A pathways approach to adaptation planning is about keeping options open and so avoiding path dependency and lock-in (as explained in the Overview of adaptation). It provides structure and guidance to help incorporate flexibility into adaptation planning. It can reduce unnecessary expenditure, preventing organisations from being locked into actions that may not be the best solutions for what is a long-term problem. Under the approach, rather than determining a final outcome or decision at an early stage, decision makers are able to build a strategy that will follow changing circumstances over time. The approach acknowledges that while not all decisions can be made now, they can be planned, prioritised and prepared for. It is a useful approach for dealing with uncertainty, especially in cases where the uncertainty may reduce over time, for example with improvements in estimates of future local sea-level rise.

What is a ‘pathways approach’ and how can it be used in adaptation planning?

An adaptation pathway is a decision-making strategy that is made up of a sequence of manageable steps or decision-points over time. Characteristics of the strategy are:

• Each decision-point is triggered by some change (environmental or social).  In the design of the strategy, the steps and the triggers must be identified (see Box 1 for definitions).
• Each decision-point has a series of identified choices or options associated with it.
• Once the decision-point is triggered, the options for that step are ‘tested’ against plausible futures and the acceptable risk to the organisation or community, and a selection is made.
• The selection leads to the next section of the pathway, and in turn to the next decision-point.
• The options that are not selected will, if appropriate, be available for selection at the next decision-point.  The wide range of options considered, evaluated and left on the table for the future gives decision makers flexibility and allows decisions to be responsive and iterative.

This approach helps to deal with the deep uncertainty associated with climate change. This comes from a number of sources of uncertainty, including:

• in the future projections of climate change and their impacts (see Accessing climate scenarios)
• in how societies will evolve over time – how economies will grow, how populations will increase, how technologies will change
• about the range of adaptation options that will be available in future, their associated costs, social acceptability and feasibility.

Uncertainty makes it unlikely that successful adaptation solutions will be one-off and static. They will need to be flexible and responsive to changing circumstance.  The concept of ‘adaptation pathways’ has emerged to address these challenges.  A pathways approach should guide decisions away from maladaptation and reduce exposure to risks that are considered unacceptable to the community.

The adaptation pathway approach has been successfully applied in adaptation planning for infrastructure projects, e.g. the Thames Barrier as described in Box 2, water management projects (Haasnoot et al. 2013) and broader cross-sector adaptation planning, e.g. in the Eyre Peninsula (South Australia) as described in Box 3.  An example developed to engage the community in decision-making around coastal management is shown in Figure 2 (Barnett et al. 2014).

The decision pathway and its adaptation options can be illustrated in the form of a ‘route map’ or similar diagram. Examples of these route maps are shown and discussed in Box 2 and Box 3. Not all adaptation planning can be neatly captured in a route map, but the principles of a pathways approach remain useful.

Why would you use the pathways approach?

The pathways approach promotes adaptive management — it enables adaptation plans to be ongoing by incorporating flexibility and adaptability into the decision-making process. Not all decisions must be made immediately and options can remain on the table. This prevents decisions being made now that lock decision makers out of other options in the future.

Key advantages of the pathways approach are:

1. It buys time to plan and reduces the pressure of making decisions now.

An ongoing process of monitoring and evaluation identifies the trigger points at which further decisions or actions will need to be undertaken. This should help remove the pressure of making all decisions now. It also creates time to build strategies for funding, gain community support and generate the necessary knowledge to implement future decisions. Importantly, it can help identify the first steps that can be taken.

2. It reduces uncertainty by using events not time as decision points

 A key characteristic of the pathways approach is that the triggers for the decision points are scaled against events, not time.  Events might be related to sea-level rise, flooding, or heat-waves— any climate-related occurrence that is expected to get worse as a result of climate change. Therefore, the pathway is independent of time, removing one source of uncertainty (the timing of the event). 

3. Its flexibility enables the plan to reflect local circumstances

The flexibility of the pathways approach allows for plans to respond not only to changes in climate but also changes in the risk appetite of communities. For example, following Hurricane Sandy, the City of New York used the flexibility of their adaptation pathways approach to meet a reduced appetite for risk among its residents (Rosenzweig and Solecki 2014).

4. It keeps options open until there is more information, funding or support for options

Keeping options open enables managers to hold off making decisions that may be expensive, until better information is available about the impacts of climate change. It allows sequencing of adaptation options, starting from low controversy, soft options and only moving to higher impact more expensive options as certain thresholds are reached.

5. It allows for learning by along the adaptation journey

A possible risk of using a pathways approach, which is common to all adaptation planning, is that it may lead to undesirable or maladaptive outcomes. While the process is intended to help avoid this, it is important to recognise that there is always a risk with making decisions under uncertainty. Using the pathways approach allows the opportunity to learn from the outcome of past decision-making, to incorporate that learning into future decision-making, and to build a better understanding of managing future risks.

The theoretical basis

The pathways approach is a response to the growing awareness that adaptation demands dynamic, long term and transitional approaches that can accommodate uncertainty and avoid future maladaptation, and that on-ground practitioners need the tools to move beyond strategic planning and into taking action.

Early examples of the application of a pathways approach involved considerable investment to model a large number of scenarios for engineering solutions (e.g. planning for the risk of flooding and sea-level rise in the Thames Estuary, London, UK, see Box 2). Many organisations contemplating adaptation in Australia are small with limited in-house capacity and technical expertise and a stronger reliance on community consensus. There are a number of case studies that incorporate  the pathways approach into adaptation plans that are more focused on community participation and consensus (Barnett et al. 2014; SGS Economics and Planning 2012; Siebentritt et al. 2014). This emphasis on a low-cost, participatory approach is described in Eyre Peninsula: adaptation policy making.

How would you undertake a pathways approach?

Making effective use of the adaptation pathways approach requires a shift in emphasis toward thinking about the decision-making process, the types of decisions that can and need to be made, and the barriers posed by the decision context (i.e. the institutions, preferences, norms, etc.) to identifying and implementing adaptation options. Particular questions that need to be addressed include:

• How are individual decisions connected (does one decision depend on another being taken)?
• The timing of adaptation options: How long will an adaptation option be effective in reducing climate risks? What is the lead-time needed to implement an action? What resources are available now and potentially in the future?

Some options may need to be considered that are a significant departure from customary practice or that require significantly different cultural, political or governance mindsets. These options are generally referred to as transformative adaptation. They will often require new governance or social structures to be established in preparation for the transformation.

There are a number of different ways to undertake an adaptation pathways approach, but in general the approach covers the following:

1. Defining and scoping the areas of decision-making including determining the objectives or a vision of what success might look like. The results of this scoping exercise can be used to identify stakeholders and elicit their values.
2. Determining thresholds and trigger points – see Box 1 for definitions. Achieving this step is likely to involve stakeholder consultation and/or interrogation of future climate change scenarios and projections.
3. Determining the range of adaptation options and their lead-times and then making an evaluation of each option in terms of a set of criteria involving cost, community acceptability, time to implement, technical complexity etc.  Two tools that are likely to useful in this exercise are:
   
   1. A checklist that allows each option to be evaluated against the criteria
   2. Backcasting, i.e. working back from the desired outcome to the present day to understand what steps are required to arrive at the desired outcome.
4. Developing decision pathways and decision points and beginning the journey along the chosen pathway.

The pathways approach can be simply incorporated into the CoastAdapt decision support tool C-CADS. The C-CADS process outlines how this can be done. Figure 3 summarises the key elements of a pathways approach at each of the steps of the C-CADS risk assessment and management framework. See Section 8 of Information Manual 4: Costs and Benefits for more details on the pathways approach to adaptation.