Coastal erosion

Tunnel-like structures formed by erosion in Jinshitan Coastal National Geopark, Dalian, Liaoning Province, China

Coastal erosion is the loss or displacement of land, or the long-term removal of sediment and rocks along the coastline due to the action of waves, currents, tides, wind-driven water, waterborne ice, or other impacts of storms.^[1]^[2] The landward retreat of the shoreline can be measured and described over a temporal scale of tides, seasons, and other short-term cyclic processes.^[3] Coastal erosion may be caused by hydraulic action, abrasion, impact and corrosion by wind and water, and other forces, natural or unnatural.^[3]

On non-rocky coasts, coastal erosion results in rock formations in areas where the coastline contains rock layers or fracture zones with varying resistance to erosion. Softer areas become eroded much faster than harder ones, which typically result in landforms such as tunnels, bridges, columns, and pillars. Over time the coast generally evens out. The softer areas fill up with sediment eroded from hard areas, and rock formations are eroded away.^[4] Also erosion commonly happens in areas where there are strong winds, loose sand, and soft rocks. The blowing of millions of sharp sand grains creates a sandblasting effect. This effect helps to erode, smooth and polish rocks. The definition of erosion is grinding and wearing away of rock surfaces through the mechanical action of other rock or sand particles.

According to the IPCC, sea level rise caused by climate change will increase coastal erosion worldwide, significantly changing the coasts and low-lying coastal areas.^[5]

^ Ueberman, A.S.; O'Neill Jr, C.R. (1988). Vegetation use in coastal ecosystems (PDF). Information Bulletin. Vol. 198. Cornell Cooperative Extension, Cornell University.
^ Gibb, J.G. (1978). "Rates of coastal erosion and accretion in New Zealand" (PDF). New Zealand Journal of Marine and Freshwater Research. 12 (4): 429–456. doi:10.1080/00288330.1978.9515770.
^ ^a ^b Stephenson, W. (2013). "Coastal Erosion". In Bobrowsky, P.T. (ed.). Encyclopedia of Natural Hazards. Springer. pp. 94–96. ISBN 978-9048186990.
^ Valvo, Lisa M.; Murray, A. Brad; Ashton, Andrew (1 June 2006). "How does underlying geology affect coastline change? An initial modeling investigation". Journal of Geophysical Research: Earth Surface. 111 (F2): F02025. Bibcode:2006JGRF..111.2025V. doi:10.1029/2005JF000340.
^ Wang, P. P.; Losada, I. J.; Gattuso, J.-P.; Hinkel, J.; et al. (2014). "Chapter 5: Coastal Systems and Low-Lying Areas" (PDF). IPCC AR5 WG2 A 2014. pp. 361–409.

[UebermanOthers1988a-1] Ueberman, A.S.; O'Neill Jr, C.R. (1988). Vegetation use in coastal ecosystems (PDF). Information Bulletin. Vol. 198. Cornell Cooperative Extension, Cornell University.

[Gibb1978a-2] Gibb, J.G. (1978). "Rates of coastal erosion and accretion in New Zealand" (PDF). New Zealand Journal of Marine and Freshwater Research. 12 (4): 429–456. doi:10.1080/00288330.1978.9515770.

[Stepenson2013a-3] Stephenson, W. (2013). "Coastal Erosion". In Bobrowsky, P.T. (ed.). Encyclopedia of Natural Hazards. Springer. pp. 94–96. ISBN 978-9048186990.

[4] Valvo, Lisa M.; Murray, A. Brad; Ashton, Andrew (1 June 2006). "How does underlying geology affect coastline change? An initial modeling investigation". Journal of Geophysical Research: Earth Surface. 111 (F2): F02025. Bibcode:2006JGRF..111.2025V. doi:10.1029/2005JF000340.

[5] Wang, P. P.; Losada, I. J.; Gattuso, J.-P.; Hinkel, J.; et al. (2014). "Chapter 5: Coastal Systems and Low-Lying Areas" (PDF). IPCC AR5 WG2 A 2014. pp. 361–409.

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