"The role of adaptation to climate change and variability is increasingly considered in academic research and its significance is being recognized in national and international policy debates on climate change."⁽¹⁾

Climate change impacts and adaptation is a multidisciplinary field of research that requires an integrative approach. In addition to considering a wide range of information from the natural sciences, climate change studies must also incorporate social, economic and political research. Increasing numbers of researchers are therefore becoming involved in impacts and adaptation research, and the field continues to grow and develop.

The First Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), published in 1990, was a strong influence in developing the United Nations Framework Convention on Climate Change (UNFCCC) in 1992. Research on climate change impacts at that time focused primarily on the potential consequences of different scenarios of greenhouse gas emissions and options for mitigation. Although the ability of adaptation to modify future impacts was recognized, as evident in Article 4 of the UNFCCC, adaptation generally received little consideration in these early studies.⁽²⁾

The decade following the release of the IPCC's First Assessment Report saw significant evolution of climate change impacts and adaptation research, due to a number of factors. First, there was growing evidence that climate change was already occurring,⁽³⁾ with significant consequences in some regions.^{(4, 5, 6)} Impacts could no longer be viewed as hypothetical outcomes of various emissions scenarios, but instead needed to be addressed as real and imminent concerns. Research was also suggesting that there would be changes in the frequency and intensity of extreme climate events, and that these changes would likely challenge human and natural systems much more than gradual changes in mean conditions would.⁽⁷⁾ In addition, it had become apparent that mitigation could not prevent climate change from occurring; temperatures would continue to rise even if stabilization of carbon dioxide were achieved.⁽⁸⁾ These factors led to recognition among the international climate change community that adaptation was a necessary complement to mitigation for reducing vulnerability to climate change.

This shift in attitude is reflected in the changing titles of the three IPCC Working Group II assessment reports completed between 1990 and 2001 (Table 1), as well as in a number of recent reports on approaches to impacts and adaptation research.^{(8, 9, 10, 11, 12)}

Table 1: Titles of the first, second and third assessment reports of IPCC Working Group II

In Canada, the first national assessment of climate change impacts and adaptation, the Canada Country Study, was published in 1998. This multi-volume report examined the impacts of climate change as well as potential adaptive responses across Canada's regions and economic sectors. This assessment of research revealed that, although traditional climate impacts studies (e.g., sensitivity analyses, baseline data gathering and model improvements) were still required, there was also a need to proceed with more integrative work that involved stakeholders, addressed costing issues and applied a more multidisciplinary approach. The Canada Country Study also concluded that limitations in scientific understanding of climate change should not delay the implementation of adaptations that would reduce vulnerability to climate change.

Reflecting these international and national trends in research, this chapter focuses first on the concepts, rationale and goals of understanding vulnerability to climate change. Vulnerability provides a basis for establishing priorities and helps direct research so that it better contributes to adaptation decision making. The next section provides an overview of the role of scenarios in impacts and adaptation research. Climate scenarios project the nature and rate of future changes in climate, which strongly influence vulnerability to climate change. The final section focuses on costing the impacts of, and adaptation to, climate change. Costing research, which includes consideration of both market and nonmarket goods and services, is seen as a key approach to providing quantitative estimates of vulnerability, and therefore influencing future adaptation and mitigation decision making.