Fossil fuel combustion is the single largest human influence on climate, accounting for 80% of anthropogenic greenhouse gas emissions. This paper presents trends in world carbon dioxide (CO2) emissions from fossil fuel combustion worldwide, based on the estimates of the International Energy Agency (IEA) [IEA, 2006a. CO2 Emissions from Fuel Combustion 1971-2004. International Energy Agency, Paris, France]. Analyzing the drivers of CO2 emissions, the paper considers regions, types of fuel, sectors, and socioeconomic indicators. The paper then examines the growing body of climate change mitigation policies and measures, both multinational and federal. Policies discussed include the Kyoto Protocol, the European Union Emissions Trading Scheme, and the potential measures to be implemented in 2012 and beyond. CO2 emissions of recent years have grown at the highest rates ever recorded, an observed trend incompatible with stabilizing atmospheric concentrations of greenhouse gases and avoiding long-term climate change. Within this aggregate upward trend, a comparison of emissions sources proves dynamic: while industrialized countries have so far dominated historical emissions, rapid growth in energy demand of developing economies, led by China, may soon spur their absolute emissions beyond those of industrialized countries. To provide context for the drivers of CO2 emissions, the paper examines fuel sources, from coal to biofuels, and fuel use in the production of heat and electricity, in transport, in industrial production and in households. The sectoral analysis illustrates the primacy, in terms of emissions growth and absolute emissions, of two sectors: electricity and heat generation, and transport. A discussion of several socio-economic emissions drivers complements the paper's analysis of mitigation mechanisms. As illustrated, emissions per capita and emissions per unit of economic production, as measured in gross domestic product (GDP), vary widely between regions. In this context, the paper examines the constraints and choices of energy use in two prominent developing economies: China and Brazil. This analysis of long-term trends in CO2 emissions from fuel combustion will prove useful for policyrnakers and energy policy analysts alike. Understanding the sources and drivers of greenhouse gas emissions is essential to their worldwide management and to the mitigation of climate change. (C) 2007 OECD/IEA. Published by Elsevier Ltd. All rights reserved.