What You Can Do About Climate Change
and ANN ARBOR, Mich. What can you just one concerned person do about global warming? It may feel like a more urgent problem these days, with proposed cuts to the Environmental Protection Agency and each year warmer than the previous one. You could drive a few miles fewer a year. Reduce your speed. Turn down your thermostat in winter. Replace your incandescent light bulbs with LEDs. Reduce your meat consumption. Any one of those actions would help. But none would come close to doing as much as driving a fuel-efficient vehicle. If vehicles averaged 31 miles per gallon, , the United States could reduce its carbon dioxide emissions by 5 percent. Improving fuel economy carries particular salience after the Trump administration announced this month that it the progressively more stringent Obama-era fuel economy standards for vehicles in model years 2022 to 2025. This would be a big mistake as we try to slow down the warming of our planet and meet our international commitments on climate change. The simple fact is that American drivers are a significant contributor to greenhouse gas pollution, so having a vehicle fleet that burns less fuel can have an outsize impact on total emissions. Though the United States has just 4 percent of the worlds population, it is responsible for 14 percent of man-made greenhouse gases that end up in the atmosphere. Transportation accounts for 27 percent of those emissions. And 60 percent result from driving personal vehicles. Over two years, the average American driver travels a distance equal to the circumference of the earth. The average new vehicle gets only about 25 miles per gallon, which corresponds to about three-quarters of a pound of greenhouse gas emissions for each mile driven. Each year in the United States, 214 million drivers (with 240 million registered vehicles) drive 2.7 trillion miles, emitting about 2.4 trillion pounds of carbon dioxide into the atmosphere, based on the current fleet average of 21.4 m.p.g. Changing how much we drive is not easy; it often requires a major change in lifestyle, like moving closer to work or making more frequent use of public transportation, which often takes longer and is less convenient than driving. It is much easier to buy a more fuel-efficient vehicle; cars with fuel economy much better than the new-vehicle average of 25 m.p.g. are widely available. As our monthly monitoring of vehicle fuel economy shows, the average for new vehicles has increased to about 25 m.p.g. for model year 2014 from about 21 m.p.g. for model year 2008. Notably, however, of model years 2015 and 2016 vehicles did not improve. The main reason was the drop in the price of gasoline to $2.14 in 2016 from $3.36 a gallon in 2014. Now, fueling a less fuel-efficient but more spacious vehicle like an S.U.V. or pickup truck costs no more than fueling a small sedan did a few years ago. And buyers have responded by buying more of those bigger, less fuel-efficient vehicles. This is where the role of government and its fuel-economy standards for new vehicles becomes important. These standards have obvious direct effects on the industry in terms of what vehicles are made and sold, and their actual on-road fuel-economy performance. Significant increases in fuel-economy standards for all vehicles, but especially for pickups and S.U.V.s, are even more important when relatively low gas prices motivate buyers to choose larger vehicles over smaller ones. One of the last important acts of the Obama administration was to reaffirm the more stringent fuel-economy standards for model year 2022-25 vehicles, benchmarks that were originally proposed in 2012. Those standards would have ensured that the improvements in fuel economy that have stalled in recent years would resume. But the recently announced review of those standards by the Trump administration is bad news for the prospects of reducing both transportation emissions and the countrys reliance on fossil fuels. And that will make it that much harder to reduce the greenhouse gas emissions that are warming the planet to dangerous levels. is a research professor and is a project manager at the .