Cooling the global-warming debate.

• Author: Anderson, Terry L.

In the March 2004 issue of Scientific American, National Aeronautics and Space Administration global-warming expert James Hansen notes that greenhouse gas emissions and global-warming projections are "consistently pessimistic." Hansen suggests that projections do not take into account the lower carbon dioxide and methane emissions that have resulted from technological advancements. He explains that the lower carbon dioxide emissions result from increased energy efficiency following the energy crisis in the 1970s and the lower methane emissions, from technological changes in agriculture.

Hansen's concludes on an optimistic note, saying "the main elements [new technologies] required to halt climate change have come into being with remarkable rapidity." This statement would not have surprised economist Julian Simon. He saw the "ultimate resource" to be the human mind and believed it to be best motivated by market forces.

Because of a combination of market forces and technological innovations, we are not running out of natural resources. As a resource becomes more scarce, prices increase, thus encouraging development of cheaper alternatives and technological innovations. Just as fossil fuel replaced scarce whale oil, its use will be reduced by new technology and alternative fuel sources.

Market forces also cause economic growth, which in turn leads to environmental improvements. Put simply, poor people are willing to sacrifice clean water and air, healthy forests, and wildlife habitat for economic growth. But as their incomes rise above subsistence, "economic growth helps to undo the damage done in earlier years," says economist Bruce Yandle. "If economic growth is good for the environment, policies that stimulate growth ought to be good for the environment."

The link between greenhouse gas emissions and economic prosperity is no different. Using data from the United States, Professor Robert McCormick finds that "higher GDP reduces total net [greenhouse...