MILLBROOK, N.Y. - What would you do if you had a neighbor who fouled the air your children breathe, poisoned the fish your family eat and flooded the coastal communities where your family has vacationed each summer? How would you respond if your neighbor said he knew all these things were true -- even bad -- but he planned to continue these activities? You've got that neighbor, and it's Duke Energy.

With receipt of a permit from the N.C. Division of Air Quality, Duke Energy is now allowed to proceed with the construction of its proposed Cliffside coal-fired power plant west of Charlotte, an acknowledged emitter of 6 million tons per year of carbon dioxide as well as substantial quantities of nitric oxide, sulfur dioxide and mercury.

The permit requires Duke Energy to close some old power plants that also emit about the same quantities of these compounds. But a real advance in environmental quality will come only when the total emissions of these contaminants are actually reduced from today's levels -- not simply by substituting the emissions from old power plants with those from a new one.

The emissions of carbon dioxide are among the most egregious of those allowed to Duke Energy. This gas is the main source of global warming, now accepted as a human-induced alteration to our climate with numerous, costly consequences to coastal property, agriculture and human health. Coal-fired power plants are the major source of carbon dioxide from human activities in this country. Numerous alternative ways of saving energy and generating power are actively being pursued by electric utilities across the nation.

North Carolina's coal-fired power plants are largely fed by coal from mountain-top removal in the Appalachians. It doesn't take many clicks of Google Earth to see the mining scars to the landscape that leave the people of that region with deforested hillslopes, polluted water and fewer options to pursue a better life.

Coal delivered and burned in North Carolina emits nitric oxide -- an air pollutant directly attributed to ozone and childhood asthma. Sulfur dioxide from coal-fired power plants is also a significant source of atmospheric particulates, with substantial health impacts in patients with heart and respiratory problems. The proposed new plant will not reduce sulfur dioxide emissions below that of the older plants to be retired, and will thus not reduce current levels of acid rain and particulate air quality.

All coal contains small amounts of mercury that is emitted during combustion. Mercury deposited from the atmosphere in lakes downwind of coal-fired power plants is often transformed to its toxic form, methylmercury, which accumulates in fish, leading to mental retardation and birth defects in young children. Power companies will argue that the atmosphere naturally contains some mercury from volcanic eruptions and emissions from wetlands. They are right, but there is no reason to suspect that those emissions have increased during the past few decades. Industrial emissions, largely from coal, now dominate the atmospheric burden of mercury and these emissions are clearly responsible for the recent increases in mercury in fish.

North Carolina has led other states in its implementation of its Clean Smokestacks Act and in its recent establishment of a Renewable Energy Portfolio, requiring electric utilities to generate 12.5 percent of their power from renewable sources by 2021. This is not the time for North Carolinians to let Duke Energy stall these advances with the construction of the new Cliffside unit that will lock us into old technologies for five decades or more. It is time to clear the air by asking the Division of Air Quality how it could approve this power plant, and then to clear the air for future generations by revoking the new permit.

(William H. Schlesinger is president of the Cary Institute of Ecosystem Studies in Millbrook, N.Y., and emeritus professor in the Nicholas School of the Environment and Earth Sciences at Duke University.)