How can I support NBS planning and decision-making under deep uncertainty?

Overview

Decisions about Nature Based Solutions are usually taken before the evidence is complete. The climate projection the design depends on will be revised, the land use assumptions will change, and the costs will not be known to the precision the appraisal format asks for. Adaptive planning is the approach that makes the decision defensible anyway, by treating the plan as something that is revised as evidence arrives rather than fixed at the moment of approval.

What the approach involves

Adaptive planning begins by identifying the decisions that are genuinely difficult to reverse and separating them from those that can be adjusted later. The irreversible commitments are the ones that have to be robust across the range of futures considered; the reversible ones can be sequenced, with the later steps made contingent on what is learned. This reordering frequently changes the plan substantially, because measures that looked essential when everything was decided at once turn out to be optional when they can wait.

It then sets out what would have to be observed for the plan to change course, and how that observation will be made. A plan that cannot state its own trigger conditions is not adaptive, whatever it is called. The monitoring arrangements — including low-cost sensor networks where the area is large and the budget is not — are therefore part of the plan rather than an addition to it.

The approach is applied through a structured workshop protocol, in which stakeholders work through the planning cycle together: establishing the problem, identifying and appraising options, selecting, implementing, and reviewing. The protocol specifies the activities for each workshop and the steps in the framework of analysis, so that the process produces comparable material across different sites and does not depend on the skill of a particular facilitator.

Why it suits Nature Based Solutions

Nature Based Solutions are long-lived, they depend on processes that respond slowly, and their performance is affected by a changing climate in ways that are genuinely uncertain. They are also modular: a catchment can be treated in stages, and each stage delivers something. That combination makes them a natural fit for an adaptive approach, and it allows a decision to be taken now on the strength of the evidence available now, without pretending that the uncertainty has been removed.