Chicago outlines plan to slash greenhouse gases

The mayor of Chicago announced a plan Thursday to dramatically slash emissions of heat-trapping gases as part of an effort to become one of the greenest cities in the United States.

The plan calls for greenhouses to be cut to three-fourths of 1990 levels by 2020 and to one-fifth of 1990 levels by 2050 by making buildings more energy efficient, finding clean and renewable energy sources, improving transportation and reducing industrial pollution.

Richard M. Daley was one of 800 U.S. mayors who agreed to cut emissions in accordance with the global agreement known as the Kyoto Protocol in late 2006. The U.S. government did not ratify the Kyoto Protocol.