Fuel economy non-change will have no impact on global warming. The Trump administration has canceled a scheduled increase in Corporate Average Fuel Economy Standards. Automakers will be marginally freer to make and sell vehicles they think consumers actually want. Environmentalists are criticizing the move, but how much will it really add to global warming? The answer, Marlo Lewis writes, is zero degrees give or take a few thousandths of a degree 82 years from now:
Specifically, under the agencies’ revised standards, atmospheric carbon dioxide concentration would reach 789.76 parts per million in the year 2100 instead of 789.11 ppm—an 8/100th of a percent increase.
Assuming conventional (“consensus”) climate modeling, the extra 0.65 part per million of carbon dioxide would increase global average annual temperature by 0.003°C in 2100. Three one-thousands of a degree Celsius is 27 times smaller than the margin of error (0.08°C) for measuring changes in global average temperature. So, the climate impact of the Trump proposal would literally be undetectable under current scientific methods.
More importantly from a policy standpoint, an unverifiable bump of 0.003°C in global average temperature 82 years from now would make no practical difference to weather patterns, sea levels, polar bear populations, or any other environmental condition people actually care about.
[Marlo Lewis, Jr., “Trump Revision of Obama-era Fuel Economy Rules Is No Climate Disaster,” Competitive Enterprise Institute, August 10]