Adaptation 

Human-driven adjustments in ecological, social or economic systems or policy processes, in response to actual or expected climate stimuli and their effects or impacts (LEG, 2011). Various types of adaptation can be distinguished, including anticipatory and reactive adaptation, private and public adaptation, and autonomous and planned adaptation (IPCC Fourth Assessment Report (AR4), 2007). 

Adaptation benefits 

The avoided damage costs or the accrued benefits following the adoption and implementation of adaptation measures (IPCC AR4, 2007).
 

Adaptation costs 

Costs of planning, preparing for, facilitating and implementing adaptation measures (IPCC AR4, 2007). 
 

Adaptive capacity (in relation to climate change impacts)

The ability of a system to adjust to climate change (including climate variability and extremes) in order to moderate potential damages, to take advantage of opportunities or to cope with the consequences (IPCC AR4, 2007).
 

Maladaptation 

Any changes in natural or human systems that inadvertently increase vulnerability to climatic stimuli; an adaptation that does not succeed in reducing vulnerability but increases it instead (IPCC Third Assessment Report, 2001).
 

Climate change 

Refers to any change in climate over time, whether due to natural variability or as a result of human activity (IPCC AR4, 2007).
 

Climate variability 

Variations in the climate (as measured by comparison with the mean state and other statistics such as standard deviations and statistics of extremes) at all temporal and spatial scales beyond that of individual weather events. Variability may be due to natural internal processes within the climate system (internal variability) or to variations in natural or anthropogenic external forcing (external variability) (IPCC AR4, 2007). 
 

Resilience 

The ability of a social or ecological system to absorb disturbances while retaining the same basic structure and ways of functioning, the capacity for self-organization and the capacity to adapt to stress and change (IPCC AR4, 2007).
 

Vulnerability 

The degree to which a system is susceptible to, or unable to cope with, adverse effects of climate change, including climate variability and extremes. Vulnerability is a function of the character, magnitude and rate of climate variation to which a system is exposed, its sensitivity and its adaptive capacity. Therefore adaptation would also include any efforts to address these components (IPCC AR4, 2007).
 

Mainstreaming or integration 

The integration of (adaptation) objectives, strategies, policies, measures or operations such that they become part of the national and regional development policies, processes and budgets at all levels and stages (Lim and Spanger-Siegfred, 2005).
 

Sources: 

McCarthy JJ, Canziani OF, Leary NA, Dokken DJ, White KS (eds). 2001. Climate Change 2001: Impacts, Adaptation, and Vulnerability. Contribution of Working Group II to the Third Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge: Cambridge University Press.
 
Parry ML, Canziani OF, Palutikof JP, van der Linden PJ and Hanson CE (eds). 2007. Impacts, Adaptation, and Vulnerability. Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge: Cambridge University Press.
 
Lim, B, and Spanger-Siegfred, E (eds). 2005. Adaptation Policy Framework for Climate Change. Developing Strategies, Policies and Measures. Cambridge: Cambridge University Press. Available at
 

Least Developed Countries Expert Group. 2012. National Adaptation Plans. Technical guidelines for the national adaptation
plan process. Bonn: UNFCCC secretariat. Bonn, Germany. December 2012.<http://unfccc.int/7279>

​Least Developed Countries Expert Group. 2012. National Adaptation Plan Process: A brief Overview. Bonn: UNFCCC secretariat. Bonn, Germany. December 2012.<http://unfccc.int/7279>