New research highlights flood risks from sea-level rise

Recent scientific studies on the impacts of sea-level rise can help cities and businesses in coastal areas strengthen their climate resilience planning.  

Coastal flooding is expected to be a particularly costly climate impact. As the seas rise, U.S. cities from Miami to Atlantic City, New Jersey, now routinely deal with tidal flooding, also called nuisance flooding or sunny day flooding. But higher sea levels can also magnify flooding from more rare major storms like hurricanes.

Researchers at Princeton and Rutgers recently took into account the fact that coastal cities face this combination of small (high-probability) and large (low-probability) flooding events. They took observations from the National Oceanic and Atmospheric Administration’s (NOAA) tide gauges and used statistical techniques to measure the occurrence of historically low- and high-probability events across coastal locations. They then used sea-level rise projections to understand how the frequency of low- and high-probability events would change at each location.

The key insight from this study is that sea-level rise will have a different impact on flooding patterns in different regions of the country. Charleston, South Carolina, will see a larger increase in moderate floods than in severe floods (though both types of floods will increase), while Seattle will see the opposite pattern.

The study also demonstrates that flood frequencies will increase dramatically in many coastal areas by 2050. The blue and green dots in the maps below show the places where flood frequencies will increase by hundreds or even thousands of times from today (Alaska and Hawaii were also modeled in the study, but not shown in this map. The full dataset is here).

Source: Princeton University, 2017.

It’s no wonder, then, that cities and businesses across the country are taking steps to prepare for flooding and other climate change risks. We continue to urge them to work together to find the options that work best for the community overall.