Scientists have developed ways to turn ordinary garbage into energy. “Biomass”—organic refuse such as corn stalks that can be turned into energy—is being used to produce ethanol, which is mixed with gasoline to help power automobiles.

Biomass fuel is a renewable energy source and therefore—unlike fossil fuels—is inexhaustible. An additional advantage of developing renewable energy sources, which also include solar and wind power, is that the United States could decrease its dependence on foreign oil suppliers. Another benefit of renewable energy sources is that many of these alternatives are less harmful to the environment than are fossil fuels. For example, solar panels transform energy from the sun into electricity without emitting any pollutants. Greenpeace, an organization devoted to exposing and solving global environmental problems, argues that “renewable energy will...