There is a general acceptance that there is a need to integrate climate change into medium to long-term water resources planning, which is being hampered by the large uncertainty associated to climate change projections. CRIDA was launched as a response to this gap and to integrate climate change uncertainty into the identification of (ecosystem-based) adaptation strategies and to enable flexible decision-making processes. Figure 1 gives an overview of the different steps of the Climate Risk Informed Decision Analysis.

Figure 1  The Climate Risk Informed Decision Analysis (CRIDA) approach to climate change adaptation

The impetus to develop CRIDA was not that climate projections were bad science but rather that the selection of a series of uncertain futures to plan for can lead to difficulties in recommending or justifying robust or adaptable projects.

The following are CRIDA principles that assist planners seeking to develop alternatives and justify plans that are robust or adaptable to deeply uncertain futures:

1. Identifying problems and opportunities about uncertain future change: Debates about selecting one, or several uncertain futures to plan for is often divisive and political. Stakeholders will often have an opinion about if, and how the future affects their interests. During problem formulation, CRIDA redirects attention away from future projections to a focus on system performance. The starting point is not what the future stresssors might look like, but rather what would chronic performance failure look like. Planning to avoid a critical failure threshold is less politically divisive (i.e. scenario planning of lost farm production has a stronger rallying cry than planning to mitigate impacts of temperature increases), and in a worst case scenario it returns the project to the expected debates between stakeholders. Moreover, the futures stressors that lead to failure will usually be combinations of future stressors, such as unprecedented urban development, market failure, and climate. In many of the CRIDA case studies, hyper urbanization was a primary stressor leading to failure, but highly exacerbated by the possibility to manage for more extreme drought and floods in the future.
2. Inventorying and forecasting conditions that lead to chronic failure: Assignments of probabilities or expectations to a future projection of a stressor is often not feasible in an increasingly uncertain world. Therefore, project performance is often evaluated with respect to a series of futures, usually under low, medium, and high levels of projected stress to a system. However, this only informs the planning team how the project performs under those established variables, which may be sufficient in some studies. However, the CRIDA framework seeks to ‘stress test’ system performance by iterative adjustment of uncertain inputs to identify all the combinations of stressors that lead to chronic failure. This allows the planning team to seek and quantify the conditions that the project would permanently fail, i.e. a vulnerability domain. A ‘stress test’ helps the planning team ask the right questions. Weather generators are an important tool to generate climatic input variables for a stress test.
3. Formulating alternative plans that are robust or adaptable: The formulation of actions or plans to mitigate against uncertain future stressors are developed collaboratively. This is important because the action or plans could require additional levels of robustness or flexibility that will need to be justified and be effective under uncertain higher levels of stress. Multi-purpose projects help justify incremental investments. Based on the previous assessments and the use of science to assess plausibility, four distinct strategies  guide the collaborative plan formulation:
   
   1. Standard planning guidance and safety margins are sufficient. No change in current procedures are necessary.
   2. The formulation of plans to mitigate incrementally plausible stressful futures that require more robust alternatives at different levels of magnitude;
   3. There are conflicting sources of evidence, lack of consensus on the evidence, and/or a low risk aversion by stakeholders that chronic failure is plausible. A recommendation for collaborative strategy to formulate ‘win-win’ plans with options for adaptability (i.e. ensure future alternatives, not taken today, are still possible tomorrow) is made.
   4. There is sufficient cause for concern for action but conflicting sources of evidence, lack of consensus on the evidence leads to disagreement on the magnitude for a first investment. A strategy to formulate acceptable initial robust alternatives with additional options for the future are recommended.
4. Collaboratively evaluating robustness or adaptability: Recommending alternatives that are more robust or adaptable may come at a cost, impact the environmental quality, regional economic development, or other social effects. If they provide benefits to all these four accounts the problem is solved, and the more robust or adaptable alternative should be preferred. However, given that a robust alternative explicitly means that it will provide performance as designed under a more stressful future, i.e. the alternative is more costly but provides similar output. Moreover, these costs may not be monetary or are a lost opportunity. To overcome this obstacle, the collaborative formulation of robust and adaptable alternatives with stakeholders is implemented identifying ancillary benefits that can be attributed to the other three accounts, and getting stakeholder buy-in towards the recommendation of a ‘locally preferred plan’. Under the CRIDA process the use of the vulnerability domain helps all parties understand plausible futures that would impair a project, and how much they might be willing to hedge their investment. The evaluation of ancillary benefits from robust or adaptable projects is based on stakeholder preferences.
5. Comparing robustness or adaptability of alternative plans: A principle challenge to planning under deep uncertainty is that all ‘discounted cash flow’ (DCF) analysis tend to bias plan selection decisions towards the least robust solution, when the future cannot be forecast with confidence. A number of factors contribute to this bias including the planning time horizon, aggregate levels of risk associated with various uncertain but plausible future conditions, and the inability to develop accurate expectations of future benefits and costs under deep uncertainty. However, two principles are brought into CRIDA to assist in this paradigm.
   
   1. The first is the identification of clear winners, e. plans which are preferred under all possible future scenarios.
   2. The second is in the use of Incremental Cost Analysis (ICA) to support additional investments in the mitigation of risks associated with various potential future scenarios. These investments above the baseline level of investment ensure that performance failures are avoided, when the future condition cannot be predicted with confidence.

Selecting a robustness or adaptability plan: The use of incremental cost analysis, or the use of clear winners permits a transparent way of justifying preferred levels of robustness or adaptability.  Moreover, the use of incremental cost analysis provides a tool to help shape some possible cost sharing arrangements in locally preferred plans, or special types of grants. Each increment that is selected to add robustness to an alternative has some ancillary benefit that a stakeholder cares about, and that they might be willing to sponsor. In addition, some grants often exist to subsidize best practices, which are accessible if an increment action is suited. In addition, increments may lead to multi-purpose projects allowing access to different sources of funds. For example, a CRIDA application in the city of Udon Thani, the formulation of added storage for robustness to increased floodwaters were linked to improved recreation, and thus sponsored by the city’s parks and recreation department.

Publications

Climate Risk Informed Decision Analysis (CRIDA): collaborative water resources planning for an uncertain future

Analyse décisionnelle basée sur le risque climatique (CRIDA): planification collaborative des ressources en eau en prévision d’un avenir incertain

Análisis de decisiones basadas en el riesgo climático (CRIDA): planificación colaborativa de los recursos hídricos para un futuro incierto