Mayor Michael Bloomberg of New York rarely minces his words. He also puts his wealth where his mouth is.
Mr. Bloomberg, who believes that governments are doing too little to address the problem of global warming, is donating $50 million to the Sierra Club’s grass-roots campaign to block the construction of new coal-fired power plants and shut down existing ones. (Coal provides nearly half the nation’s electricity and about one-third of its emissions of carbon dioxide.) In May, he pledged nearly $20 million to C40, a group of cities around the world that are trying to reduce greenhouse gases.