Global Warming

Flooding from high tides has doubled in the US in just 30 years

The frequency of coastal flooding from high tides has doubled in the US in just 30 years, with communities near shorelines warned that the next two years are set to be punctuated by particularly severe inundations, as ocean levels continue to rise amid serious global climate change concerns.

Last year there was an average of six flooding days per area across 98 coastal areas monitored by the National Oceanic and Atmospheric Administration (Noaa) – an all-time record. More than a quarter of these locations tied or broke their records for high tide flood days, the federal agency states in a new report.

The longer-term trend is even more certain, Noaa said, with melting glaciers, thermal expansion of sea water and altered ocean currents pushing the sea level steadily higher and causing further floods.

South Florida, where weather forecasts in some places now come with tidal warnings, and fish are a regular sight on flooded roads, is particularly vulnerable. The low-lying region sits on porous limestone, which pushes up floodwater from underground, and many communities are unable to easily retreat because they back on to the Everglades wetlands.

Globally, the seas have risen by an average of nearly three inches since 1992. Parts of the US coastline are unusually prone, with Noaa that the oceans could swell by more than eight feet by 2100.