Princeton, NJ, March 14, 2012 Sea
level rise due to global warming has already doubled the annual
risk of coastal flooding of historic proportions across widespread
areas of the United States, according to a new report from Climate
By 2030, many locations are likely to see storm surges combining
with sea level rise to raise waters at least 4 feet above the local
high-tide line. Nearly 5 million U.S. residents live in 2.6 million
homes on land below this level. More than 6 million people live on
land below 5 feet; by 2050, the study projects that widespread
areas will experience coastal floods exceeding this higher
"Escalating floods from sea level rise
will affect millions of people, and threaten countless billions of
dollars of damage to buildings and infrastructure." Dr. Ben
Strauss of Climate Central.
Titled "Surging Seas", the report is the first to
analyze how sea level rise caused by global warming is compounding
the risk from storm surges throughout the coastal contiguous
It is also first to generate local and national estimates of the
land, housing and population in vulnerable low-lying areas, and
associate this information with flood risk timelines.
The Surging Seas website includes a searchable, interactive online map that zooms down to neighborhood
level, and shows risk zones and statistics for 3,000 coastal towns,
cities, counties and states affected up to 10 feet above the high
In 285 municipalities, more than half the population lives below
the 4-foot mark. One hundred and six of these places are in Florida, 65 are in Louisiana, and ten or more are in New York (13), New Jersey (22), Maryland (14), Virginia (10) and North Carolina (22). In 676 towns and cities
spread across every coastal state in the lower 48 except Maine and Pennsylvania, more than 10% of the population
lives below the 4-foot mark.
Tidal gauge records show that the sea has already risen 8 inches
globally during the last century, and projections point to a steep
acceleration. "Sea level rise is not some distant problem that we
can just let our children deal with. The risks are imminent and
serious," said report lead author Dr. Ben Strauss of Climate
"Just a small amount of sea level rise, including what we may
well see within the next 20 years, can turn yesterday's manageable
flood into tomorrow's potential disaster. Global warming is already
making coastal floods more common and damaging."
In addition to the Surging Seas report and website, Climate
Central is releasing fact sheets laying out the risks for each
coastal state. Staff scientists (Ben Strauss, Claudia Tebaldi,
Remik Ziemlinski) have also authored two peer-reviewed studies
being published March 15th in the scientific journal Environmental Research
Letters, with co-authors at the University of Arizona
(Jeremy Weiss, Jonathan Overpeck) and the National Oceanic and
Atmospheric Administration (Chris Zervas).
In addition to hosting the map tool, the national report, state fact sheets, and the peer-reviewed papers, the website, SurgingSeas.org, includes downloadable data for all the cities, counties
and states studied; embeddable widgets; republishable graphics; and links to dozens of local, state and national
planning documents for coping with rising seas.
The website also shows how the threat from climate change-driven
sea level rise and storm surge is expected to increase over time at
55 tidal gauges around the U.S. and near most major coastal cities.
At the majority of these gauges, floods high enough to formerly be
called worse than once-a-century events have more than doubled in
Land, housing and population vulnerability estimates are based
on 2010 Census data and on land elevations relative to potential
water levels, and do not take into account potential protections.
However, properties behind walls or levees may suffer enhanced
damage when defenses are overtopped, or during rainstorms, because
the same structures that normally keep waters out can keep
floodwaters in once they arrive.
"Escalating floods from sea level rise will affect millions of
people, and threaten countless billions of dollars of damage to
buildings and infrastructure," Strauss said. "To preserve our
coastal towns, cities and treasures, the nation needs to confront
greenhouse gas pollution today, while also preparing to address sea
level rise that can no longer be avoided."