Science and Tech

Coastal flooding due to higher than normal tides caused by global warming

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Sudden increases in water level in coastal areas can be caused by high tide and/or by a storm surge (rise in sea water caused by the wind of a storm and which can flood coastal land). In the case of high tide, as it is already known in advance, there are usually no problems. However, global warming is leading to a rise in sea level and other effects that increase the cases of coastal flooding without the need for a storm.

For example, in the United States, three communities, on the Atlantic and Pacific coasts, suffered record flooding from high tides last year. Unfortunately, according to NOAA (National Oceanic and Atmospheric Administration) forecasts, this trend will continue through 2023 and beyond, unless such flood protection infrastructures are improved.

NOAA has documented changes in coastal high-tide flooding patterns from May 2021 through April 2022 at 97 of its stations along the U.S. coastline for tide gauges.

High tide flooding is becoming more frequent due to decades of sea level rise and other causes. They occur when tides reach 50 to 60 centimeters above the daily mean high tide and water begins to spill onto streets or gush out of storm drains.

Coastal flooding like this, occurring without a storm, will become more frequent due to global climate change. (Photo: NOAA)

As sea levels continue to rise, damaging flooding, which decades ago only occurred during a storm, will occur more regularly, such as during a full moon or with a favorable change in prevailing winds or currents. (Font: NCYT by Amazings)

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