Adaptation effectiveness decreases with increasing warming

At present, we have a limited understanding of the effectiveness of adaptation to reduce risks in a warming world, as adaptation remains insufficiently addressed in climate impact projections. Where projections exist, these are mostly assessed in case study settings. Based on a meta-review of projections of adaptation, we assess the ability of different modelled water-related adaptation options to reduce climate risk at 1.5°C, 2°C, 3°C and 4°C of warming and show that the effectiveness of the assessed options decreases with increasing warming across all world regions and options. Our study focusses on those adaptation options most readily represented in sectoral climate impact models and thereby have direct relevance in making progress on better representing adaptation potentials within quantitative adaptation scenarios.