Mark Jacobsen Ph.D.

Professor of Economics

You are currently working with vehicle fleets to minimize the amount of smog emitted into the atmosphere. Can you briefly describe the vehicle fleets you work with and what "bad smog cars" are and their environmental impact?

I study the private vehicle fleet, meaning the personal cars and light duty trucks—including pickups and SUVs—owned by households. I mainly study choices and environmental consequences in the U.S. fleet which is currently about 200 million vehicles. My latest project involves considering smog-forming pollutants; much of my earlier work focused on greenhouse gas emissions and gasoline consumption. The incredible heterogeneity in pollution (some older vehicles and those with broken pollution control systems emit many times more pollutants than average) makes it a difficult problem for policymakers to address. States like California require individual vehicle testing (smog check), but this is quite expensive and still misses many problems. Most other states don't test individual vehicles at all, relying on pollution ratings from when the cars were new (EPA testing). The question I'm working on now is what sorts of policies we could use, other than or in addition to smog check, to help remove some of the worst vehicles. Policies like differentiated registration taxes (where the annual registration tax is based on what can be estimated about a vehicle's likely emissions) offer some potential gains and I am working on a statistical analysis to consider how big those gains might be.

As a UC San Diego Professor of Economics, has your passion and research always been environmentally focused?

Yes, for the most part. I enjoy the outdoors very much when I’m not at work and am happy to be able to study ways to preserve that environment for the future! I majored in economics as an undergraduate and relatively quickly decided that I wanted to study environmental policy. The tools of economics allow us to consider tradeoffs: How much do different policies cost, and, importantly, are there improvements that can be made so a policy with the same cost produces more environmental gain?

You’ve mentioned that, in your opinion, academia will play a fundamental role in filling the potential vacancy of environmental progress under the current presidential administration. Can you elaborate on this?

I would restate this as follows: I think that potential skepticism from the Trump administration about new environmental policies (though it is still unclear what changes the new leader of EPA will make) mean that it becomes even more important for academic economists to help identify the costs and benefits of policy. If we can more precisely understand the concrete gains that result from an environmental policy (things like reduced medical spending, increased worker productivity and improved property values) and the costs of policy (in cars this would be factors like reduced horsepower, or higher car prices holding horsepower the same) the best policy choice becomes clear regardless of political ideology. I also think that California is quite likely to push ahead with new environmental policies in spite of potential pressure from above to relax environmental policy. This creates a laboratory for studying the influence of policy changes (both from a physical science perspective and in studying the state's economy) that academics should find valuable for improving understanding.