Introduction: review of adaptation decision tools
Several tools have been developed to support climate adaptation decision-making over the past decade. Tools target different points of the adaptation planning policy cycle. Some aim at screening climate risks of projects and programmes, some intend to identify opportunities for institutional change and adaptive capacity building, others build on spatial analysis of vulnerability to assess adaptation needs, and others use information on climate impacts to support adaptation planning. Tools also differ in that some use more quantitative data, while others build on qualitative information or a mix of both. Another difference is in the spatial scale they cover. Some tools target a specific scale, for example either local or national, while other tools can be applied to a cross-scale analysis, for instance, considering groups of actors at multiple governance levels. The different aspects described above for different tools are illustrated here.
In general terms, the diversity of tools available in adaptation research can be classified in two distinctive approaches or framings of adaptation:
- a “top-down” approach
- a “bottom-up” approach
In the top-down framing, adaptation relates to decisions that are taken on the basis of simulated climate scenarios downscaled to a regional level and fed into impact models to estimate potential impacts. Based on this, adaptation measures are then identified and evaluated via multi-criteria, cost-effectiveness or cost-benefit analysis (Carter et al. 1994, 2007, Adger et al. 2007).
In the bottom-up approach, adaptation is framed as a social and institutional process that involves many actors and many decisions at different levels. Outcomes of actions can usually not be predicted because they depend on actions and interactions of many actor groups as well as the social and cultural context. Focal points of this type of analysis are ‘formal and informal rules in use’ (Ostrom 2005), or the formal and informal ‘institutions’ that define the interaction between actors.