Uncertainty and shifting baselines

The uncertainty surrounding climate change impacts, including the frequency and intensity of extreme events and the long-term repercussions of climate change effects, has to be considered when designing evaluation frameworks for adaptation projects. Adaptation takes place against a backdrop of evolving climate hazards, which may become more frequent and severe, resulting in climate-related losses, or become less pronounced over the timescale of a project. The impacts of adaptation projects must be assessed against changing hazard profiles, meaning that it is not necessarily sufficient to compare losses or damages before and after adaptation interventions. Where trends in climate hazards occur over periods during which assessment of project impacts are taking place, indicators of loss or damage must be ‘normalized’ to account for changing hazards. Evaluation methodologies based on the before-after approach assume stability in the underlying conditions of the baseline. However, in relation to adaption project implemented against the backdrop of changing climatic conditions, the baseline shifts in uncertain and emerging ways and the validity of the comparison of the post-intervention effect to the pre-intervention baseline does not present a clear indication of the effect of the adaptation project.