ИСТИНА

Sea ice and perennially frozen ground are key constituents of permafrost coastal systems, and their presence is the primary difference between temperate and high-latitude coastal processes. These systems are some of the most rapidly changing landscapes on Earth and, in the Arctic, are representative of the challenges being faced at the intersection between natural and anthropogenic systems. Permafrost thaw, in combination with increasing sea level and changing sea-ice cover, exposes Arctic coastal and nearshore areas to rapid environmental and social changes. Based on decadal timescales, observations in the Arctic indicate an increase in permafrost coastal bluff erosion since the early 2000s and an increase in storm surge flooding of low-lying permafrost lowlands. However, circum-Arctic observations remain limited and the factors responsible for the apparent increase in Arctic coastal dynamics are poorly constrained. A better understanding of permafrost coastal systems and how they are responding to changes in the Arctic is important since a high proportion of Arctic residents live on or near coastlines, and many derive their livelihood from terrestrial and nearshore marine resources. An expanding industrial, scientific, and commercial presence in the Arctic Ocean will require advanced knowledge about permafrost coastlines as terrestrial access points. An international network focused on permafrost coastal systems in transition is needed since the issues involved span political, cultural, geographical, and disciplinary borders. An integrative network focused on permafrost coastal systems is required to realize and address the scale and complexity of the processes, dynamics, and responses of this system to physical, ecological, and social change. A primary focus of such an effort would be guided by the fact that the issues and impacts associated with permafrost coastal systems in transition are far greater than any single institution or discipline is capable of addressing alone. Future permafrost coastal system dynamics will challenge conventional wisdom as the system enters a new state impacting human decision making and adaptation planning, impacts to cultural heritage resources, and likely resulting in unforeseen challenges across the Arctic.