Climate change-induced sea level rise has exacerbated coastal change putting millions of people at risk from coastal hazards, such as flooding and coastal erosion. Nature-based solutions have been recognised as an opportunity to simultaneously address the coastal hazard risks and achieve biodiversity goals. While such solutions are included in climate adaptation strategies, “hard” engineered solutions are still often preferred by those implementing the schemes. We sought to explore the diverse perspectives on UK coastal flood risk management among interested and/or affected groups by utilising the Q-methodology. We identified five perspectives: (1) The Pro-Green Practitioners; (2) The Future-Planning Relocators; (3) The Case-by-Case Thinkers; (4) The Cautious Practitioners and (5) The Climate Change Concerned. All five perspectives strongly valued the co-benefits of nature-based solutions and their role in coastal risk reduction. None of the perspectives prioritised hard-engineered solutions as the primary flood protection strategy in the UK, though they recognised their role in protecting essential infrastructure. The main disagreements between perspectives were (1) on the need for relocation strategies, and (2) whether nature-based solutions could cause social inequalities. The Q-methodology does not identify how prevalent such perspectives are, thus further research is needed to assess the social acceptance of nature-based solutions.

The latest IPCC report estimates that approximately 1 billion people will be at risk from coastal hazards in the near term due to coastal population increase, sea-level rise and other coastal changes. This will occur in a world that is changing rapidly due to climate change, ecosystem decline, human development and the projected transformations of the economy to meet the objectives of the Paris Agreement. In this context, social sciences provide a pivotal perspective to coastal adaptation, for example, while assessing barriers and opportunities across scales, from local to global. This scoping review explores how social sciences support coastal adaptation. We show that Political Sciences, Economics, Sociology and Geography are already supporting coastal adaptation. Yet, scientific fields such as legal sciences, psychology, history and archaeology as well as anthropology and ethnography are less developed in the context of coastal adaptation to sea-level rise. New research avenues could also integrate education, media and communication research and aim at truly interdisciplinary studies linking different branches of social sciences with coastal science and climate services. This effort could help moving from a coastal adaptation often focused on coastal engineering protection to a broader vision of coastal resilient development, also addressing the challenges of mitigation, sustainable development and coastal ecosystem decline.

Data were obtained from the literature to identify past changes in and the present status of the coastal carbon cycle. They indicate that marine coastal ecosystems driving the coastal carbon cycle cover, on average, 5.8% of the Earth’s surface and contributed 55.2% to carbon transport from the climate-active carbon cycle to the geological carbon cycle. The data suggest that humans not only increase the CO2 concentration in the atmosphere but also mitigate (and before 1860 even balanced) their CO2 emissions by increasing CO2 storage within marine coastal ecosystems. Soil degradation in response to the expansion and intensification of agriculture is assumed to be a key process driving the enhanced CO2 storage in marine coastal ecosystems because it increases the supply of lithogenic matter that is known to favour the burial of organic matter in sediments. After 1860, rising CO2 concentrations in the atmosphere indicate that enhanced CO2 emissions caused by land-use changes and the burning of fossil fuel disturbed what was a quasi-steady state before. Ecosystem restoration and the potential expansion of forest cover could mitigate the increase of atmospheric CO2 concentrations, but this carbon sink to the atmosphere is much too weak to represent an alternative to the reduction of CO2 emission in order to keep global warming below 1.5–2.°C. Although the contribution of benthic marine coastal ecosystems to the global CO2 uptake potential of ecosystem restoration is only around 6%, this could be significant given national carbon budgets. However, the impact on climate is still difficult to quantify because the associated effects on CH4 and N2O emissions have not been established. Addressing these uncertainties is one of the challenges faced by future research, as are related issues concerning estimates of carbon fluxes between the climate-active and the geological carbon cycle and the development of suitable methods to quantify changes in the CO2 uptake of pelagic ecosystems in the ocean.

Around 5000 BC, affluent village communities emerged along the South China Coast. Although traditionally regarded as ancestors of Austronesian migrants, whose farming economies expanded into the Asia-Pacific region, the new synthesis presented here shows that these coastal groups actually lived as hunter-gatherers and fishers, with evidence of socio-cultural complexity. Around c. 3000–2500 BC, this ‘first layer’ of hunter-gatherers witnessed the arrival of a ‘second layer’, associated with rice farming and Austronesian assemblages. This new synthesis positions global coastlines as centres of socio-economic and political complexity, long-distance contact and technological advancement.

In light of the urgent need for coastal adaptation policies and the impediments to their implementation, this article examines the early experience with coastal adaptation policies in the EU (in particular the Netherlands and the UK) and Australia, with a view to identifying the important features of an effective regulatory framework for coastal adaptation. We conclude that an integrated approach to coastal adaptation law is currently needed to lay the foundations for the required long-term strategy. Such an approach would establish processes by which adaptation objectives are agreed for each part of the coast, ensure land use planning that can accommodate future change and does not expose new communities to risk, integrate coastal adaptation with biodiversity and coastal zone policy, allocate regulatory responsibility in a way that promotes subsidiarity and consistency, and ensure that funds are available for future measures.