Welcome to the Cato Daily Podcast for Thursday, April 5th. I'm your host Anastasia Glova.

Many questions are left unanswered after the Supreme Court ruled in Massachusetts V EPA that carbon dioxide

emissions are a pollutant that falls within the

regulatory purview of the Environmental Protection Agency. Among the questions

will the EPA comply or will it provide scientific evidence against regulatory action?

Are the courts now fair game for further environmental litigation and how does this case

alter standing doctrine for future cases.

To sort all this out, today's guest is Cato Senior Fellow in Constitutional Studies, Mark

Mahler.

What was the court's holding in Massachusetts V EPA?

Well, this was a case that started with a petition filed by a number of states and nonprofit groups.

And they asked the EPA to regulate what are called greenhouse gas emissions, emissions by cars like

CO2 that are said to contribute to global warming. And the EPA declined to take up this invitation to regulate these emissions.

The groups then filed suit in court and they essentially said that the Clean Air Act not only covers these greenhouse gas emissions,

but it obligates the EPA to step in and regulate, and that the EPA has essentially abdicated its statutory duty to deal with the global warming problem.

The groups lost in the lower courts and then it went up to the Supreme Court.

The Supreme Court agreed to an extent

with these environmental groups.

It said that the Clean Air Act does cover

global warming emissions, and it said that the EPA needs to reconsider the petition.

One thing it didn't say is that the EPA has to step in and regulate right away.

It simply said that the EPA hadn't come up with good enough

...