The interaction of three variables underlie debates on the issue of climate change and what responses might be justified: the magnitude and rates of change of (1)population, (2)incomes, and (3)intensity of greenhouse gas emissions relative to economic activities. This book examines the interrelationships of the variables to explore their implications for policies that address climate change. Both internationally and domestically, initiatives are underway both to better understand climate change and to take steps to slow, stop, and reverse the overall growth in greenhouse gas emissions, the most important of which is carbon dioxide (CO2), emitted by the combustion of fossil fuels.