Today we'll be hearing from an environmental economist.

Now that very title may strike you as a bit oxymoronic.

Economists are interested in what is the right level of pollution.

The main issue at hand today is legislation passed in California back in the 1970s

that required new houses to be much more energy efficient.

The California Energy Commission projected at the time that homes built after the standards were enacted

would use 80% less energy.

So did new homes in California really use 80% less energy?

You think I'd be asking this question if the answer were yes?

Along the way, we'll hear what an environmental economist can get away with saying

even when he's advising the President of the United States.

Well, I don't like that idea. If you think I'm speaking out of turn, fire me.

I have a better job back home.

And finally, we try to solve some of the environmental puzzles that you, our podcast listeners, like to send in.

My favorite quote from all of this came from Betty Friedan, who said she would rather

help the environment by not using disposable coffee mugs

and pouring the scalding hot coffee directly into her hands than use cloth diapers.

From WNYC, this is Freakinomics Radio, the podcast that explores the hidden side of everything.

Here's your host, Stephen Duffner.

We are having a conversation today with Eric Levinson.

I'm an economics professor at Georgetown University.

Okay. And Eric, when I look at the papers you've written about,

...