An operationalize classification of Nature Based Solutions

Description

A classification is not an academic exercise. Practitioners selecting measures need to know what a given intervention is, what it does, and what it depends on — and the answers change with the degree to which people have shaped the system. This tool classifies Nature Based Solutions for water-related hazards along the axis of human intervention, from measures that protect and manage existing ecosystems through to measures that create new ones.

Layered onto that axis is the information that has to be considered before a measure is selected. Two aspects in particular are regularly left out of shortlists. The first is the potential undesired effect of a solution arising from malfunction or from poor ecosystem management. The second is the effect of climate change on the solution's own performance: a measure dimensioned for today's rainfall distribution may be a liability under tomorrow's.

The framework is presented as a matrix. Reading a candidate measure across it produces a portfolio rather than a single answer, and makes the criteria for selection explicit enough to be argued with.

Applications to decision making in the insurance sector

Insurers and reinsurers are exposed to the long tail of a measure's performance, not to its design intent. The classification's emphasis on malfunction, on management quality and on performance under changed climate is the part of an NBS appraisal that most closely matches what a risk carrier needs to price.

It also supports portfolio thinking. Where a strategy relies on several measures of different types and maturity, the matrix shows at a glance where the performance risk is concentrated.

Added value of this modelling approach

It gives a common vocabulary. Discussions about Nature Based Solutions bring together ecologists, engineers, planners and financiers who use the same words for different things; a shared classification removes a large part of the misunderstanding before it happens.

It also forces the two neglected questions — malfunction and climate performance — into the room at the point where options are still being generated, rather than at the point where a preferred option is already being defended.

What decision can be improved with this modelling approach

Shortlisting measures for a water risk strategy; assessing the sustainability of a measure over its service life; identifying where a portfolio depends too heavily on a single type of intervention; and justifying to an appraisal body why a particular NBS was selected over its alternatives.