As you know, the Clean Air Act was passed by the U.S. Congress and signed by the president. (It was originally enacted and then signed by President Richard Nixon in 1970, and amended in 1977 and 1990.) In 2007, the U.S. Supreme Court affirmed the authority, under the Clean Air Act, to regulate carbon dioxide as a pollutant. Therefore, curbs on carbon dioxide emissions are, in effect, mandated. The changes now under way may not proceed as smoothly as we would like, but increased use of alternative sources of energy and energy conservation are crucial to our economy, our health, and our survival.