Under an agreement with U.S. regulators, American Electric Power Company of Columbus, Ohio, has agreed to offset part of its 145 million metric tons of carbon dioxide emissions by paying another company to lay plastic tarps. These tarps cover farm lagoons holding rotting livestock wastes that emit methane gas 21 times more damaging to the atmosphere than carbon dioxide. The annual methane produced by a typical 1,330-pound cow translates into about 5 metric tons of carbon dioxide emissions per year.
a. How many cows' worth of manure would have to be covered to offset the carbon dioxide emissions of this single electric utility?
b. Given that there are about 9 million cows in the United States in a typical year, what percentage of its carbon dioxide emissions could this firm offset if it paid for all cow manure in the entire nation to be covered with tarps?