Determining an acceptable level of risk.

Avoiding havoc A recent study by the Environmental Defense Fund shows that power plants, industry, and automobiles are leading sources of the nitrogen pollution that wreaks havoc on coastal ecosystems. Explosive blooms of algae nourished by nitrogen suffocate fish and shellfish populations and invade swimming beaches. Scrubbers on smokestacks designed to trap sulfur do not control nitrogen, but energy efficiency reduces both. Energy efficiency can be a new weapon in the air pollution wars, complementing scrubbers and catalytic converters. Czechoslovakia, East Germany, Poland, and others could stem the damage to their forests by improving their industrial energy efficiency. Rome could anack the cause of much of the population’s respiratory disease and slow the deterioration of its ancient Nins by doubling the fuel efficiency of its cars. A 1987 study by the American Council for an Energy-Efficient Economy concluded that increased eft? ciency could help widen the scope and improve the cost effectiveness of proposed acid rain control programs. The ultimate environmental problem may be carbon dioxide accumulating in the Earth’s atmosphere-threatening to irrevocably alter the world’s climate. Already, the average temperature worldwide has increased by I “F in the last 100 years. This “greenhouse effect” could well make the world warmer 50 years from now than it has been at any time in human history. The main cause of this phenomenon is fossil fuel combustion, which adds 5.4 billion tons of carbon to the atmosphere each year-more than one ton for each person on the planet. The full implications of such a warming are not fully understood, but they could well include more frequent droughts, serious disruptions in agriculture, and the flooding of densely populated coastal areas. Governments throughout the world not only have been slow to respond to the climate problem and other environmental threats but also are actively pursuing energy policies that aggravate them. Sustained improvement in energy efficiency must be the central component of any viable strategy to limit global climate change. No other strategy can be developed quickly enough to slow global warming significantly in the next few critical decades. A demanding but achievable goal is an annual 2% gain in energy efficiency. The energy crisis of the seventies has receded for the time being, but the environmental limits on energy growth continue to press closer. Fuel prices are low, but the environmental costs of energy profligacy are mounting rapidly. Energy efficiency is an economic op portunity, but it is fast becoming an environmental necessity.