Shoreline communities may be inundated in the next two years as ocean levels rise amid serious climate change concerns
Wed 6 Jun 2018
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.
Known as “sunny day flooding”, these events swamp streets and homes with water simply from the incoming tide, without the aid of a storm. Noaa said that in 2017 areas across the US north-east and Gulf of Mexico were worst hit, with Boston, Massachusetts, and Atlantic City, New Jersey, both experiencing 22 days of flooding, while Galveston, in Texas, was soaked on 18 different days.
Noaa warned that cyclical climatic conditions during 2018 and 2019 “may result in higher than expected flood frequencies” in around half of the coastal sites it measures.
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.
“Breaking of annual flood records is to be expected next year and for decades to come as sea levels rise, and likely at an accelerated rate,” the report states. “Though year-to-year and regional variability exists, the underlying trend is quite clear: due to sea level rise, the national average frequency of high tide flooding is double what it was 30 years ago.”
The Noaa report is “comprehensive” and “clearly illustrates the increasing problems along our coastlines”, said Ben Horton, a sea level rise expert at Rutgers University. “There is flooding on all our coastlines, places where people live and work. There needs to be a national response to that.”
Last year was marked by three high-profile hurricanes that pummelled the US, triggering flooding that resulted in dozens of deaths and billions of dollars in damage. Scientists have found that warming temperatures, driven by human activity, is making hurricanes stronger, but it is also exacerbating more chronic nuisance flooding events by pushing up the level of the ocean.