Live Q&As

Excellent question. Yes, and no.

Yes, you clearly do build a movement by looking to people. Every marathon starts with the first step.

But that's exactly the point. We do need someone to organize that march on Washington to put the right policies in place.

What's all too often the case in the environmental movement is to give people top 10 lists of things they can do to solve global warming. Sadly, that's exactly the wrong way.

Recycling won't solve global warming. And if anything -- because of the well-documented phenomenon of the 'single-action bias' -- it may actually be a set backward.

I agree, honesty is key.

That means honesty about the science, and also -- like you say -- honesty about the policies. Promising "free lunches" probably isn't the way to go. We can't solve global warming by buying our way out of this problem, for example. We can't just go out and 'buy green.'

It turns out, many of the policies we are talking about are in fact rather cheap, and the benefits of action vastly outnumber the costs of it. Still, there are costs. They are small, but they are there. We need to be honest about that.

You are absolutely right. "Cap and trade" in many ways is a Republican invention. It was George H.W. Bush, who signed the first comprehensive cap-and-trade system into law, and it was extremely successful in cutting acid rain pollution.

Why the sudden opposition to doing something about global warming? I think for one important reason: those who oppose action or -- worse -- deny that the problem even exists *think* they don't like the solution.

That key word is "think." They think they don't like the solution because they believe this is the end of capitalism as we know it, when in fact it is quite the opposite. Markets aren't free enough right now. They are woefully rigged in favor of polluters.

So if anything, making polluters pay is about the most Conservative solution you can come up with: limit -- cap -- pollution, and get out of the way.

Sadly, I think you are on to something. Why worry about the planet if I have a family to feed?

Of course, that reaction is only natural. It turns out that you and I individually -- by doing our own little things like refuse that plastic bag at the checkout counter -- are indeed doing very very little that has real impact.

Yes, the seagull will notice if you don't toss that plastic bag in the river, but you haven't yet solved global warming.

So what does it take? We do need to look to large-scale policy changes to make a difference. If telling people to recycle more gets them to then vote for real change, great. I'm afraid it probably goes the other way: I've refused that plastic bag, well, I've saved global warming for the day.

Let me take the last bit first: The trends around global warming are about as clear as can be. The third-warmest decade ever? 1980s. The second warmest? 1990s. The warmest? The 2000s. The trend continues, and we've known for over a century now that it's carbon dioxide that's to blame. Sadly, that's no longer up for debate.

As for the argument around China or India? It turns out many others are, in fact, acting much faster than we are. India by now has a coal tax. China, as part of its 12th five-year-plan, is piloting seven cap-and-trade systems. Australia just passed a carbon price. New Zealand has comprehensive policy in place. Europe, of course, has been ahead of the curve for a long time now. Even here in the U.S. we have positive examples, most notably in California with its comprehensive cap-and-trade system for greenhouse gas pollution. It seems like only Washington is falling further and further behind.

That is indeed the major political hurdle, and again it comes down to some who think they don't like the solution. That plus the increased polarization in general, and you get to the impasse we are in right now.

What to do? I'd say focus on the kinds of solutions that are really working to make a difference and demonstrate how they are anything but a 'government takeover' of any kind. They are all about creating markets where there weren't any before. They are about leveling the playing field, about creating opportunities.

All of that has some surprising winners and losers. Exxon is often portrayed as the evil empire in the climate fight. It turns out there is some good reason to believe that Exxon may actually benefit from having carbon polluters pay their fair share. Their natural gas side of the business--perhaps around a third to half of their revenues--would likely benefit quite a bit from having a price on carbon that would make natural gas -- rather than coal -- the fossil fuel of choice for electricity generation.

Because both -- being vegetarian and not driving -- benefit me personally. I certainly don't do them because they'll stop global warming.

Although there's something to that second point as well: Me not eating meat or not driving isn't going to make a difference. But the point, of course, is that many many more need to live more sustainably and with a smaller footprint on this planet.

So in some ways, you can say that I'm living this way -- and teaching my one-year-old to live that way -- because I'm getting ready for a time when not getting that plastic bag at the checkout counter or biking or training it to work will be what everyone is doing.

The sad truth is that all of us are already paying a high price every day.

Every cross-country flight causes about a ton of CO2 emissions. That ton of pollution, in turn, causes at least about $20 worth of damages to health, ecosystems, and the economy. Who pays for that? We all do. Not the person flying, but all 300 million -- or rather all 7 billion -- of us. So you and I pay fractions of a penny everytime someone boards a plane.

Why not have that person, who also gets to enjoy the benefits of the trip, pay for the full damage of his or her actions?

That number isn't even that high. $20 for a roundtrip from Washington to Los Angeles. It's certainly less than you pay for that checked bag. Seems like a small price to pay to avert the worst consequences of global warming.

Global problem, global solution. So yes, ideally, we would have a global limit on greenhouse gas pollution, and the only way to do that is through a global treaty, as you point out. There may indeed be some significant movement in that direction. As slow as progress is at these UN negotiations, the latest talks in Durban, South Africa, pointed to some progress: We've at least agreed to negotiate just such a treaty by 2015, to come into effect by 2020.

But of course a treaty like that isn't enough. We depend on action and progress on the ground, by individual countries. There, I'd point once again to China, India among many others: South Korea is in the process of passing comprehensive legislation, Mexico just passed into a law an important framework, Brazil has an ambitious national emissions reduction goal.

But yes, the world is indeed (still) looking to the U.S. for leadership and to pass its own comprehensive climate and energy policy that will enable this transition toward a lower-carbon world.