Kolbert: What role should corporations play? Corporations are arguably the most powerful force in the United States today.

Gelobter: It's not going to be gentle. ExxonMobil is the world's most profitable company -- its market valuation is equivalent to the market valuation of the entire world auto industry. Their shareholders should fire them if they try to change their business. It's our job to force them to change their business through legal avenues and personal choices.

Schmidt: But many businesses have a vested interest in sustainable business practices. They employ time scales and planning that go way beyond election cycles. While some corporations think short-term, many have foresight. A lot of people in the business community are part of the solution, not part of the problem, and that needs to be tapped into.

Kolbert: What about technological solutions?

Gelobter: I'm against building more nuclear plants. I'm against carbon sequestration because I don't think it'll be safe to bury millions of tons of carbon deep underground. And I'm against relying on oil. We have to shut refineries down.

Kolbert: But then you've got to tell everyone that they can't drive their cars either.

Gelobter: No, over time you can go to better mass transit, greater density of housing, biofuels, more efficient use of resources.

Schmidt: Well, here we have a very concrete example of disagreement. Without carbon sequestration I believe we might as well just go home on the climate change issue. If we don't allow for the possibility of carbon sequestration, people will not invest in more efficient IGCC [integrated gasification combined cycle] power plants that have the potential for carbon sequestration. That means they will not have the option in 10 or 20 years' time, when it become much more obvious that CO2 emissions need to be cut, to retrofit those plants to sequester carbon.

Kolbert: Michel's not letting them build these plants, though.

Gelobter: We can't give them 20 years -- we've got to drive a stake through their heart today.

Orr: No one knows whether carbon sequestration can work -- the recent MIT study had enough caveats in it to choke a horse. That study says it will take at least 10 years to figure out whether you can put carbon underground and hold it there in perpetuity. And it would have to be done at a cost that competes with energy efficiency improvements and renewable energy sources like wind and solar. Last spring the American Solar Energy Society said that you can get most of where you need to go, 90 to 100 percent, through efficiency and renewables. But if you look at the number of dollars spent on research and development, efficiency and renewables are down at the bottom, way behind nuclear power and "clean coal."

Schmidt: I'm not asking for a special exemption for carbon sequestration -- it has to compete on both efficiency and price. But to rule it out for China, which has so much cheap coal, where they're focused on keeping their people happy, and they need energy? To say, "Starting today, no more coal power plants" is politically unrealistic. Allowing for the possibility of carbon sequestration lets us bring those people on board and have a chance to get to the point where we have zero emissions.

Gelobter: If we give coal a lifeline, we never get wind and solar. If you keep that dynamic in the marketplace, that coal is still cheaper, especially if the right president is in place, you never get the incentive to invest in the good stuff.

Schmidt: But if it could compete on price --

Gelobter: No, I don't want it to compete on price because I want to kill 'em. Because they're killing us.

Kolbert: Yes, but you haven't addressed Gavin's point that even if you could do that in Washington, you can't do it in Beijing --

Orr: All the studies I've seen for 25 years show that saving energy is a lot cheaper than making it. This was Amory Lovins's point back in 1976. We have a whole shelf of studies that say you shouldn't try to increase supply; decrease demand instead. Demand-side management worked in California --

Schmidt: That's a very good lesson because per capita energy use in California has stayed static over the past 30 years while it's been increasing everywhere else in the country.