FACTORS OF LONG-TERM ENVIRONMENTAL IMPROVEMENT
Contrary to popular belief, environmental quality in the United States has been improving and continues to improve. Water quality is better than it has been in the last 100 years. The six pollutants that adversely affect outdoor air quality are down significantly. Indoor air quality is much better. On net, we have more wetlands. The number of forested acres has increased. Regulation has undoubtedly encouraged many of these improvements. But, environmental quality was improving for decades prior to the regulations being enacted.
Water quality today is far better than it was a century ago.
Figure 1 shows the number of cases of four of the most common waterborne diseases from 1900 to 1970. In 1900, 35 Americans per 100,000 died of typhoid and paratyphoid, 8 per 100,000 died of malaria, and 12 per 100,000 died of dysentery.
By 1970, four years before the passage of the Safe Drinking Water Act, all those death rates had fallen virtually to zero.
Major improvements have been made in technologies that promote fewer emissions and cleaner air, resulting in better overall air quality.
Figure 2 tracks the amount of emissions from seven common pollutants, while adjusting for real GDP from 1940 to 1997.
Air pollution has been declining for more than a century. Improvements in air quality over time were due to newer, more efficient technologies entering the marketplace, state and local regulations, and increasingly effective nuisance suits against polluters. Air pollution in America was declining long before the Clean Air act nationalized pollution control in 1970.
Land is one of the most visible and tangible representations of environmental quality, and there are encouraging trends that suggest land conditions in the United States are getting much better.
Figure 3 shows the amount of forested area in the U.S. relative to population dating back to 1850. While U.S. population has grown by more than 250 million persons, the amount of forested acres has stayed relatively the same, and is even trending upward.
Not only are the number of forested acres increasing, so are the number of wetland acres. Also, agriculture, the most land-intensive human activity, is becoming increasingly efficient in the United States. Production of several major crops, including corn, rice, soybeans, and others has increased more than 14 fold since 1940, while acreage of harvested land has increased by only 4 times.