Progress and gaps in climate change adaptation in coastal cities across the globe

Coastal cities are at the frontlines of climate change impacts, resulting in an urgent need for substantial adaptation. To understand whether and to what extent cities are on track to prepare for climate risks, this paper systematically assesses the academic literature to evaluate climate change adaptation in 199 coastal cities worldwide. We show that adaptation in coastal cities is rather slow, of narrow scope, and not transformative. Adaptation measures are predominantly designed based on past and current, rather than future, patterns in hazards, exposure, and vulnerability. City governments, particularly in high-income countries, are more likely to implement institutional and infrastructural responses, while coastal cities in lower-middle income countries often rely on households to implement behavioral adaptation. There is comparatively little published knowledge on coastal urban adaptation in low and middle income economies and regarding particular adaptation types such as ecosystem-based adaptation. These insights make an important contribution for tracking adaptation progress globally and help to identify entry points for improving adaption of coastal cities in the future

A systematic global stocktake of evidence on human adaptation to climate change

Assessing global progress on human adaptation to climate change is an urgent priority. Although the literature on adaptation to climate change is rapidly expanding, little is known about the actual extent of implementation. We systematically screened >48,000 articles using machine learning methods and a global network of 126 researchers. Our synthesis of the resulting 1,682 articles presents a systematic and comprehensive global stocktake of implemented human adaptation to climate change. Documented adaptations were largely fragmented, local and incremental, with limited evidence of transformational adaptation and negligible evidence of risk reduction outcomes. We identify eight priorities for global adaptation research: assess the effectiveness of adaptation responses, enhance the understanding of limits to adaptation, enable individuals and civil society to adapt, include missing places, scholars and scholarship, understand private sector responses, improve methods for synthesizing different forms of evidence, assess the adaptation at different temperature thresholds, and improve the inclusion of timescale and the dynamics of responses