All climate is local.

For years scientists have urged national leaders to tackle climate change, based on the assumption that prevention efforts would require the coordinated actions of entire nations to be effective. But as anyone who has watched the past 15 years of international climate negotiations can attest, most countries are still reluctant to take meaningful steps to lower their production of greenhouse gases, much less address issues such as how to help developing countries protect themselves from the extreme effects of climate change. Frustrated by the ongoing diplomatic stalemate, a number of urban leaders have decided to take matters into their own hands, adopting solutions that already exist or inventing new ones for limiting greenhouse gas emissions and preparing for the effects of ongoing global warming. Mayors and urban managers are taking over because they have a keener sense about how changing weather patterns will affect their cities’ political and economic future. As Bärbel Dieckmann put it in 2007, when she was mayor of Bonn, Germany, “cities are already experiencing flooding, water shortages, heat waves, coastal erosion and ozonerelated deaths.” Since the mid-1990s, according to a 2009 report, the number of intense hurricanes has been increasing in the Atlantic Ocean, and the size of wildfires has been growing in the western U.S. As temperatures continue to rise, such extreme events may become even more frequent and severe. Most of the world’s major metropolises were originally built on rivers or coastlines and are therefore subject to flooding from rising seas and instances of heavier rainfall. Many civic leaders point to Hurricane Katrina and the devastation it visited on New Orleans in 2005 as their moment of awakening. They saw how the multiple failures of an aging and inadequate infrastructure, plus indifferent planning, sharply increased the death toll of a catastrophe that had long been predicted. Indeed, two major alliances of city mayors to combat climate change formed within months after Hurricane Katrina’s landfall. The organization now known as the C40 Cities Climate Leadership Group launched in London in October 2005, and the World Mayors Council on Climate Change (WMCCC) got its start in Kyoto that December. As of June 2011, more than 190 mayors and other local authorities, representing some 300 million people from around the world, have also signed a voluntary pact sponsored by the WMCCC to reduce greenhouse gas emissions. In some ways, cities may be in a better position than nations to do something about climate change. By conservative estimates, the cities of the world emit no less than 40 percent of such greenhouse gases as carbon dioxide, methane, nitrous oxide and fluorinated gases. According to a 2011 study by Daniel Hoornweg and his co-authors in the journal Environment and Urbanization, cities may actually be responsible for roughly 80 percent of emissions if one takes into account their consumption All Climate Is Local