Bloomberg: Why Sandy forced cities to take lead on climate change

Water from Hurricane Sandy rushes into the Carey Tunnel in the Financial District of New York on October 29, 2012.

STORY HIGHLIGHTS

• 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
• New York is prepping for future storms and cutting emissions

Editor's note: Michael R. Bloomberg is the Mayor of New York City and is the Chair of the C40 Cities Climate Leadership Group, a network of the world's largest and innovative cities taking climate actions on a local level. "The City" is a CNN special theme week series that airs from Monday Aug 19 on "World Business Today" at 1300 GMT and "Connect The World" at 2000 GMT.

(CNN) -- 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. That puts cities on the frontlines of the battle against climate change -- and more and more cities are leading the charge.

In New York, we began a frontal attack on climate change in 2007 with the release of our sustainability blueprint, PlaNYC -- and since then we've made major progress. For instance, we are well on our way to meeting our goal of reducing our greenhouse gas emissions by 30 percent by 2030.