IPCC Fourth Assessment Report: Climate Change 2007
Climate Change 2007: Working Group II: Impacts, Adaptation and Vulnerability

17.4.2 Limits and barriers to adaptation

Most studies of specific adaptation plans and actions argue that there are likely to be both limits and barriers to adaptation as a response to climate change. The U.S. National Assessment (2001), for example, maintains that adaptation will not necessarily make the aggregate impacts of climate change negligible or beneficial, nor can it be assumed that all available adaptation measures will actually be taken. Further evidence from Europe and other parts of the globe suggests that high adaptive capacity may not automatically translate into successful adaptations to climate change (O’Brien et al., 2006). Research on adaptation to changing flood risk in Norway, for example, has shown that high adaptive capacity is countered by weak incentives for proactive flood management (Næss et al., 2005). Despite increased attention to potential adaptation options, there is less understanding of their feasibility, costs, effectiveness, and the likely extent of their actual implementation (U.S. National Assessment, 2001). Despite high adaptive capacity and significant investment in planning, extreme heatwave events continue to result in high levels of mortality and disruption to infrastructure and electricity supplies in European, North American and east Asian cities (Klinenberg, 2003; Mohanty and Panda, 2003; Lagadec, 2004; Poumadère et al., 2005).

This section assesses the limits to adaptation that have been discussed in the climate change and related literatures. Limits are defined here as the conditions or factors that render adaptation ineffective as a response to climate change and are largely insurmountable. These limits are necessarily subjective and dependent upon the values of diverse groups. These limits to adaptation are closely linked to the rate and magnitude of climate change, as well as associated key vulnerabilities discussed in Chapter 19. The perceived limits to adaptation are hence likely to vary according to different metrics. For example, the five numeraires for judging the significance of climate change impacts described by Schneider et al. (2000b) - monetary loss, loss of life, biodiversity loss, distribution and equity, and quality of life (including factors such as coercion to migrate, conflict over resources, cultural diversity, and loss of cultural heritage sites) - can lead to very different assessments of the limits to adaptation. But emerging literature on adaptation processes also identifies significant barriers to action in financial, cultural and policy realms that raise questions about the efficacy and legitimacy of adaptation as a response to climate change.