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2019-05-03. As Sea Levels Rise, Expect More Floods.

posted May 12, 2019, 7:39 AM by Alan Gould
By Aaron Sidder, Eos/AGU. [https://eos.org/research-spotlights/as-sea-levels-rise-expect-more-floods] For GSS Climate Change chapter 8. Excerpt: The global mean sea level currently measures 77 millimeters higher than in 1993 when the satellite sea level record began. According to the Fifth Assessment Report from the United Nations’ Intergovernmental Panel on Climate Change, the global mean sea level is expected to continue rising throughout the 21st century. With 126 million Americans—40% of the total population of the United States—living along the coasts, rising seas could cause widespread property and socioeconomic damage in the coming century. Coastal communities require adaptation and mitigation strategies for both frequent, minor flooding and extreme, high-water events (i.e., major flooding). ...One challenge of strategic planning is that many statistical models struggle to simultaneously characterize both minor and major flood events resulting from rising sea levels. To address this challenge, Ghanbari et al. [https://doi.org/10.1029/2018EF001089] developed a new model to facilitate a nonstationary analysis of coastal flood frequency. ...The study incorporated data from 68 tidal monitoring locations around the country to estimate the type and frequency of flooding throughout the contiguous United States.... The study also reports on flood exposure for 20 coastal cities. The authors found that, generally, flood return periods shorten as sea level rises. For example, if sea levels climb by 15.24 centimeters, a 500-year flood will become a 10-year flood along the Pacific coasts. ...If sea levels rise by approximately 61 centimeters, the authors report that the majority of coastal communities will experience major floods multiple times (2–6 days) and more than 150 days of minor flooding per year....