Are climate change adaptation strategies working? A call to expedite learning.

Evidence is lacking for what constitutes effective climate change adaptation to successfully conserve and steward ecosystems. Yet we urgently need this information to develop robust adaptation strategies to keep pace with unprecedented change, given our limited resources to do so. This includes not just understanding if a given strategy is effective in a single application, but perhaps more importantly if a given strategy has proven effective across sites where it has been applied, or has benefits only under certain sets of conditions. This learning across the field of adaptation is currently missing and is what is necessary for bringing adaptation to scale. We propose an approach that can guide adaptation efficacy testing under varying levels of baseline knowledge and ecosystem complexity. The approach includes clearly defining conservation goals and climate vulnerabilities, methodically collecting site and climate metrics to inform analysis of efficacy, and evaluating and communicating both positive and negative results in order to advance the adaptation field. Using this approach with meta-analyses and post-hoc testing can quickly scale efficacy testing in a meaningful way. Furthermore, explicitly incorporating efficacy testing into adaptation processes can support the growth of the adaptation field and spark creative, adaptive management approaches that will increase the likelihood of reducing climate change vulnerability.