The gains from growth, while distributed unevenly around the world, have been dramatic. Over the past 150 years life expectancy increased by around 30 years in most regions, including some of the world’s least developed. The growth dynamic that has yielded these improvements in living standards has imposed substantial costs on the physical environment on which human well-being ultimately depends. It is increasingly apparent that the current use of natural resources could put higher living standards and even conventionally measured growth at risk. Without decisive action, energy-related emissions of CO2 will double by 2050. Efforts to mitigate greenhouse gas (GHG) emissions, such as the Kyoto Protocol, will be less effective in reducing global emissions of GHG if countries with emission commitments source their carbon-intensive production activities from economies without such commitments, particularly if production in the latter countries is GHG-intensive.