Should a region invest in higher dikes or make room for the river? Protect forests by suppressing fires or by reshaping the landscape? In ACCREU Deliverable 3.3, we looked at seven common adaptation decision types (ADTs) across very different sectors: flood risk, forestry and ecosystems, water-food-biodiversity, health and justice, finance, transport and supply chains, and national adaptation planning.
Building on the 15 ACCREU case studies and evidence from elsewhere in Europe, the aim was to derive practical insights for decisions that many European regions will face, and to outline generic adaptation pathways for each decision type. The evidence base ranges from a systematic review of over 150 flood risk appraisals to wildfire case studies, river basin modelling, heat-health plans and national adaptation cost assessments.
Although each review is very different, there are general lessons we can draw from them. To begin with, for each domain a limited set of distinct strategic directions can be identified. Making these explicit helps policymakers see the full range of options available, outside the most common (incremental) strategies. Based on the overview of adaptation strategies, we created a first overview of strategic directions within each domain (Table below).
| ADT | Strategic Directions |
| 1. Flood Risk | Keeping the water out; making space for water; reducing what is exposed; limiting impacts of flooding |
| 2. Forestry and ecosystems | Suppressing fires; fire prevention management in existing landscapes; transforming the landscape; reducing what is exposed (enabled by financing, incentives and capacity building strategies) |
| 3. Water-food-biodiversity | Increasing water-use efficiency; increasing or buffering supply; reducing or reshaping demand; reallocating between users |
| 4. Health and justice | Cooling the environment; reducing exposure of people and buildings; strengthening coping capacity; addressing structural drivers of vulnerability |
| 5. Finance and private sector | supporting public physical adaptation; using financial regulation to manage climate risk, involving private actors in spatial planning and insurance |
| 6. Transport and supply chains | Reducing the hazard around the network; making assets robust; keeping the network functioning; changing how the system operates (service levels, standards), with recovery as a temporal dimension across all |
| 7. Cross-cutting decisions | National planning groups actions by their nature (evidence and research, soft process-based, investment, mixed, green) and by attribution type (climate proofing, mixed adaptation, pure adaptation across all sectors and hazards). |
Moreover, several ADTs report that economic appraisal influences which strategies appear most attractive. For instance, several of the reviewed flood adaptation cases show that broadening the scope of a cost-benefit analysis changed the outcomes (Flood Risk). A narrow economic appraisal tends to favour grey measures over green or soft measures, which typically have more benefits than just flood protection. The Water-Food-Biodiversity review also highlights that environmental flows and biodiversity are typically harder to include in economic appraisals, which disadvantages measures that score well on those dimensions. The Transport & Supply Chains analysis shows the same: measures focused on redundancy are less likely to be favoured in a narrow economic appraisal tailored to analysing efficiency. Hence, the findings illustrate the importance of broadening the scope of economic appraisal.
Another lesson is that aggregate results can hide who bears the impacts/costs. A flood may barely affect financial stability at the level of the economy, yet be devastating for individual households (finance). Similarly, urban greening can reduce heat at the city level, but if it is concentrated in wealthier neighbourhoods, the distribution of risk may stay the same or even worsen (Health & Justice). Yet, such distributional effects are rarely assessed: Equity-weights are hardly used in flood adaptation appraisals, and the choice for utilitarian principles in appraisal is seldom made explicit (Transport & Supply chains). We therefore recommend to consider distributional effects early in adaptation planning, when options are still being defined, to broaden the range of measures that is considered. The Health & Justice review provides the most extensive analysis of distributional justice.
While some barriers to adaptation are specific to each theme, there are also overarching barriers to adaptation. Common barriers include limited financial resources, gaps in data and knowledge, limited awareness, fragmented governance, and political reluctance. Aligning policy instruments, institutional mandates, and budgets with where risks and responsibilities lie is a key next step.
Read the full deliverable here