Decision-making for an uncertain future

Dr Lisa Horrocks Climate Change

Lisa Horrocks, Principal Climate Resilience Consultant at Mott MacDonald, comments on some initiatives tackling the issue around long term climate change solutions. 

Water supply system in Armenia.

Water supply system in Armenia.

Wherever we are in the world, economic development requires us to take decisions which either have short or very long lifetimes.

Fig: Illustrative examples of decision lifetimes

Long lifetime decisions can be extremely costly and risky, especially with shifting baselines. This is the situation with climate change. Uncertainty looms over long-term investments that will need to overcome unknown future challenges posed by a changing climate.

Fig: Example scenarios of global temperature change (from IPCC AR5)


Incremental adaptation can be an appropriate strategy for short-term decisions. However, transformative adaptation (much larger systemic changes) might be necessary to cope with the higher-end climate scenarios possible by 2100. So, how do we set about taking decisions that could lead to transformation with an uncertain future?

A Systematic Approach to Decision-Making

A systematic approach can identify categories of decisions for which different kinds of risk management tools are appropriate. There are three significant factors:

  • Decision lifetime
  • The nature of the climate change uncertainty
  • The preferred adaptation responses under different future scenarios

Each combination of these three factors will require a different approach to risk management and appropriate risk reduction tactics. And it turns out that many decisions aren’t that complex after all.

However, there are some categories that are trickier. For example, as is often the case with precipitation projections, situations arise where there is uncertainty over the direction and effect of climate change and where different responses under different futures are anticipated. This represents a set of adaptation decisions where transformative options are likely to be relevant responses, and where risk-hedging and delaying action may also be needed on the way to resilience.

Decision-making under uncertainty in practice

There are a growing number of examples where this kind of decision-making is being introduced in practice.

The World Bank’s Climate Change Decision Tree Framework (DTF) provides a cost-effective and scientifically defensible method for enhancing the robustness of a project to climate change. It is a bottom-up approach, which starts with a quick assessment of overall system vulnerability to many potential climate impacts, followed by detailed analyses of more problematic aspects. It then moves on to the identification of resilience solutions. The initial development of the DTF, and its subsequent refinement, have involved extensive collaboration between World Bank staff, researchers, engineers, infrastructure project developers and investors, as well as utility companies, among others.

Fig: World Bank Climate Change Decision Tree

Fig: World Bank Climate Change Decision Tree

Bridging the gap

The DTF is a step forward, but practitioners still find it hard to use climate information in project planning and design. To help bridge this gap, Mott MacDonald has been working with the World Bank. In collaboration with global hydropower and dam associations and hydropower utility companies they provide guidelines that incorporate the DTF into common processes used in the hydropower sector.

The guidelines will provide practical and workable ‘international good practices’ for incorporating climate change resilience and disaster risk management into hydropower project appraisal, design, rehabilitation, construction and operation. The World Bank intends to test the guidelines in pilot projects around the world to collect feedback on the practical use.

We are beginning to see real examples of long lifetime, climate-sensitive schemes incorporating climate risk and uncertainty, and providing resilience for the communities and stakeholders they serve.

Another good example comes from the urban water supply and sanitation sector. In a review of their master plan, SEDAPAL, the water authority for Lima in Peru, worked with the World Bank to apply the decision tree approach and linked methods for decision-making under deep uncertainty.

Fig: Decision tree developed for SEDAPAL water resource planning, Lima, Peru

Fig: Decision tree developed for SEDAPAL water resource planning, Lima, Peru

On the way to resilience

Conceptual frameworks can help reduce the complexity inherent in resilience decision-making. They also assist infrastructure planners to think longer-term when making significant decisions today.  However, even with excellent frameworks, project managers still find it hard to use climate science in their planning and decision-making. Support is needed to integrate climate information into commonly used tools and processes, and collaboration between different stakeholders is essential on the way to resilience.


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