For the first time in human history , more than half the world 's population is living in cities , which now produce approximately 70 percent of global greenhouse gas emissions . New York City Mayor Bloomberg is chairman of C40 Cities Climate Leadership Group . City leaders are taking action , not debating climate science , says Mayor . Hurricane Sandy emphasized importance of stronger infrastructure . Comment:
New York City Mayor Bloomberg is chairman of C40 Cities Climate Leadership Group . City leaders are taking action , not debating climate science , says Mayor . Hurricane Sandy emphasized importance of stronger infrastructure . Comment: