The problem is easily stated. In 1950, the global emission of carbon dioxide was 6 billion tons a year. Thanks to population growth, urbanization, the expansion of wealth, and massive industrialization around the world, by 2008 this has increased fivefold to 30 billion tons a year. Assuming that nothing is done to reduce emissions, by 2058, they will be 60 billion tons a year. Thus, to reduce global warming, whose effects are already beginning to be felt, it will be necessary to take drastic measures just to stay at the present level, never mind actually making real progress. For example, to reduce the number of coal-fired generating plants, nuclear capacity in the United States will have to be doubled. To reduce car emissions, either Americans will have to drive half as many miles per year or cars will have to be twice as efficient. Buildings will have to use 25 percent less electricity …
Even assuming that anything at all gets built in the coming economic depression—during the Great Depression of the 1930s, building construction virtually halted—creating new cities and reconfiguring old ones will take many decades. We don’t have that much time.