Commentary

NEW YORK IN THE GREENHOUSE

by Albert F. Appleton

As 2000 begins, the debate over the greenhouse effect has ended. After a decade when almost every succeeding year set new heat records, both the scientific community and the public have recognized that the greenhouse effect is not only a future, but a current reality.

But beyond a recognition that summers are uncomfortably warmer, and that snow may become a memory, New Yorkers have only a vague understanding of what the greenhouse effect will mean for them.

Over the next 25 years, the average local temperature could rise as much as two degrees annually. That means winters as warm as the Carolinas and summers with 30 day stretches of consecutive ninety degree days. Heat related deaths will climb, and summer activity will migrate indoors. Deer, geese, mosquitoes, ticks and other pests which cold winters have helped control will flourish. Air pollution and related respiratory illness will increase.

But the worst and most costly greenhouse effect impacts will be on water supply, suburban flooding and coastal areas.

The New York City water system is the centerpiece of the Region's water supply. Rainfall in the City's watersheds currently averages an ample 45 inches a year. But the greenhouse effect is expected to significantly alter precipitation patterns between north latitudes 40 and 50. The prediction for New York is the worst of both worlds, significantly increased frequency of drought alternating with recurrent and severe storm events.

In the driest year in New York history, 1964, watershed rainfall totaled 27 inches, 40% below normal. That level of drought is likely to become much more common as the greenhouse effect kicks in. If that happens, New York's current water supply comfort would vanish, and the City would have to turn to the Hudson River as a primary water source. Meanwhile, as sea levels rise because of the greenhouse effect, the salt front in the Hudson River will move north, well above Poughkeepsie. The cost of going that far north to get reliably fresh water, with the filtration that Hudson river water will require, will be well above $10 billion.

Regionally, the water supply threat is even worse. None of the region's other surface water systems have New York's 14 month storage capacity. The greenhouse effect will hit them even harder. Long Island, totally groundwater dependent, faces the intrusion of salt water into its aquifers. Throughout the Region, the greenhouse effect could mean desalinization or a scramble to build new water systems to tap the few sources, like the Hudson River, that will still have surplus water. To foresee the Region spending $50 billion on new water infrastructure because of the greenhouse effect is not unreasonable.

The expected counterpoint to more drought is more frequent, severe storms. This other side of the increased extremes of weather expected from the greenhouse effect will hit New York in another dramatic and costly way: increased suburban flooding.

Flooding in suburban counties such as Westchester and Bergen is already a regular occurrence during major storms. Since time out of mind, suburban developers have located developments on flood plains and filled wetlands, and highway departments have taken the course of least resistance and built their roads parallel to local streams. Meanwhile, as development replaces forests and vegetated areas that absorb rainfall, runoff is becoming faster and more concentrated. The greenhouse effect will make costly, disruptive flooding a regular feature of much suburban life and, over time, another multi-billion dollar big ticket item.

Most experts expect one to three feet of sea level rise from the greenhouse effect over the next century. In the great Nor'easter of 1992, major portions of Staten Island, Coney Island and low lying areas in Queens and Bronx were flooded, numerous highways were closed, and beach damage was immense. As sea levels rise, such storm impacts will become routine. Ultimately, the Region will have to dike, or retreat from, its many low lying coastal areas. And in a City where enormous portions of its waterfront land are filled land, numerous subways, basements, computer and communications facilities are already below sea level and will be similarly vulnerable to periodic flooding.

$50 billion in costs from these coastal and suburban flooding problems again seems plausible. Thus the greenhouse effect represents a potential $100 billion liability for the Region in the next quarter century.

Of course, these cost numbers are far from certain. But perversely, that only makes the public policy problem worse. Designing and building new water systems, diking low lying areas, moving roads, reworking the interactions of suburban land use and hydrology are one to two decade efforts at a minimum. The Region then faces the following dilemma. The greenhouse effect is real and accelerating, but we will not know its exact impacts until most of the time to take effective remedial action has passed. Thus, over the next fifteen years the Region will face a brutal choice: act quickly and risk unnecessarily spending billions if the greenhouse effects are less than anticipated; or wait and risk losing tens of billions in avoidable damage costs.

Starting around 2005, the cost for New York of the greenhouse effect could steadily mount--to over $5 billion a year over the next 20 years. The implications of this fact in terms of addressing other long overdue infrastructure deficits, from school buildings to new mass transit, is grimly obvious.

Five years ago, the greenhouse effect was the esoteric concern of a small, knowledgeable coterie. Today, it is a generally accepted public reality, but only at the level of discontent with a warmer and less snowy climate. Five years from now, it will be widely recognized as a major peril to the Region's quality of life and financial future, with a potential $100 billion price tag, and posing some of the most difficult choices in the Region's history.

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Albert F. Appleton, a Senior Fellow at the Regional Plan Association, is a former Commissioner of the New York City Department of Environmental Protection, which runs the New York City Water and Sewer System.

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