Extreme weather events are becoming increasingly common, and disastrous floods, counting among them, are threatening the U.S. coastal counties more than before.
Typically, these events are blamed on climate change. And while this thesis is not incorrect, it fails to pinpoint which aspects of climate change are underscoring these events and their interplay.
A new study, conducted by a joint research team from the University of South Florida College of Marine Science in partnership with the University of Siegen, Germany tried to identify what are the key factors that threaten the U.S. coastal cities.
Their findings indicate rather dire future prospects: U.S. cities could be experiencing more disaster-yielding flooding due to a triple factor combination: rising sea levels, storm surge, as well as heavy rainfall. When heavy rainfall and storm surge happen almost simultaneously, the result is called compound flooding.
From New York to San Francisco to Galveston and Boston, coastal areas are most at risk of compound flooding compared to the rest of the U.S.
According to lead author of the study, Thomas Wahl, postdoctoral student at the University of South Florida, extreme flooding would heavily the approximately 40 percent U.S. citizens living in coastal areas.
“Flooding can have devastating impacts for these low-dying, densely populated and heavily developed regions and have wide-ranging social, economic and environmental consequences”,
stated Thomas Wahl.
In order to identify the triple punch factors and how they intertwine to give rise to serious concerns, the research team perused historical data ranging from the the early 20th century for some sites of concern, to present.
Particularly, the focus of the study was set on those areas that have never been researched before. The team asked how often did compound flooding occur in the U.S. coastal regions. Here, heavy development has taken lead in the past decades and population increased considerably.
And they received an answer. The historical data comprised information on heavy precipitation events, storm surge, tidal gauges, as well as hurricane tracks. Overall, the cities located along the Gulf coast and the Atlantic coast are at higher risk of compound flooding than cities located on the Pacific coast.
Nonetheless, that is not to downplay the impact of compound flooding in one region or the other. For the Atlantic and the Gulf coasts, the researchers found that there is a silverning pattern of heavy precipitation linked with storm surge in these two regions of the U.S. coast. Also, that they tend to repeat more often in the present.
If there is more to add to the disaster recipe, that is the rising sea level. Rising sea level translates into rising storm surge levels and the blocking of rainwater drainage.
The study features in the Nature Climate Change journal. According to the researchers, this starting point in understanding the risks that coastal zones, particularly the Gulf and Atlantic coasts, are being submitted to is real and that thorough planning is needed to avoid disasters.
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