Millennia-Long Progradation Turned into Coastal Erosion at Järve Coast of the Baltic Sea

Luik, K.; Suursaar, Ü.; Tõnisson, H.; Rivis, R.; Suuroja, S., and Vilumaa, K., 2024. Millennia-long progradation turned into coastal erosion at Järve coast of the Baltic Sea. In: Phillips, M.R.; Al-Naemi, S., and Duarte, C.M. (eds.), Coastlines under Global Change: Proceedings from the International Coastal Symposium (ICS) 2024 (Doha, Qatar). Journal of Coastal Research, Special Issue No. 113, pp. 235-239. Charlotte (North Carolina), ISSN 0749-0208. Throughout the Holocene, seacoasts of the Baltic Sea have experienced some profound changes and development shifts. The latest one, the turn of the uplift driven progradation into relative sea level (RSL) rise and associated coastal erosion, is studied at the south-facing Järve coast on Saaremaa Island, Estonia. Old cartographic and photographic material, results from coastal surveys (near-annual since the 1990s), LiDAR-based relief analysis, and met-ocean forcing data are used to reveal important turning points, driving mechanisms, and resulted effects in the coastal change. The RSL lowering, which has dominated on account of the geocentric land uplift component (∼2.2 mm/a) during most of the Late-Holocene, has turned into RSL rise in the 1930s–1940s. Over the past hundred years, sea level maxima from storms and their impacts have increased due to a combination of shifts in wind climate and sea-ice conditions. The duration of seasonal ice-cover at the Järve coast, as an average, has decreased from about 65 days to 25 days. As a result, the elevated Järve coastal barrier and scarped dune system, which build-up took 4000 years, is eroding now on its southern side. The recent change at Järve has been especially fast with the most notable coastal erosion events occurring during winter storms. The coastline has receded by around 50–80 m in the past 70 years, and the scarp and previously wide beach is losing sand through longshore sediment drift towards the east.