The Index of Leading Environmental Indicators: Key Findings

Published May 1, 1998

Air Quality

Perception: Air quality is worsening as pollution levels rise and pose a serious threat to human health.

Reality: Since 1980, there has been an overall improvement in air quality by more than 40 percent. Ambient levels of all air pollutants targeted by regulations have declined since the 1970s. (Ambient levels are the actual concentrations of a substance in the air, as opposed to emissions, which are estimates of the amount of substances generated by human activity.)

  • The air in most metropolitan areas is improving. Nitrogen Oxides (NOx) and Volatile Organic Compounds (VOCs) combine in sunlight to form ozone, the major component of urban smog. Between 1975 and 1995, ambient levels of NOx in the U.S. declined by 37.3 percent, and ambient levels of ozone decreased by 25.7 percent between 1976 and 1995.
  • Acid rain is not a threat. It has no observable effect on human health, nor has it damaged North American crops. Sulfur dioxide is the principal component of acid rain. Ambient levels of SO2 decreased 60.7 percent between 1975 and 1995; emissions have decreased 41.2 percent since 1970.
  • Levels of carbon monoxide and particulate matter (PM) are falling. Ambient levels of carbon monoxide (CO), caused mostly by car emissions, fell 67.3 percent between 1975 and 1995. Ambient levels of PM, more commonly known as dust and soot, have decreased 22 percent since 1988.

Water Quality

Perception: Pollution is causing water quality to deteriorate, threatening human health.

Reality: Water quality, though difficult to measure, is improving.

  • Industrial pollution is dropping. “Point source” or industrial pollution has decreased over the past decade. Organic wastes have fallen by 46 percent, toxic organics by 99 percent, and toxic metals by 98 percent.
  • Rivers and streams are cleaner. Measures of phosphates, fecal coliform, and dissolved oxygen exceeding local standards in rivers and streams decreased between 1974 and 1994.
  • The Great Lakes are getting cleaner. In the Great Lakes, pesticides and contaminants such as DDE, DDT, PCBs, and HCBs have fallen considerably since the 1970s.

Natural Resource Use

Perception: Natural resources are being consumed faster than they can be replenished; a resource shortage and energy crisis loom.

Reality: Those widespread concerns are simply unfounded.

  • Forest are not disappearing. Each year the U.S. plants more trees than it harvests. In 1995, the U.S. Department of Agriculture spent $9.3 million planting 141,194 acres of trees and preparing 1,845 acres for natural generation.
  • Fresh water supplies are not being depleted. The U.S. consumes less than 20 percent of its available renewable fresh water resources. Between 1980 and 1990, total water use in the U.S. decreased by 9.5 percent.
  • The U.S. is becoming more energy efficient. U.S. per-capita consumption of energy was lower in 1995 than it was in 1979. Both the U.S. and Canada produce more energy than they consume, with the U.S. consuming only 85 percent of what it produces.

Land Use

Perception: The “sprawl” of urban areas threatens to destroy agricultural lands and wilderness areas.

Reality: Neither wilderness areas nor farm lands are in danger.

  • Wetlands are not disappearing. Since 1980, the United States has suffered no net loss in wetlands. Canada, which has 25 percent of the world’s wetlands, has suffered no net loss in wetlands since 1986.
  • Urban sprawl is exaggerated; cities and towns are not overrunning agriculture and wilderness lands. In the U.S., urban areas comprise only 4.6 percent of total land base. The comparable figure for Canada is 1 percent.
  • Agriculture is becoming increasingly productive. The American agriculture sector was 158 percent more productive at the end of the 1980s than at the beginning of the 1960s. Canada’s agricultural production grew by 206 percent during the same period.
  • Protected wilderness areas are increasing. In the U.S., the ratio of protected areas to urban and agricultural lands grew from 6.4 percent to 22.9 percent between 1959 and 1997.

Solid Waste

Perception: The U.S. produces more garbage than it can accommodate and is not recycling enough.

Reality: Research shows these widespread concerns, too, are unfounded.

  • North America is not producing more waste than it can accommodate. Although many current landfills are close to capacity, this is because they are small, designed to have a short life-span, and thus often are at near-capacity. This does not mean that the U.S. is “running out of room” for landfills. A single square of land, 171 miles on each side and about 115 feet deep, could accommodate all the garbage generated in the U.S. for the next 1,000 years.
  • Recycling levels continue to increase. Between 1980 and 1994, paper and cardboard recycling in the United States increased from 22 percent of consumption to 35 percent. Glass recycling rose from 5 percent to 23 percent over the same period.