European employees work fewer hours per year, and use less energy per person, than their American counterparts. This article compares the European and U.S. models of labor productivity, supply, and energy consumption. It finds that if employees in the EU-15 worked as many hours as those in the United States, they would consume at least 15 percent more energy. This aspect of the debate over Europe's economic model reaches globally. Over the coming decades, developing countries will decide how to make use of their increasing productivity. If, by 2050, the world works as do Americans, total energy consumption could be 15 to 30 percent higher than it would be if following a more European model. Translated directly into higher carbon emissions, this could mean an additional 1 to 2 degrees Celsius in global warming.