Bjørn Lomborg feels a chill

Should global priorities really be set by a cost-benefit analysis?

Oh, God, no. Not at all. We are saying the Copenhagen Consensus is the price list. Essentially we're providing the prices on the social menu of what you can choose to do. No, no, no. Economists don't set the agenda of the world. Hopefully democracies do. You and I. So it's nice to know how much will this cost, how much good will this do. If you go into a restaurant and say, "The only thing I'm going to buy is beluga caviar," that's fine, that's your choice, but at least now you know what the prices are.

I don't know, Bjørn. Cost-benefit analysis seems to be how we got into this trouble in the first place. The oil and automobile companies, for instance, determined that we can pump out this much pollution because it will amount to this much profit, and that's a viable trade-off.

Obviously it's a very different thing when private companies make that choice. Private companies don't care if somebody else has to pay the pollution, and that makes sense.

Shouldn't private companies have a social responsibility?

Well, maybe. If you were a CEO and you had your responsibility to the stockholders, I think it's unreasonable to expect that they would have a huge amount of extra social responsibility. That's what societies have to regulate. That's why we have to make taxes, make environmental regulations, set boundaries, say, "No, you can't do that" or, "Yes, you can do that." Clearly you have to regulate that.

So I would say it's not that way of thinking that's gotten us into trouble. Think back 150 years, when we really started churning out a lot of CO2, and started using coal and then later oil in a massive fashion. If you had been back there then and known about all these problems, how much would you have changed? My sense is you would have said, "I want my kids and grandkids to be well off. I want them to be without diseases. I want them to have a good education and good nutrition." So a lot of good things happened because of fossil fuels. We're now starting to realize that wasn't the case, and we will have to start dealing with it.

But we constantly make trade-offs and ask, To what extent are we willing to let something be a future generation's problem? If we are rational, then we do try to make rational cost-benefit analyses. I'm not saying we must leave some problems for future generations. But it's important to say that we always have. We have never fixed all problems. It's never been like a generation handed over a clean slate and said, "Everything is fixed." Our job here is to fix the most important things, the ones where we can do the most impact, so that we leave the best possible future for our kids. But they'll also have to fend for themselves on some of the problems.

Tom Burke, former executive director of Friends of the Earth, and a former environmental consultant to the British government, called the Copenhagen Consensus "junk economics" in the London Guardian. "In the real world, outcomes are not so easily managed," he wrote. "The truth is that the Copenhagen Consensus is not economics at all. It is politics masquerading as economics."

I'm a little struck by the virulence of calling it junk economics. He's absolutely right this is a political decision, a democratic decision. We're not setting up a coup and letting economists reign. On the other hand, it seems less than smart to avoid, or taking into account, what are the actual impacts of cutting CO2 versus doing other things. I disagree with Burke when he says that's not a relevant input. But you would expect people who argue on behalf of problems that end up toward the bottom of the list to be less sympathetic to the process. If I tell him the things he's suggesting will deliver little benefit for the amount of money we're going to spend, he's likely to say, "We need to do it all."

What do you mean?

He's saying that without solving global warming in its entirety, we won't have a civilization. If this were true -- if we don't spend vast amounts of money right now, then we're all going to die -- our cost-benefit analysis would come out and show, well, he's bloody well right.

But saying we're all going to die is simply unreasonable and quite frankly an unsubstantiated way of looking at the data. I can't see how you can take that out of the predictions of the U.N. Intergovernmental Panel on Climate Change. Having a situation where sea levels will rise a foot is not going to doom civilization, just like a foot of sea-level rise over the last 150 years didn't doom civilization. Sea-level rise will be a problem, yes, but it will not be a catastrophe.

I know I've said it in the book, but I love it so much, allow me to say it again: It's the same sea-level rise that we saw in the last 150 years. If you asked an old woman, who likely lived throughout most of the 20th century, what were the important things that happened, she'll mention world wars and the suffrage of women and maybe the IT revolution. But it's very unlikely she'll say, oh, the sea level rose.

But not all scientists agree that it's going to rise a foot. Jim Hansen, director of the NASA Goddard Institute for Space Studies, and a professor of environmental sciences who has been studying climate change for decades, says that if the temperature rises 3 degrees centigrade by the end of the century, as the IPCC says, the sea level could rise to over 16 feet, and literally swamp the continents. Why should we believe you and not him?

I'm not asking you to believe me. I'm asking you to believe the hundreds of scientists on the U.N. climate panel. And the U.N. climate panel is mediating between a lot of scientists who are saying everything from the sea level is going to decrease -- although not many are saying that -- to it rising a little more than three feet over the coming century. Jim Hansen is the only scientist claiming that you can imaginably see even more over the century.

It's true, and the U.N. climate panel also tells us that, that if you have a sustained warming over centuries, then over millennia you might see a substantial part of Greenland melt. But even if that happened, that would mean a little less than two extra feet per century. That would be substantially more than the middle effort that the U.N. climate panel is talking about but still substantially less than what Jim Hansen is talking about. So, yes, it is true that we could envision three feet. But that is the worst analysis that you can imagine over the next 100 years.

Hansen points to the paleoclimate record and says that when CO2 in the air was at the same level it will be in the coming century if we don't do anything, ice-sheet melt led to a rise of several meters.

What he's basically saying is there's a risk for this to happen. That's absolutely true. There's a risk for virtually everything. But we are not well-guided in making judgments based on worst-case scenarios. I think this is utterly ridiculous. But I'm confronted with this all the time. I consider myself slightly left-wing in Denmark, which is saying a lot. But one of the things that we're incredibly annoyed with was how the military and the right would use worst-case analysis to tell us why we should spend much, much more on rearmament in the '80s during the Cold War. They were saying, "What if the Soviet Union gets everything right and they make a blitzkrieg and make a double war on both sides? So we have to get all this stuff to counter the worst-case analysis." You can't have that.

Obviously we should investigate these issues, and obviously if it suddenly turns out that climate change is a very different order of magnitude, then, yes, that would change the cost-benefit analysis, that would definitely tell us that it might actually be a much better investment to do something right now. But you cannot tweak the arguments by saying, "Oh, I have a worst-case scenario, and maybe this will happen, so we've got to spend all of our money over here."

If that kind of argument becomes reasonable, then you could equally well say that if we don't deal with HIV/AIDS, you'll have a collapse of sub-Saharan Africa, you will have a terrorist nest like in Afghanistan but in all of sub-Saharan Africa. You'll have nuclear potential with all these states. You can easily make up these stories that have very low probability and then say, "Give me all your money to prevent them." I don't think that's a helpful way to have a conversation about what we should be doing.

I'm simply saying, "Don't trust me, just like you shouldn't trust Jim Hansen." We should actually trust the best people on the planet and the actual people who do glaciology, who come together and say, "Yes, there are people out there who say the sea level could rise up to three feet, and there are people who say much less than half a foot. But the most reasonable assumption is that it's somewhere between a half and two feet, and most likely the middle scenario of one foot."

There's a danger of operating out of the best-case scenario too, right? If we don't spend on reducing carbon emissions and spend instead on your other problems, couldn't we be making a drastic mistake?

It's obvious with any choice you can end up making a mistake. I cannot promise that this going to be the right strategy. Mind you, there are reputable peer-reviewed studies out there that show that because we have pumped out so much CO2 in the atmosphere, we haven't gone into a new Ice Age. I'm not saying we should trust that. I'm simply saying that's also a best-case analysis of climate change. But I'm not arguing that either. I'm arguing on central estimates and reasonable spans of those estimates. But yes, there is no guarantee that either if we follow Al Gore or me or any other person that we can ensure ourselves the best future possible. Of course not.

Even if there's a 5 percent chance that Hansen is right, and that sea levels will rise 20 feet, shouldn't we act to reduce carbon emissions now, if only for insurance?

It's true that a lot of people say that Kyoto is an insurance, although it's typically not economists. It's shrewd but it's a drastic misuse of the word "insurance." Insurance means that you pay a small premium and if an unlikely event happens, you get all your money back. If your house burns down, you get the money so you can buy a new house. It amounts to a reduction in the chance of something bad happening. But by buying insurance against climate change, if your house burns down, you don't get anything. You could say you get a door back.

To use my favorite metaphor, saying "insurance" is like talking about lowering the speed on highways. It ensures you a little more safety, but it also has clear costs. And we need to have a conversation of asking, How quick should we drive? Clearly it shouldn't be 250 miles per hour, and likewise it shouldn't be 5 miles per hour. We need to have that sensible discussion. I'm happy to have the discussion of whether it should be 55 or 50, but I think it's silly when people come and say it should be 5.

Do you think Hansen is representative of the environmentalists, journalists and activists you call global warming doomsayers?

I don't know what he is. I've never met him. I'm not going to comment on him in particular. But the idea of only painting the worst-case scenario that's vastly beyond what's considered reasonable when you read the U.N. climate report is not helpful. That's what I'm saying. That doomsayer argument is one that says, "Hey, I'm much more important than everything else."

I take it you think Gore is a doomsayer.

I certainly think Gore is exaggerating, and he's clearly alarmist in the way he presents it. Gore has the best of intentions. I believe that he feels very strongly about this, and he feels that this is an issue to pay more attention to. I think we need to congratulate him on getting the issue on the agenda and taking it away from the people who just say it's a hoax or it's not happening. So that's an important preamble.

But, yes, he's also vastly exaggerating, in the sense of only showing the 20-foot sea-level rise, which, as you pointed out, could be substantiated by scientific voices. But it seems entirely unreasonable to me to leave out the vast majority of scientists who are telling us that it's going to be somewhere between half a foot and two feet over the coming century. I debated the Danish environment minister about "An Inconvenient Truth," and I hate to this day that I didn't pick her up on one point. She said, "Oh, but Bjørn, it's only a one-and-half-hour movie: You don't have time to say everything." But of course you might have time to say what the vast majority of scientists have decided is the reasonable view. And then perhaps say that some scientists even say this could go up to 20 feet. But that's not the sense you're left with in the movie.

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