Eighty percent of New York City's pollutants come from buildings and 20 percent from transportation. This is a reversal from most cities, which see pollution from transportation rather than high density buildings, explains New York's Mayor Bloomberg. The mayor is in Sao Paolo, Brazil for a meeting on climate change. "There's an awful lot that has to be done on a national and an international level, says mayor Bloomberg. "But at the same time, mayors are held accountable to deliver services and are trying to do things at a local level."

A group of mayors from around the country, including New York City's Michael Bloomberg, are awarding a new set of grants on Martin Luther King Jr. Day. The grants will go to ten cities, and are designed to encourage service in urban areas.

New York City Mayor Michael Bloomberg is in Copenhagen this week to take part in the Climate Summit for Mayors.  Last week, the Mayor passed his Greener, Greater, Buildings Plan, and this week he hopes to inspire leaders from other cities to follow suit. With cities around the world producing more than 80 percent of global carbon dioxide emissions, changes in urban systems can have green effects globally. We speak with Bloomberg from Copenhagen.  (click through for the full interview transcript)