: Tons of annual carbon emissions cut by replacing regular traffic-light bulbs with LEDs in Warwick, R.I. (6)
• 1,100: Tons of annual carbon emissions cut with free home energy retrofits in Houston, Texas (2)

• 30: Percent increase in public transportation use in the U.S. between 1995 and 2006 (7)
• 24: Percent increase in vehicle miles traveled in the U.S. during the same time (7)
• 88: Percent of all trips taken by car in the U.S. (8)

• 48: Percent of U.S. greenhouse gases contributed by the building sector, primarily through energy consumption (9)
• 50: Percent of the “built environment” expected to be rebuilt by 2030 (10)
• 1.7 billion: Estimated tons of carbon that could be saved by large-scale conversion to greener buildings in North America by 2030 (11)
• 418: Percent increase in number of cities with green building programs between 2003 and 2007 (12)

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