An Interview with Freeman Dyson...

Dyson, one of the world's foremost physicists, is a skeptic on global warming...

Yale Environment 360: First of all, was that article substantially accurate about your views?

Freeman Dyson: It’s difficult to say, “Yes” or “No.” It was reasonably accurate on details, because they did send a fact-checker. So I was able to correct the worst mistakes. But what I could not correct was the general emphasis of the thing. He had his agenda. Obviously he wanted to write a piece about global warming and I was just the instrument for that, and I am not so much interested in global warming. He portrayed me as sort of obsessed with the subject, which I am definitely not. To me it is a very small part of my life. I don’t claim to be an expert. I never did. I simply find that a lot of these claims that experts are making are absurd. Not that I know better, but I know a few things. My objections to the global warming propaganda are not so much over the technical facts, about which I do not know much, but it’s rather against the way those people behave and the kind of intolerance to criticism that a lot of them have. I think that’s what upsets me.

e360: So it’s a sense you get from the way the argument is conducted that it’s not being done in an honest way.

Dyson: I think the difference between me and most of the experts is that I think I have a much wider view of the whole subject. I was involved in climate studies seriously about 30 years ago. That’s how I got interested. There was an outfit called the Institute for Energy Analysis at Oak Ridge. I visited Oak Ridge many times, and worked with those people, and I thought they were excellent. And the beauty of it was that it was multi-disciplinary. There were experts not just on hydrodynamics of the atmosphere, which of course is important, but also experts on vegetation, on soil, on trees, and so it was sort of half biological and half physics. And I felt that was a very good balance.

And there you got a very strong feeling for how uncertain the whole business is, that the five reservoirs of carbon all are in close contact — the atmosphere, the upper level of the ocean, the land vegetation, the topsoil, and the fossil fuels. They are all about equal in size. They all interact with each other strongly. So you can’t understand any of them unless you understand all of them. Essentially that was the conclusion. It’s a problem of very complicated ecology, and to isolate the atmosphere and the ocean just as a hydrodynamics problem makes no sense.

Thirty years ago, there was a sort of a political split between the Oak Ridge community, which included biology, and people who were doing these fluid dynamics models, which don’t include biology. They got the lion’s share of money and attention. And since then, this group of pure modeling experts has become dominant.

I got out of the field then. I didn’t like the way it was going. It left me with a bad taste.

Syukuro Manabe, right here in Princeton, was the first person who did climate models with enhanced carbon dioxide and they were excellent models. And he used to say very firmly that these models are very good tools for understanding climate, but they are not good tools for predicting climate. I think that’s absolutely right. They are models, but they don’t pretend to be the real world. They are purely fluid dynamics. You can learn a lot from them, but you cannot learn what’s going to happen 10 years from now.

What’s wrong with the models. I mean, I haven’t examined them in detail, (but) I know roughly what’s in them. And the basic problem is that in the case of climate, very small structures, like clouds, dominate. And you cannot model them in any realistic way. They are far too small and too diverse.

So they say, ‘We represent cloudiness by a parameter,’ but I call it a fudge factor. So then you have a formula, which tells you if you have so much cloudiness and so much humidity, and so much temperature, and so much pressure, what will be the result... But if you are using it for a different climate, when you have twice as much carbon dioxide, there is no guarantee that that’s right. There is no way to test it.

We know that plants do react very strongly to enhanced carbon dioxide. At Oak Ridge, they did lots of experiments with enhanced carbon dioxide and it has a drastic effect on plants because it is the main food source for the plants... So if you change the carbon dioxide drastically by a factor of two, the whole behavior of the plant is different. Anyway, that’s so typical of the things they ignore. They are totally missing the biological side, which is probably more than half of the real system.

e360: Do you think it’s because they don’t consider it important, or they just don’t know how to model it?

Dyson: Well, both. I mean it’s a fact that they don’t know how to model it. And the question is, how does it happen that they end up believing their models? But I have seen that happen in many fields. You sit in front of a computer screen for 10 years and you start to think of your model as being real. It is also true that the whole livelihood of all these people depends on people being scared. Really, just psychologically, it would be very difficult for them to come out and say, “Don’t worry, there isn’t a problem.” It’s sort of natural, since their whole life depends on it being a problem. I don’t say that they’re dishonest. But I think it’s just a normal human reaction. It’s true of the military also. They always magnify the threat. Not because they are dishonest; they really believe that there is a threat and it is their job to take care of it. I think it’s the same as the climate community, that they do in a way have a tremendous vested interest in the problem being taken more seriously than it is.

e360: When I wrote my first story about this in 1987, I had to say this is all theoretical, we haven’t actually detected any signal of climate change. Now, people point to all sorts of signals, which are just the sort of things that were being predicted, based in part on the models. They made predictions and they’ve tested the predictions by seeing what happened in the real world, and they seem to be at least in the same direction, and in about the same magnitude, they were predicting. So isn’t that a hint that there is something right about the models?

Dyson: Of course. No doubt that warming is happening. I don’t think it is correct to say “global,” but certainly warming is happening. I have been to Greenland a year ago and saw it for myself. And that’s where the warming is most extreme. And it’s spectacular, no doubt about it. And glaciers are shrinking and so on.

But, there are all sorts of things that are not said, which decreases my feeling of alarm. First of all, the people in Greenland love it. They tell you it’s made their lives a lot easier. They hope it continues. I am not saying none of these consequences are happening. I am just questioning whether they are harmful.

There’s a lot made out of the people who died in heat waves. And there is no doubt that we have heat waves and people die. What they don’t say is actually five times as many people die of cold in winters as die of heat in summer. And it is also true that more of the warming happens in winter than in summer. So, if anything, it’s heavily favorable as far as that goes. It certainly saves more lives in winter than it costs in summer.

So that kind of argument is never made. And I see a systematic bias in the way things are reported. Anything that looks bad is reported, and anything that looks good is not reported.

A lot of these things are not anything to do with human activities. Take the shrinking of glaciers, which certainly has been going on for 300 years and has been well documented. So it certainly wasn’t due to human activities, most of the time. There’s been a very strong warming, in fact, ever since the Little Ice Age, which was most intense in the 17th century. That certainly was not due to human activity.

And the most serious of almost all the problems is the rising sea level. But there again, we have no evidence that this is due to climate change. A good deal of evidence says it’s not. I mean, we know that that’s been going on for

Anything that looks bad is reported, and anything that looks good is not reported.”

12,000 years, and there’s very doubtful arguments as to what’s been happening in the last 50 years and (whether) human activities have been important. It’s not clear whether it’s been accelerating or not. But certainly, most of it is not due to human activities. So it would be a shame if we’ve made huge efforts to stop global warming and the sea continued to rise. That would be a tragedy. Sea level is a real problem, but we should be attacking it directly and not attacking the wrong problem.