I don't need to know about electric vehicles

Rich Barnett writes to the editor of the Spectator: 

Martin Vander Weyer might continue to bang the drum for electric cars and their ‘green’ credentials but the problem is that in the drive for such cars we have effectively seen a cessation in development of petrol and diesel engines....[Y]our correspondent swerves the issue of just how clean these [electric] cars are, especially when we follow the production process back to the raw materials. In reality, the cleanest cars are those already built and maintained. Rich Barnett, the Spectator, 9 July

Mr Rich may be right or wrong. I don't know. But, as an advocate of policy that targets meaningful environmental outcomes, I don't need to know. It might be true that the environmental costs of electric vehicles is higher than that of petrol and diesel vehicles now; but that could change. What is the probability that legislation made today can correctly calculate even today's relative environmental costs, let alone those of any future time period?

My suggestion is that instead of trying to work out the best ways of improving the enviroment when our knowledge of ever-changing relationships between cause and effect is inescapably scanty, we target those environmental goals we want to achieve and reward people for achieving them. This makes better sense for two main reasons: 

• There is far more consensus about what those goals should be than the supposed means by which they can be achieved.  
• Technology, and our knowledge of the relationships between cause and effect are changing constantly in ways that nobody and, in particular, no regulatory body, can anticipate. 

When governments favour, whether by subsidy or other means, what they believe to be the most efficient way of achieving certain ends they are often looking only at current technology and short-term goals. Our environmental problems, though, require a long-term approach. Environmental Policy Bonds aim not only to re-focus policy on long-term goals but to inject the market's incentives into their achievement.