A theme that we'll see several times throught this course is that of unintended consequences.
When we undertake a policy action for the purpose of something good, we often create ancillary effects that are bad. Luckily, the tools of economics often can help us predict these outcomes.
Subsidizing ethanol from corn raises food corn prices and actually creates more pollution. oops.
CAFE standards mandating high MPG for automobiles decreases the marginal cost of driving so people drive more, creating more pollution. oops.
and from today's USA Today: Protecting one species harms another species. oops.