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 evidence on climate change adaptation in 199 coastal cities worldwide. Results 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, whereas 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 countries, 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 adaptation of coastal cities in the future.

The United Republic of Tanzania (Tanzania) is rich in freshwater resources and biodiversity. In this article, we highlight the importance of Tanzanian rivers and make a case for the conservation of the freshwater and terrestrial species that rely on these rivers. We provide an overview of current knowledge on Tanzanian rivers and discuss progress towards implementation of the National Water Policy (2002) and Water Management Act (2009), two legislative instruments that have motivated environmental flow assessments on at least six major rivers and offer legal backing for river conservation. We examine major challenges that pose significant threats to water security for river ecosystems and humans in Tanzania, among those: (1) human population growth, (2) agricultural expansion, (3) river flow alterations, (4) industrialization, (5) introduced species, and (6) climate change. We conclude by offering recommendations for future river conservation efforts in Tanzania.

Exposure to sea-level rise (SLR) and flooding will make some areas uninhabitable, and the increased demand for housing in safer areas may cause displacement through economic pressures. Anticipating such direct and indirect impacts of SLR is important for equitable adaptation policies. Here we build upon recent advances in flood exposure modeling and social vulnerability assessment to demonstrate a framework for estimating the direct and indirect impacts of SLR on mobility. Using two spatially distributed indicators of vulnerability and exposure, four specific modes of climate mobility are characterized: (1) minimally exposed to SLR (Stable), (2) directly exposed to SLR with capacity to relocate (Migrating), (3) indirectly exposed to SLR through economic pressures (Displaced), and (4) directly exposed to SLR without capacity to relocate (Trapped). We explore these dynamics within Miami-Dade County, USA, a metropolitan region with substantial social inequality and SLR exposure. Social vulnerability is estimated by cluster analysis using 13 social indicators at the census tract scale. Exposure is estimated under increasing SLR using a 1.5 m resolution compound flood hazard model accounting for inundation from high tides and rising groundwater and flooding from extreme precipitation and storm surge. Social vulnerability and exposure are intersected at the scale of residential buildings where exposed population is estimated by dasymetric methods. Under 1 m SLR, 56% of residents in areas of low flood hazard may experience displacement, whereas 26% of the population risks being trapped (19%) in or migrating (7%) from areas of high flood hazard, and concerns of depopulation and fiscal stress increase within at least 9 municipalities where 50% or more of their total population is exposed to flooding. As SLR increases from 1 to 2 m, the dominant flood driver shifts from precipitation to inundation, with population exposed to inundation rising from 2.8% to 54.7%. Understanding shifting geographies of flood risks and the potential for different modes of climate mobility can enable adaptation planning across household-to-regional scales.

Intensifying climate-related damages across the United States underscore the importance of climate-resilient housing, which requires coordination across diverse actors in the housing sector. Here, we assess the challenges and opportunities for reducing climate impacts on housing within U.S. coastal communities, based on 64 interviews with experts across housing-relevant public, private, and nonprofit sectors. We provide an overview of risk reduction actions being implemented as well as barriers and enablers to scaling up these responses. We find that current risk reduction actions focus on small-scale property-level adjustments or early-stage advocacy, though experts desire solutions that enable systems-wide reductions of climate–housing risks. Path dependencies, financing, and other entrenched multi-sectoral challenges currently limit resilient housing development. Experts perceive government interventions as essential in enabling resilient housing, and we find that government-led, multi-stakeholder collaborations have already catalyzed action. Understanding these cross-sectoral dynamics can inform actions and pathways to increase climate–housing resilience nationwide.