VW scandal holds important climate lessons

A 2016 VW Golf TDI undergoes emissions testing at the California Air Resources Board lab in El Monte. CARB researchers helped uncover cheating by Volkswagen.
A 2016 VW Golf TDI undergoes emissions testing at the California Air Resources Board lab in El Monte. CARB researchers helped uncover cheating by Volkswagen. Bloomberg

In September, the U.S. Environmental Protection Agency and the California Air Resources Board announced that Volkswagen, the world’s largest automaker, had illegally modified its passenger diesel vehicles so they could pass clean air tests under laboratory conditions but emit as much as 40 times the legal limit of dangerous pollutants under normal driving conditions.

The announcement set off one of the most significant industrial scandals in recent history. In addition to devastating the VW brand and shaking up its leadership, government officials around the world have begun taking a much closer look at all types of cars.

Which other vehicle manufacturers might be cheating the system? How can we catch them? In an era of increasingly computerized vehicles and engines, how do we prevent cheating – or even legally gaming the system – in the first place?

The gist of the VW story may be familiar by now, but what many people don’t fully appreciate is the critical role of California’s regulators, and why it matters for the long run. Starting in 2011, CARB researchers and other global vehicle technology experts, including my staff at the International Council on Clean Transportation, became aware that nitrogen oxide emissions from passenger diesel vehicles in Europe were much higher than air quality standards allowed.

These vehicles were passing emissions tests, but then spewing many times the permitted nitrogen oxide under real-world driving conditions: stop-and-go traffic, up-and-down hills and sudden acceleration and deceleration. Many suspected that relatively lax compliance and enforcement in Europe were to blame.

In 2012, we approached CARB for support for a series of tests that, we hoped, would confirm that suspicion. During 2013 and 2014, we brought in West Virginia University to conduct real-world tests of three passenger diesels: a VW Jetta, a VW Passat and a BMW. Our hypothesis was that these vehicles would be clean under normal driving conditions because of the stricter compliance and enforcement program in California and the U.S. compared to Europe. We turned out to be part right. The BMW performed well, but the VWs had extremely high emissions.

What CARB did next, in close collaboration with the EPA, provided the critical evidence. It initiated an investigation that led to a voluntary recall of VW passenger diesels in California last December, then it retested the vehicles that VW had supposedly fixed. When the fix didn’t significantly change the pollution results, CARB and the EPA forced the automaker to admit it was cheating.

There are two important lessons we should learn from the VW fiasco. The first is that stringent emissions standards for cars are effective only if combined with strong testing, the authority to require vehicle recalls and penalties to deter future cheating. Importantly, CARB is seeking additional funds to upgrade its testing facilities to make it easier to detect “defeat devices” or other types of cheating by automakers. Leaders in Sacramento should support this proposal.

The second lesson has far broader implications. Next month, world leaders will gather in Paris for the United Nations Climate Summit. Global negotiators need to ensure that pledges to reduce emissions are backed by compliance and enforcement programs that work. This will require a concerted action on the part of many countries and regions, including Europe, China and India.

For 50 years, California has shown the world how to reduce air pollution with new technologies, while continuing to enjoy strong economic growth. Policymakers around the world are turning to CARB for advice on making clean vehicle policies effective. As more nations profit from their experience, we’ll all be able to breathe a little easier.

Drew Kodjak is executive director of the International Council on Clean Transportation, a nonprofit research group with offices in Washington, D.C., and San Francisco. He can be contacted at