Abstract

Evaluating the effectiveness of adaptation policies and actions is important to advance the scale and scope of climate risk reduction. The goal of this WASP Science for-Adaptation Policy Brief (SAPB) is to enhance the understanding of the effectiveness of climate adaptation by elucidating the dynamic framing for adaptation policy and action, identifying areas where approaches for ensuring adaptation effectiveness have advanced, highlighting adaptation effectiveness in international and national policymaking and measuring adaptation effectiveness of actions on the ground.

The overall objective of adaptation is to reduce climate change vulnerability, hazards and exposure (through enhancing adaptive capacity), resulting in reducing climate change risks. Adaptation effectiveness refers to the extent to which policies and actions reduce present and future climate risks. Measuring effectiveness is an important component of successful adaptation. Recent understanding has highlighted adaptation aims related to ambition, feasibility, equity, and justice while emphasizing the need to ensure that adaptation actions do not result in negative unintended consequences. The IPCC AR6 highlights the need for adaptation solutions (i.e., that are effective over time and space) that are ambitious, feasible, and equitable, conforming to principles of justice.

Key Messages:

• Evaluating the effectiveness of adaptation policies and actions is key to understanding whether they have reduced climate risks and achieved other intended outcomes. The goals are to ensure that adaptation is adequate to address climate risks, do not foster negative unintended consequences over space and time, and inform adaptation financing.
• Adaptation effectiveness is vital to inform both national and local-level adaptation actions as well as progress towards the Global Goal on Adaptation and the UNFCCC global stocktake (GST).
• However, despite the urgency to implement effective adaptation at scale, understanding adaptation effectiveness is still evolving and the development of ways to measure it is ongoing. The diverse contexts and adaptation interventions make it challenging to understand and operationalize adaptation effectiveness. Specifically, measuring change requires a definition of the baseline conditions and measurement of change against that baseline. Attributing outcomes to investments is also challenging.
• Determining the effectiveness of adaptation policy and action needs to take account of the dynamic nature of adaptation. Regular re-evaluation of adaptation policies and actions over time can help to enhance adaptation effectiveness overall.
• Adaptation interventions need to be assessed for their potential effectiveness (ex-ante) and measure actual effectiveness (ex-post) using a set of metrics identified based on specific criteria. Monitoring and evaluation during implementation helps to ensure climate risk reduction.
• Useful metrics for effectiveness in adaptation policy and action include quantitative and qualitative measures for risk and vulnerability reduction. Qualitative indicators include composite measures of ambition, feasibility, and equity/justice.