Tunnels leading to Manhattan would be flooded in less than 60 minutes in an Irene-like storm if sea levels rise as expected because of climate change, according to a new report.
Many of the cities streets would also be flooded and the cost of damages would run to $58 billion at the current sea level, the report said.
"The risks and the impacts are huge," Art deGaetano, a Cornell University climate scientist and lead author of the report, . "Clearly areas of the city that are currently inhabited will be uninhabitable with the rising of the sea."
The 600-page report called ClimAID, intended as a resource for planners, policymakers, farmers and residents, says New Yorkers should begin preparing for hotter summers, snowier winters, severe floods and a range of other effects on the environment, communities and human health.
It was written by scientists from Columbia University and the City University of New York, as well as Cornell, and funded by the New York State Energy Research and Development Authority.
In a section entitled "Sea Level Rise and a 100-year Coastal Storm," the report said that by the end of the century it was projected that the sea would rise by 2 to 4 feet.
"Damages from a coastal storm in the New York City metropolitan area that currently occurs on average once every 100 years would be significant. At current sea level, economic losses from such a storm would amount to about $58 billion. Losses under a 2-foot sea level rise scenario increase to $70 billion and to $84 billion under a 4-foot sea level rise scenario," the report said.
"...The effects of such a flooding scenario would occur rapidly. For example, many of the tunnels lying below flood heights (including subway, highway, and rail) would fill up with water in less than 1 hour," it added. "At the low-lying La Guardia Airport, sea level rise would wipe out the effectiveness of existing levees, even for less severe storms."
DeGaetano said this year's weather had provided "a good teachable moment" about what could be expected in future.
"What we show in the report is that winters will tend to get wetter and summers drier. Conditions this year were textbook for that," he added. "Farmers had a tough time getting into wet fields this spring, then there were droughts. The flooding from Irene and Lee brought the classic types of impacts we project to occur in the report."
The study predicts average annual temperatures in New York state will rise by 4 to 9 degrees by 2080 and precipitation will rise by 5 to 15 percent, with most of it in the winter.
It predicts that along the seacoast and tidal portion of the Hudson River, the sea level will rise by 1 to 5 inches by the 2020s and 8 to 23 inches by the 2080s. If melting of polar ice caps is factored in, sea level is projected to rise 37 to 55 inches by the 2080s, the report says.
Among the specific regional effects predicted in the report are:
- Native brook trout and Atlantic salmon will decline, but bass will flourish in warmer waters.
- Great Lakes water levels will fall.
- Apple varieties such as McIntosh and Empire will fare poorly, but vineyards will benefit.
- Milk production will decrease.
- Coastal wetlands will be inundated and saltwater will extend farther up the Hudson River.
- Adirondack and Catskill spruce-fir forests will disappear.
- Invasive insects, weeds and other pests will increase.
- Electrical demand will increase in warm months.
Minorities hardest hit
The study proposes numerous steps that can be taken to adapt to the changing climate.
Improving insulation and using reflective roofing materials could keep buildings cooler in summer, reducing electrical demand from air conditioning. Avoiding development in coastal zones and river flood plains could reduce the damage from flooding.
The report says certain demographic groups will be disproportionately affected by climate change. Minorities and low-income residents tend to live in areas vulnerable to flooding in New York City and upstate, DeGaetano said.
Rural residents and small towns are less able to cope with extreme events such as floods, ice storms and droughts.
Elderly people and those with health problems are more vulnerable to heat-related illnesses such as asthma, the report says. Farm workers may be exposed to more chemicals if pesticide use increases in response to climate change.
The report lists a number of climate changes in New York that have already been observed:
- Annual average temperatures have risen about 2.4 degrees since 1970, with winter warming exceeding 4.4 degrees.
- The sea level along New York's coastline has risen about a foot since 1900.
- There's been no discernible trend in annual average precipitation for the state as a whole since 1900, but intense precipitation such as heavy downpours have increased in recent decades.
"Climate change is already beginning to affect the people and resources of New York state, and these impacts are projected to grow," the ClimAID authors wrote. "At the same time, the state has the potential capacity to address many climate-related risks, thereby reducing negative impacts and taking advantage of possible opportunities."