Coastal cities in the United States could experience an average of 30 days of flooding each year due to sea level rise driven by global warming, the National Oceanic and Atmospheric Administration (NOAA) warns. These levels could be reached by the year 2050, according to a new report.
The agency has established "tipping points" for sea-level related flooding, when nuisance flooding - one to two feet above local high tide - is experienced by a region 30 or more times in a year.
Researchers developed a climate model utilizing a projected sea level rise of between 18 inches and four feet, similar to estimates accepted by the Intergovernmental Panel for Climate Change (IPCC). The NOAA model also accounted for land development and urbanization. Projections were based on data collected from NOAA tidal stations with 50 years or more of historical data.
In Louisiana and some other areas, human settlement of land, has resulted in the ground sinking, in a process called subsidence. This can aggravate flooding concerns in regions near large bodies of water.
"Coastal communities are beginning to experience sunny-day nuisance or urban flooding, much more so than in decades past. This is due to sea level rise. Unfortunately, once impacts are noticed, they will become commonplace rather quickly," William Sweet, oceanographer at the Center for Operational Oceanographic Products and Services (CO-OPS) at NOAA, said.
According to the study, most of the areas examined could experience near-daily flooding, requiring a widespread, costly response to prevent widespread damage. Researchers hope their study could help urban planners prepare for more frequent, and severe, storms driven by global warming.
"Communities across the country become increasingly vulnerable to water inundation and flooding, effective risk management is going to become more heavily reliant on environmental data and analysis," Holly Bamford, acting assistant secretary for conservation and management at NOAA, stated in a press release.
Nuisance storms usually result in damage to communities, but rarely cost human lives.
Boston, Philadelphia, New York City, Baltimore, Wilmington, and Norfolk were found to be in the greatest need of urban planning to offset damage from more frequent nuisance flooding in the east. San Francisco, San Diego, Galveston Bay and Port Isabel, Texas were also named as potential danger spots in the study.
Many climatologists are currently predicting severe damage from flooding by the year 2100, but this new research shows nuisance flooding could fuel severe problems by the middle of the century.
Global warming-related flooding and the development of urban tipping points were detailed in the journal Earth's Future, published by the American Geophysical Union.
