Climate Change and Anthropogenic Impact on Coastal Environments

Coastal-transitional areas, including delta plains, strandplains, lagoons, embayments, salt marshes, and mangroves, are some of the most valuable global resources in terms of both socioeconomic interest and cultural–natural heritage. However, these areas, placed at the border between land and sea, are extremely sensitive to the combined effect of several natural and anthropogenic factors, resulting in them inevitably being at the forefront of the threat of global change. In this respect, approximately 28,000 km2 of global coastline was eroded between 1984 and 2015, about twice as much as that formed by accumulation processes [1]. Besides coastal erosion and loss of territory, severe impacts on environments and ecosystems are ascribable to the accumulation of anthropogenic debris, contaminants, and algal masses (e.g., [2,3,4,5,6]). According to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change-IPCC, by 2100 the health of coastal zones will worsen as a result of the gradual rise in sea-level and due to the possible increase in frequency and intensity of extreme events. Both phenomena are related to global warming that, in turn, is very likely connected with the use of fossil fuels and the increased human pressure on the Earth [7]. Unfortunately, the IPCC projections appear too optimistic since the global sea-level is likely to rise considerably (up to 1.35 m) and more rapidly than what has been forecast so far. Indeed current predictions suffer from the limited amount of information concerning changes in ice-sheet volumes and, specifically, data on the melt-off rate of Antarctica are considered crucial for robust model testing and analysis [8]. All these elements, contextualized into the natural dynamic equilibrium of coasts, may put at risk the future of many human lives, cities, and services, as hundreds of millions of people currently live and take advantage of the coastal zone (e.g., [9,10]). The urgent need for good practices, aimed at the preservation and sustainable exploitation of natural resources, has increased the interest of the scientific community in the complex dynamics and resilience strategies of low-lying coastal-delta plains and rocky coastal sectors. In this regard, the high sensitivity of coastal-transitional environments to climate-relative sea level (RSL) oscillations and anthropogenic activities, operating at various timescales (from millennial to sub-centennial), makes them exceptional geological archives storing critical information about present and past processes alike. This Special Issue focuses on three main aspects of coastal-transitional systems, namely, complexity, vulnerability, and sensitivity; underlining the key role played by highly integrated multidisciplinary approaches to unraveling the records of the present and the past. This Issue aims to illustrate a set of recent advances in field and remote sensing observations, laboratory techniques, numerical modelling, and statistical analyses applied to the quantitative monitoring of coastal areas and the reconstruction of past landscape dynamics under changing climate-RSL conditions.