Contact: Bob Nelson For immediate release
(212) 854-6580 March 27, 1998
Warming Could Flood New York Metro Area
In Next Century, Columbia Scientist Reports
Global warming will make the New York metropolitan region not only
warmer, but wetter as well, according to a new Columbia University study.
Subways, airports and low-lying coastal areas could experience flooding if
global warming produces more violent storms and higher sea levels, as expected,
said Vivien Gornitz, associate research scientist at Columbia's Center for
Climate Systems Research. Local temperatures could rise by as much as four
degrees Fahrenheit, and sea levels could increase by up to eight inches by 2030
and by as much as four feet by 2100, under the most extreme scenarios, she said.
Dr. Gornitz presented the new work at the Metro East Workshop, held
March 23-24 at Columbia, one in a series sponsored by the federal government to
assess regional vulnerability to climate change. The results, with reports from 18
other regions, will be presented to Congress and the president by 2000.
Dr. Gornitz, who is also affiliated with the National Aeronautics and Space
Administration's Goddard Institute for Space Studies, was joined by co-authors
Cynthia Rosenzweig, adjunct research scientist at the Center for Climate Systems
Research; Chris Small, associate research scientist at Columbia's Lamont-
Doherty Earth Observatory; Richard Goldberg, research staff assistant at the
center, and David Rind, adjunct senior research scientist at Lamont.
Dr. Gornitz presented three scenarios for the period 1995 to 2030: a low-
change scenario that is her extrapolation of current trends without any
greenhouse-induced warming; a middle ground, based on simulations from the
Geophysical Fluid Dynamics Laboratory at Princeton University, and a high-
change scenario developed at the Goddard Institute, called Business as
Usual,that assumes greenhouse warming takes place without any mitigating
efforts. Temperatures in the metropolitan area increase over the period by one to
four degrees Fahrenheit, according to the models. None of the scenarios finds
significant increases in precipitation.
But all the scenarios show local sea-level rises, ranging from four to eight
inches by 2030, and maximum coastal flood heights of nearly six feet, an increase
of nearly a foot from current levels. That means that any area below six feet above
sea level would be vulnerable to flooding, including most of the lower Manhattan
shoreline, coastal and island areas of Jamaica Bay, much of downtown Hoboken
and Jersey City and south shore beaches in Staten Island and the Rockaways.
About an inch of the sea-level rise is really a ground-level fall, Dr. Gornitz
said. The northeastern United States is dropping by about one millimeter a year,
offsetting a rise in southern Canada, which was previously compressed by
glaciers. Local geological factors elsewhere may mitigate rising sea levels.
Scientists and policymakers may quibble over details, but when all models
show significant sea-level rises, it's time to pay attention, Dr. Gornitz said.
"Obviously, the best mitigating action would be to reduce greenhouse gases, but
that is proving to be extremely difficult, because many countries must agree to
limit their emissions," she said.
State and local planners should be thinking about countermeasures now,
Dr. Gornitz said. Areas that are just above sea level, including parts of lower
Manhattan and New Jersey, could be protected with seawalls. Runways at
Kennedy, LaGuardia and Newark airports could be raised above expected flood
levels. Pumping systems may be needed to keep the New York City subways dry,
and some coastal roadways, such as the West Side Highway, may need to be
moved inland, she added. The Columbia scientist called for rezoning of coastal
areas for parks and recreational uses, not high-density residential development.
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