In recent years, the problem of climate change has captured an unprecedented level of attention. This has mobilized the international community to agree on mitigation actions, boosted technological innovation efforts to develop the necessary tools to address the causes of the problem and generated growing concerns about the potentially negative impacts of this phenomenon on countries' economic and social development. This issue has even been included, together with the Millennium Development Goals, on the agenda of priorities of the United Nations Secretary-General. The overriding concern worldwide is, rightly, to tackle the root of the problem, greenhouse gas emissions (GHGs);, before the feedback loops in the system become irreversible. The release of GHGs into the atmosphere and their build-up over the past few centuries has raised concentrations to such a point that the Earth's temperature is rising to dangerous levels. The international regime agreed to under the United Nations Framework Convention on Climate Change (UNFCCC); and the Kyoto Protocol limits the emission of GHGs, but only in the developed countries. The use of the atmosphere as a sink for anthropogenic GHGs is thus only partially regulated, and the regime is still far from ensuring climate security. It was not until 2007 that quantitative targets and deadlines were set for attaining climate security, which, as Bárcena points out, is a global public good that must be protected (Bárcena, 2008 and 2009a and b; El Universal , 2008);. The Stern Review on the Economics of Climate Change and the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC); provided fresh input to make limit-setting possible (Stern, 2006);. The IPCC dispelled the uncertainty as to the responsibility of human activity for climate change and the damage that this phenomenon could potentially cause under different scenarios. The Stern Review, meanwhile, in addition to providing estimates of the global costs of mitigation, showed that any delay in taking action would result in more substantial losses in terms of welfare and global output and steered the discussion towards the establishment of very low discount rates in the future and the need to act immediately. This report examines what has become the standard for climate security in the industrialized countries and some emerging economies: capping GHG concentrations in the atmosphere at between 500 and 550 parts per million (ppm); of CO 2 e, which would suppose a global temperature rise of between 2.5°C and 3.5°C. Above this level, all systems would be facing changes of such a magnitude that the possibilities of adaptation would be slim. concentration level is about 430 ppm of CO 2 e. At this rate, the 550 ppm concentration limit will be reached by the middle of this century, and emissions will still be increasing. Time for stabilizing concentrations at safe levels is therefore running out fast. The situation in Latin America and the Caribbean is different from that of the developed countries. The latter are the main source of the emissions creating this new global reality and they are suffering some consequences; whereas the countries of Latin American and Caribbean region have contributed little to this situation and are suffering the consequences to a disproportionate extent. By region, the Latin American and Caribbean region is the second lowest emitter in the world (after Africa);. In terms of per capita emissions, however, its levels exceed those of both Asia and Africa. Nevertheless, the Latin American and Caribbean region is one of the most vulnerable to climate change for several reasons: many of its countries are island States or have coastal lowlands and are located in the hurricane belt; others depend on the thaw of the snow and ice deposits in the Andes to supply water to their urban and agricultural sectors; and several are at high risk from major disasters such as floods and forest fires. These geographical features, together with the situation of Latin America and the Caribbean in the global economy, are precisely why it is so necessary to carry out a specific analysis of the impacts of climate change on the region. Until quite recently, the discussions were focused on the environmental impact of this phenomenon and only in the past few years has attention turned to the economic implications. This book of the Economic Commission for Latin America and the Caribbean (ECLAC);, which seeks to help bridge the gap between the environmental and economic spheres, presents an initial analysis of the most relevant information on the region available in 2009. It also underscores some economic aspects of climate change and their implications for Latin America and the Caribbean, in particular the link with international trade, the negative effects on public finances and the future constraints on highcarbon economic development. Climate change will hamper development because resources will be lost or will have to be reallocated to adaptation to its negative impacts. However, this phenomenon also offers the world an opportunity to pursue a better quality of development through more investment in technologies that can mitigate some of the negative environmental impacts of the development process. Economic decision-makers in the Governments of the region need to be made aware of these issues; indeed, the better prepared they are, the less pressure they will be under in terms of unforeseen expenses and loss of revenues and the better the economic governance of the country in question. In short, this book seeks to provide Latin American and Caribbean Governments with input for analyzing the relationship between climate change and development. This text stresses the importance of finding mechanisms for appropriately distributing the costs of climate change. It also points out that major changes are on the way in the global context in which the countries of Latin America and the Caribbean operate and that steps will have to be taken to ensure that the carbon footprint is factored into trade and future-investment decisions. The information presented in this book will be complemented in the near future with the results of studies on the economics of climate change that are being carried out in different countries across the region ( Brazil, Mexico and some Central American, South American and Caribbean nations);. As new data is incorporated, these studies will provide an increasingly accurate picture of the costs of adaptation at the national and sectoral level and of the potential gains of mitigation. Information on most of the countries of Latin America and the Caribbean should be available in 2010, which will enhance the analysis of the issue from the regional perspective. The literature reviewed in the preparation of this book included recent international works on climate change covering Latin America and the Caribbean, such as the 2030 scenarios published by the International Energy Agency, the Fourth Assessment Report of the IPCC and the reports prepared by the United Nations Environment Programme (UNEP); and the United Nations Development Programme (UNDP);. These documents stress the importance of adaptation as a strategy for the region, highlight the possible gains of mitigation, with and without carbon markets, and underscore the need to protect public finances against the effects of physical or economic disasters that could bring down income levels or drive up expenses. In concluding, I should like to express my appreciation to Joseluis Samaniego, Director of the Sustainable Development and Human Settlements Division of ECLAC, for coordinating the preparation of this document; to the Division of Production, Productivity and Management, under the leadership of Mario Cimoli, for its inputs on the impacts on the primary sector; and to the Natural Resources and Infrastructure Division, under Hugo Altomonte, for its collaboration on issues relating to the energy sector. Alicia BárcenaExecutive SecretaryEconomic Commission for Latin Americaand the Caribbean (ECLAC);