Regional context

This chapter serves as an introduction to Part B of this volume. It provides context for an assessment of regional aspects of climate change in different parts of the world, which are presented in the following nine chapters. While the main focus of those chapters is on the regional dimensions of impacts, adaptation, and vulnerability (IAV), this chapter also offers links to regional aspects of the physical climate reported by Working Group I (WGI) and of mitigation analysis reported by Working Group III (WGIII). The chapter frames the discussion of both global and regional issues in a decision-making context. This context identifies different scales of decisions that are made (e.g., global, international, regional, national, subnational, local) and the different economic or impact sectors that are often the objects of decision making (e.g., agriculture, water resources, energy). Within this framing, the chapter then provides three levels of synthesis. First there is an evaluation of the state of knowledge of changes in the physical climate system, and associated impacts and vulnerabilities, and the degree of confidence that we have in understanding those on a regional basis as relevant to decision making. Second, the regional context of the sectoral findings presented in Part A of this volume is discussed. Third, there is an analysis of the regional variation revealed in subsequent chapters of Part B. In so doing, the goal is to examine how the chapters reflect differences or similarities in how decision making is being addressed by policy and informed by research in different regions of the world, and whether there is commonality of experience among regions that could be useful for enhancing decisions in the future. Having analyzed similarities and differences among IPCC regions, the chapter then discusses trans-regional and cross-regional issues that affect both human systems (e.g., trade and financial flows) and natural systems (e.g., ecosystem migration). Finally, the chapter evaluates methods of assessing regional vulnerabilities and adaptation, impact analyses, and the development and application of baselines and scenarios of the future. These evaluations provide guidance for understanding how such methods might ultimately be enhanced, so that the confidence in research about possible future conditions and consequences might ultimately improve.