NCPA - National Center for Policy Analysis

Cleaner Cars Contribute To Global Warming

May 29, 1998

A recent study from the Environmental Protection Agency says catalytic converters -- which have sharply reduced smog -- are a substantial factor in global warming. The federal government several decades ago ordered auto manufacturers to install the devices on cars.

Researchers have suspected for years that the converters sometimes rearrange nitrogen-oxygen compounds to form nitrous oxide, also known as laughing gas. Nitrous oxide is a greenhouse gas more than 300 times more potent than carbon dioxide -- the most common of the gases blamed for global warming by some environmental theorists.

According to the EPA:

  • Nitrous oxide now accounts for about 7.2 percent of the gases which supposedly cause global warming.
  • Cars and trucks -- most fitted with catalytic converters -- produce nearly half of that nitrous oxide.
  • Improvements in the converters which eliminated more of the nitrogen-oxygen compounds have only made matters worse by producing more nitrous oxide.
  • Nitrous oxide may represent about one-sixth of the global warming effect that comes from gasoline use.

Auto industry experts say they can solve the problem by adjusting the converters. But some environmental activists are already seizing on the problem to demand radical changes -- such as mandating development and use of electric cars.

"You've got people trying to solve one problem, and as is not uncommon, they've created another," observed one EPA official involved in the study.

Source: Matthew L. Wald, "Autos' Converters Increase Warming as They Cut Smog," New York Times, May 29, 1998.


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