Why more electric cars won't save the world from climate change

Last year, sales of plug-in electric vehicles in the United States were nearly double the sales total in 2012. But that's where the good news ends.

Despite the relatively positive sales numbers, sales of plug-in electric vehicles remain a tiny percentage of the overall auto market. While the total U.S. auto sales numbers topped 15 million, less than 100,000 electric vehicles were sold last year. The other disappointing news for electric cars: even if those sales numbers grow at such a rate that EV drivers represent a significant share of U.S. drivers , it wouldn't do much to impact one of the problems it aims to solve, air pollution.

That's according to new research from Joseph DeCarolis of North Carolina State University. In a paper, published this month in Environmental Science & Technology, DeCarolis said that his team ran more than 100 scenarios through an energy systems model to gauge the impact of electric drive passenger vehicles on air pollution in the United States. The findings: there's not much of an impact.

One particularly poignant example: Even if 42 percent of passenger vehicles in the United States were electric, there would be "little or no reduction in the emission of key air pollutants," like carbon dioxide, sulfur dioxide, and nitrogen oxide.

As DeCarolis explains in a press release:

There are a number of reasons for this. In part, it's because some of the benefits of EDVs are wiped out by higher emissions from power plants. Another factor is that passenger vehicles make up a relatively small share of total emissions, limiting the potential impact of EDVs in the first place. For example, passenger vehicles make up only 20 percent of carbon dioxide emissions.

That doesn't mean that electric vehicles don't have an important role to play in reducing pollution. Electric cars could, for example, be one of the many ways China will attempt to fight extreme smog in its cities. As we've also seen from China, even if pollution is highly concentrated in one place it can still have impacts thousands of miles away . Air pollution isn't bound to the places it's expelled. So if electric cars are used as a local solution to fight smog it will just push the problem to another place if the electricity grid isn't clean.

But electric cars aren't a silver bullet for broader climate problems either.

A better solution, according to DeCarolis, is to "set emissions reductions goals, rather than promoting specific vehicle technologies with the idea that they’ll solve the problem on their own," like the emissions targets the European Union has been hashing out this week.

Of course, the ultimate goal of emissions reductions in cars and entire countries is to mitigate the catastrophic impacts of climate change. And as the United Nations showed in a recent report, worldwide emissions will need to fall 40 to 70 percent between 2010 and 2050 for that to happen.

Clean cars could play a small role in those emissions reductions, but it seems like it would need come from auto innovations like this solar car to make much of a difference.

Photo: Flickr/Eneas

This post was originally published on Smartplanet.com