European Commission, Joint Research Centre (JRC), Directorate for Space Security and Migration, Via Enrico Fermi 2749, 21027, Ispra, Italy.
Department of Marine Sciences, University of the Aegean, Mitilene, Lesbos, Greece.
Sci Rep. 2018 Aug 27;8(1):12876. doi: 10.1038/s41598-018-30904-w.
Changes in coastal morphology have broad consequences for the sustainability of coastal communities, structures and ecosystems. Although coasts are monitored locally in many places, understanding long-term changes at a global scale remains a challenge. Here we present a global and consistent evaluation of coastal morphodynamics over 32 years (1984-2015) based on satellite observations. Land losses and gains were estimated from the changes in water presence along more than 2 million virtual transects. We find that the overall surface of eroded land is about 28,000 km, twice the surface of gained land, and that often the extent of erosion and accretion is in the order of km. Anthropogenic factors clearly emerge as the dominant driver of change, both as planned exploitation of coastal resources, such as building coastal structures, and as unforeseen side effects of human activities, for example the installment of dams, irrigation systems and structures that modify the flux of sediments, or the clearing of coastal ecosystems, such as mangrove forests. Another important driver is the occurrence of natural disasters such as tsunamis and extreme storms. The observed global trend in coastal erosion could be enhanced by Sea Level Rise and more frequent extreme events under a changing climate.
海岸形态的变化对沿海社区、建筑物和生态系统的可持续性有着广泛的影响。尽管在许多地方都对海岸进行了局部监测，但要了解全球范围内的长期变化仍然是一个挑战。在这里，我们基于卫星观测，呈现了一个长达 32 年（1984-2015 年）的全球一致的海岸形态动力变化评估。通过超过 200 万条虚拟横剖线上的水体变化，我们估算了陆地的损失和增加。我们发现，侵蚀陆地的总面积约为 28000 平方公里，是获得陆地面积的两倍，而且侵蚀和堆积的范围通常在几公里的数量级。人为因素显然是变化的主要驱动因素，包括对沿海资源的有计划开发，如建造沿海建筑物，以及人类活动的意外副作用，例如大坝、灌溉系统和改变沉积物通量的建筑物的安装，或者沿海生态系统，如红树林的清除。另一个重要的驱动因素是自然灾害的发生，如海啸和极端风暴。在气候变化下，海平面上升和更频繁的极端事件可能会加剧观察到的全球海岸侵蚀趋势。
