Adaptation has the potential to alleviate adverse impacts, as well as to capitalise on new opportunities posed by climate change. Since the TAR, there has been significant documentation and analysis of emerging adaptation practices. Adaptation is occurring in both the developed and developing worlds, both to climate variability and, in a limited number of cases, to observed or anticipated climate change. Adaptation to climate change is seldom undertaken in a stand-alone fashion, but as part of broader social and development initiatives. Adaptation also has limits, some posed by the magnitude and rate of climate change, and others that relate to financial, institutional, technological, cultural and cognitive barriers. The capacities for adaptation, and the processes by which it occurs, vary greatly within and across regions, countries, sectors and communities. Policy and planning processes need to take these aspects into account in the design and implementation of adaptation. The review in this chapter suggests that a high priority should be given to increasing the capacity of countries, regions, communities and social groups to adapt to climate change in ways that are synergistic with wider societal goals of sustainable development.
There are significant outstanding research challenges in understanding the processes by which adaptation is occurring and will occur in the future, and in identifying areas for leverage and action by government. Many initiatives on adaptation to climate change are too recent at the time of this assessment to evaluate their impact on reducing societal vulnerability. Further research is therefore needed to monitor progress on adaptation, and to assess the direct as well as ancillary effects of such measures. In this context there is also a need for research on the synergies and trade-offs between various adaptation measures, and between adaptation and other development priorities. Human intervention to manage the process of adaptation in biological systems is also not well understood, and the goals of conservation are contested. Hence, research is also required on the resilience of socio-ecological systems to climate change. Another key area where information is currently very limited is on the economic and social costs and benefits of adaptation measures. In particular, the non-market costs and benefits of adaptation measures involving ecosystem protection, health interventions, and alterations to land use are under-researched. Information is also lacking on the economy-wide implications of particular adaptations on economic growth and employment.