Entering the adaptation learning cycle at the stage of identifying adaptation measures requires that an adaptation problem has been identified. Once a problem has been identified, the adaptation challenge is characterised by actors facing current and future vulnerability and impacts, who must identify adaptation measures (also called alternatives, strategies, actions). There is a wealth of methods from the fields of organisational learning, decision analysis, policy analysis, institutional and behavioural analysis that may be applied towards this end and this section guides the reader though selecting an appropriate approach.

The particular approaches applicable at this stage differ between for decisions faced by public actors and those faced by private actors. We therefore treat the identification of measures for private and public actors in separate subsections. Private actors act in their private interest and the identification of measures is a more narrowly defined task. Public actors, on the other hand, are mandated to decide in public interest and have jurisdictional power to influence the behaviour of others. In identifying measures, a public actor thus needs to consider a much wider array of measures and criteria, such as distributional effects and potential conflicts that may arise. As a consequence, a different set of tasks are applicable. As public adaptation situations are more complex and require influencing the behaviour of others, research methods are salient. In particular behavioural and institutional research can play an important role in understanding and identifying suitable measures.

Some methods for identifying adaptation measures are relevant across different adaptation situations. For example, approaches make use of current climate variability and the practices employed to respond to it, as a starting point for identifying adaptation measures. Thus, describing behavioural and institutional responses in place to cope with climate variability may be an important step in identifying adaptation measures. These responses may be inventoried and analysed in conjunction with key stakeholders in a given sector or region. However, in such processes, adaptation to climate change is often only considered as an extension of coping with known climate hazards, and so may fail to address features of a changed climate that are well beyond local experience. Therefore, identification of adaptation measures often may make use of expert judgment (UNDP, 2009) or identification of theoretically appropriate adaptation measures (Ebi and Burton, 2008) from which decision analysis methods can then prioritise.

Further, the use of experiments and research and development (R&D) may lead to the identification of adaptation measures, e.g., new crop varieties or design technologies. These methods are also relevant across different adaptation situations.

A number of barriers may arise both in identifying and appraising measures, in particular for situations involving collective adaptation. In such situations, leadership, authority and skill are critical factors in the process of identifying and selecting measures. Effective leadership, for example, is often essential to applying methods for consensus building successfully, or for generating measures in a brainstorming process. While an actor's lack of sufficient authority or jurisdiction to implement an identified adaptation measure may lead to the perception of difficulties arising in the implementation phase, and thus identifying measures may to some extent be constrained by whose 'jurisdiction' measures are perceived to be in by actors and how open the actors are to generating measures beyond their immediate control. Many things such as different missions, levels of power and authority, political interests, funding and so on, can affect this. Finally, as mentioned earlier, actors must have sufficient knowledge, awareness, skill and financial resources to be able to carry out the methods associated with each task. These are barriers related to pragmatic criteria for identifying tasks and selecting methods and are not incorporated into the decision trees because they arise in specific contexts. Therefore, it is important to be aware of these potential barriers, at each stage of the process.