MOT: Why do you believe the current warming estimates are overly exaggerated?
Spencer: I think climate modelers are overestimating global warming in their models, because when they built the models, they put in the relationships, which were based on observing weather and climate variability in the real climate system, and those relationships I believe were misinterpreting the difference between cause and effect.
For example, between temperature in clouds, they were assuming causation in only one direction and when they put that in the climate model, they end up getting a lot of warming. If they would’ve assumed the causation would go in the other direction, it wouldn’t have happened, so even though it sounds like a basic thing, confusing cause and effect in the climate system, I think this is going to be an emerging issue that throws a lot of uncertainty into the predictions of a lot of global warming in the future.
MOT: What are the factors controlling over the climate system?
Spencer: There’s a lot of factors controlling the climate system obviously, but the one everybody knows about is the sun, right? That’s the energy source for everything. Once the sunlight gets here and warms the surface, then all kinds of strange things happen. Cloud formation, which not only cools things by reflecting sunlight, but it also warms things, because it has a greenhouse effect, that traps in infrared radiation, same with water vapor, which is evaporated from the surface. Actually what mostly cools the surface of the planet is the evaporation of water vapor, and that has a greenhouse effect. Rainfall is a way that water vapor is taken out of the atmosphere so that reduces the greenhouse effect and all of these different components are interacting in complex ways, ways that we don’t completely understand. And even if we do understand how they work on average, in global warming, what we’re interest in is not the average, but how everything will change as we add carbon dioxide, so that adds another layer of complexity into the problem.
MOT: How sensitive is the climate to manmade greenhouse gases?
Spencer: Some people like NASA's Jim Hansen thinks the climate is very sensitive to manmade greenhouse gases. In fact, he now thinks that what we already have put into the atmosphere is too much and we have to start removing it, and of course we’re still adding carbon dioxide to the atmosphere. I think the climate is fairly insensitive to our greenhouse gas emissions. I think most of what we’ve seen in the way of global warming is due to internal natural processes. So there’s a wide range of opinions but I would say the majority of opinions is that the system is very sensitive, but a minority of us scientists, usually called skeptics, is that the system is not very sensitive to the CO2 that we add to the atmosphere.
MOT: How do you know that?
Spencer: I don’t know that! What I’m trying to do is convince the scientists that are so sure they see evidence of a sensitive climate system, and that global warming is going to be serious, I want to show them that look, all I have to do is interpret things a little differently and I come to the opposite conclusion. And they are not looking in the direction they should be. They can’t see the forest for the trees basically.
MOT: And how sensitive is climate to the natural factors, such as variations in clouds and precipitation?
Spencer: Climate sensitivity is a funny thing, because it can be sensitive on a short timescale, but insensitive on a long timescale. Let me give you an example; during an El Niño event, the system warms up quite a bit, okay? That’s quite a lot of climate variability, but I think the climate system then has mechanisms that fights against the warming and keeps the warming from being as strong as It could be. All we have to do is look back in history; we had a medieval warm period that was clearly very warm, a thousand years ago, Vikings were farming in Greenland. Hundreds of years later, we had the little ice age. Clearly not a good time for humanity. So it’s obvious that there are big natural changes in the climate system, and I think it raises the interesting question of what is the normal temperature of the earth, I don’t think there is a normal temperature of the earth, I think it’s a philosophical question, not a scientific one.
MOT: Why is the greenhouse effect maintained at it’s current strength?
Spencer: Some people, probably most climate modelers, think that the greenhouse effect is maintained by the temperature of the surface, which in turn is maintained by sunlight coming and warming the surface. So usually they say, and If we add more carbon dioxide to the atmosphere, that’s going to warm the surface more and put more water vapor into the atmosphere, since water vapor is the main greenhouse gas, it’s gonna make global warming even worse. Well they’re only telling half the story. The other half is that there’s a limit to how strong the greenhouse effect gets in the atmosphere naturally, even without us. There’s a limit and what limits the greenhouse effect is the precipitation systems, because that’s the only way for water vapor to get out of the atmosphere is through precipitation. So what we really need to know for global warming is how do precipitation systems change in the way they take out water vapor and until we answer that question, we don’t have an answer right now, I don’t think we can predict global warming with any certainty at all.
MOT: The models usually assume that cloud variability is the result of temperature. Is the case so?
Spencer: I think there’s a fundamental misunderstanding amongst climate modelers, when they build their climate models based on relationships they see looking at real climate data. When they look at real climate data, they’ll see how clouds change from one year to the next, they’ll see how temperature changes from one year to the next. And when they relate those two, they’re assuming that the temperature change caused the cloud change. But they’re missing the effect that some of the cloud change caused the temperature change and to the extent that they are missing the causation in the other direction, it will always look like the climate system is very sensitive, in other words positive feedbacks, it will always look like there are positive feedbacks in the system, when In fact it’s because people are misinterpreting the roles of cause and effect in the climate system.
MOT: How can so many modelers be wrong?
Spencer: How could so many medical researchers be wrong about peptic ulcers, which for decades doctors thought was caused by spicy food or a stressful life and then two Australian doctors came along and claimed that they thought peptic ulcers were due to a bacterial infection and they were ridiculed by the community for ten years, because of their belief. Two doctors. Now they’ve gotten the Nobel prize for their findings. And that’s an easy problem. That’s the stomach, everybody has a stomach, millions of people have ulcers, it can be studied. Here with the climate system and global warming, all we’ve got is one experiment going on, we can’t do an experiment in the lab, we have a real world experiment going on and we’re all part of it. And there’s no way to test global warming theory. We just have to see what happens, so I’m not surprised at all that most of the scientists can be wrong on this issue.
MOT: What do we know about the reasons for climate variability?
Spencer: At the present state of climate science, I think we know very little about what causes natural climate variability. We know that it happens, we know that el Niño’s happen, we know that la Niños happen, we know that theirs is such a thing as the pacific decadal oscillation, which seems to switch every 30 years or so and changes the general circulation of the atmosphere, but we don’t know why these things change. I would call them just different modes of chaos, chaotic behavior of the climate system, but we don’t know how to predict chaos, we don’t know when these events are going to take place. If a climate modeler needs to model the climate, he can’t put things in that he doesn’t understand. But what we do understand is that carbon dioxide is a greenhouse gas and we are putting more of it into the atmosphere and so all of the scientific focus has been on carbon dioxide and not on natural climate variability, partly because we don’t understand natural climate variability and yet that may be the answer why we’ve seen warming in the last 100 years, it might be in the realm of natural climate variability and not in the realm of manmade carbon dioxide.
MOT: Are there peer reviewed studies which have ruled out natural climate variability as the cause of the recent warmth?
Spencer: I’d like to point out that there’s never been a paper published that has ruled out natural climate variability for most of the warming we’ve seen in the last 100 years. All researchers do is show that if you build a model and force it with extra CO2, you can explain the warming just based on that, but it could be that there are better explanations or easier explanations. It’s the usual case of alternate hypothesis and I don’t think enough people have looked at the alternative hypothesis, everyone is focused on just carbon dioxide.
MOT: How big is the share of man and how big is the share of nature in the warming according to you?
Spencer: Well that’s the big question; how much of the warming is due to mankind, versus nature. Probably a majority of climate scientists think it’s manmade, but they can’t give you a percentage, because they really don’t know. I believe it could easily be mostly natural, and I don’t think I would put a percentage of it because I don’t know enough, none of us knows enough to put percentages on this, but I think it’s entirely possible (that) most of the warming is natural.
MOT: Why have the natural causes not been accepted as a source for the warming?
Spencer: There’s a lot of reasons why natural causes of warming have not been investigated very much, and they all have to do with not science but with human nature. In order for us to study global warming as a problem, we have to convince the United States congress to give us money, to study the problem, and if there isn’t a problem, they’re not gonna give you money. So the problem is: we’ve got the threat of manmade global warming so that is what most people are funded to study. Not very much money goes into research, none that I know of, to look into possible natural causes of climate variability of global warming, which I think is a mistake. So the deck of cards is stacked against natural climate variability from the very start, and the very start is the funding sources of all of our research.
MOT: What do you think about the role of the sun?
Spencer: There are few people out there that think there’s a sunspot control of the climate in some way and I think that’s possible. It could be one of the players in fact, but I personally don’t think it’s a major issue. I’m more convinced that it’s just internal chaotic behavior in the climate system, but it may be that all of these things are happening together, it might be partly solar, partly interior chaotic behavior In the climate system, and a little bit of manmade global warming in there too.
MOT: What do you mean by the expression that precipitation systems work as an excess air conditioner or thermostat?
Spencer: Well, the way I like to demonstrate the influence of precipitation systems is that all of the air that we breathe within a matter of days, most of that air is going to be sucked up into a precipitation system somewhere, a certain amount of water vapor is going to be taken out, because that’s what precipitation is, it’s condensed water vapor, and the remaining air is going to be exhaled by the precipitation system, into the rest of the global environment. So air is constantly being recycled by precipitation systems, like an air conditioner and all of the rest of the year, it’s humidity content, it’s cloud content, that’s what determines the earths greenhouse effect, so ultimately precipitation systems are what control the limit of the earths greenhouse effect, and I think even a lot of researchers don’t realize that fact, and guess what part of the climate systems we understand the least? The precipitation systems.
MOT: How do you know that this air conditioner exists?
Spencer: We think we’ve actually observer these precipitation systems behaving in a thermostatically controlled, air conditioner manner. We studied six years of tropical data from a variety of satellites and a variety of instruments, and they all told a cohesive, consistent story: when the tropical atmosphere warms up, within a matter of days the precipitation systems there, taken on the whole, this is averaged over the whole tropics of the earth, taken on the whole the precipitation systems, started producing less cirrus clouds coming out of the top of them and since cirrus clouds have a very strong greenhouse effect.
What that did is allow more infrared radiation to escape to space, which we also measure and this is basically a support to Dick Lindzen's infrared iris theory, which he had for the way precipitation systems behave during warming and this is a thermostatically controlled air conditioning thing, it’s a natural cooling system that comes in when the atmosphere becomes too warm and we’ve actually documented behavior that behaves that way.
MOT: Why did you study this phenomenon in the tropics and the troposphere?
Spencer: Well of course the troposphere is where all the weather happens. Above that is the stratosphere, where there isn’t a whole lot occurring except for the ozone, but down in the troposphere where all the weather is occurring, the reason why researchers tend to focus on the tropics is because things are simpler in the tropics. The rotation of the earth doesn’t come into play so much in the tropics, and basically all you have is more moist air rising and precipitation systems and then clean air sinking elsewhere it’s a simpler system to study, and since the whole climate system involves this convective overturning, a good way to study to study just the convection is to go to the tropics, because that’s where it’s more cleanly visible.
MOT: And now, what are your conclusions from these observations?
Spencer: The immediate conclusion of this observation is that there are natural modes of climate variability in the tropical atmosphere, which naturally cool the climate, in a way that climate models don’t contain. In fact, climate models do exactly the opposite, so one of the conclusions is; maybe the climate modelers need to look more carefully how they program the climate models, because they don’t produce this behavior, well if they don’t produce this natural cooling behavior, I wonder how many other natural cooling behavior there are out there that they aren’t aware of.
MOT: The question is about the negativeness or positiveness of cloud feedback, and now, if the feedback that was supposed to be positive turns out to be negative, how crucial is this finding?
Spencer: Virtually all of the disagreement in the science community about how bad global warming is going to be is related to feedbacks. Whether the changes in clouds and water vapor will amplify the little bit of warming from the extra carbon dioxide we’re putting into the atmosphere or whether they will change in such a way to mitigate that warming, to reduce it greatly. Either one is possible and we’re really not sure. Most climate modelers think that the climate system operates in the realm of positive feedback, and if the feedback gets too positive, you start running into things like tipping points where the climate system becomes unstable, so you can sort of see why some researchers, some climate modelers are so worried about global warming, that there’s a possibility that we could go into an unstable climate. I think that the fact that we have not understood feedbacks any better now than we did 20 years ago, suggests that there’s something we’re missing, and I believe that what we’re missing is an understanding between cause and effect, when we look at natural climate variability.
MOT: How do precipitation systems change in response to mankind’s small additions of greenhouse gases to the atmosphere?
Spencer: Well we know that the carbon dioxide that we’re putting into the atmosphere has associated with it an additional amount of greenhouse effect. We know that carbon dioxide is a greenhouse gas, greenhouse gases warm the lower atmosphere, so they’ve got to have some effect. But the role of precipitation systems I think could be to compensate for that, in other words, if CO2 produces a bit more greenhouse effect, I think precipitation systems might change a little bit, to reduce their portion of the greenhouse effect, remember, most of the earths greenhouse effect, at least 90% is due to water vapor and clouds, which are mostly under the control of precipitation systems. So precipitation systems control most of the earths greenhouse effect, so we need to understand that part and how its’ gonna respond to this little bit of warming we get from the CO2 and I don’t think we understand that natural part well enough to know what’s going to happen but if I had to guess, I’d say I think they’re going to compensate in an air conditioning way to reduce the warming, which would be a negative feedback.
MOT: Can we rely on the earth’s air conditioner to switch on when things get too warm?
Spencer: Well, in nature’s air conditioner like I like to call it, precipitation systems are constantly operating. The air that we breathe is continuously being recycled. The air that we breathed a few days ago was inside a precipitation system somewhere and then it coursed through the upper troposphere and sank back down and then it’s down here where we breathe again, so precipitation systems are always acting in this thermostatic way, now the question is will they continue to operate in that way, I think they will, but there’s no way to prove it. So everything I’ve said, I’m not absolutely sure of. You know, these are different theories and we’re always going to be faced with uncertainty, we’re gonna have to make policy decisions in the face of uncertainty, when it comes to global warming. There’s just no way around it.
MOT: Now what is your message to the modelers?
Spencer: I think the modelers need to start looking in places they haven’t looked yet, specifically the role of natural processes In the atmosphere, that for instance cause clouds to change, because to the extent there are other things in the climate systems that cause clouds to change, besides just surface temperature, then they are misinterpreting what’s going on in the climate system and they are programming their climate models with relationships, which they think are reflective of reality, they’re really not. And it’s interesting that all 20 of the major climate models have a climate sensitivity that is higher than even the modelers admit we see in the real world, in the real atmosphere. They’ve taken measurements over 10-15 years from satellites and come up with their best estimates of what the feedbacks are, which means their best estimates of what the climate sensitivity is and it is less sensitive than all of the climate models. And I think this confusion between cause and effect when they built the models is the underlying reason why, when they put observer relationships into the models, the models produce too much warming and it’s because they’re mixing up cause and effect.
MOT: Could this thermometer effect explain that temperature has been almost flat during the past seven years?
Spencer: There’s all kinds of potential reasons why we haven’t warmed, why the globally average temperature hasn’t warmed in the last 7 or 8 years. One possibility is that the thermostatic mechanism with precipitation systems is operating and is correcting for the extra warming that we are expecting from the carbon dioxide, but we are not seeing it because the precipitation systems are changing the earths greenhouse effect continuously. So that is one possibility or another possibility is that clouds have changed somewhat because of a change in circulation of the whole global atmosphere. The pacific decadal oscillation changes sign every 30 years or so and some people think that it has recently switched again and if it has we could be in for a period of cooling, because that’s the way the pacific decadal oscillation works.
MOT: What do you think about the possibility of a catastrophic manmade climate change?
Spencer: I think the possibility of a catastrophic manmade climate change is very, very small. But that is a statement of faith on my part. I cannot prove it. And climate modelers that believe that there will be a catastrophic climate change, can’t prove it either. So it’s a matter of faith ultimately, how much we believe predictions of global warming in the future. I’m not worried about it and I’m not worried that my children are gonna be affected by it or their children. I don’t think it’s gonna be a problem.
MOT: But shouldn’t we anyway do something, just in case, as a life insurance?
Spencer: If there was a way to reduce our carbon dioxide emissions substantially, by 50%, 60%, 70%, without it being too painful, it would be stupid to not do that. The trouble is, is there is nothing humanity can do from a practical standpoint to greatly reduce carbon dioxide emissions, because everything we do depends on energy and the only affordable, abundant source of energy we have right now is fossil fuels. You can add solar energy to help a little bit, you can add wind energy to help a little bit, but the demand for energy in the world is growing so rapidly there’s no other way to satisfy it than with fossil fuels, so we don’t have a choice. Using the insurance analogy is not a good analogy, because the insurance policy is way too expensive and it may not even pay off anyway, because it may be that we’re not the ones responsible for global warming, It could be Mother Nature.
MOT: But if there is a catastrophe going to attack us?
Spencer: If we knew there was a catastrophe coming, then we would probably do everything we can. The trouble is that we can’t do anything, short of giving up everything in the way of modern lifestyle, the way we travel, all of the electricity we use for heating and cooling. That’s a big IF – we don’t know if there’s a catastrophe around the corner. And since a catastrophe is by definition “very bad” you would think that we should do whatever we can. It’s just that there is nothing we can do that’s going to make any difference, that’s why I don’t like Al Gore’s statement at the end of his movie “An Inconvenient Truth”, where he says; we can fix this problem, if we switch to compact fluorescent light bulbs, buy hybrid cars and turn the lights off when you leave the room. Well, even if everybody in the world does that, CO2 emissions are gonna continue to rise anyway, because these are very minor components of all of the energy that we use, so I think there’s no way around it until we find a new energy source of some kind that we can’t currently envision, we are stuck with fossil fuels.
MOT: Many people see the climate change phenomenon as a new religion. What do you think?
Spencer: I think there are a lot of religious aspects of this worrying about global warming. I think people need something to worry about, and saving the planet is as good a thing as any to worry about I suppose. Some people have drawn parallels between worry over the environment and religious beliefs and religious customs even. This question is not the best one to ask me I think, except in the general sense.
MOT: If you’re sinful, mankind, if you don’t stop this sinful consuming, I, Mother Gaia will come and punish you with a high tide.
Spencer: I think it’s very interesting that some environmentalists don’t look at mankind as being part of nature, because I do. For instance I use the example of trees; the existence of trees on the earth changes the atmospheric composition of carbon dioxide, it changes what kind of vegetation grows on land, because the trees steal sunlight from vines and shrubs and flowers that could grow where the trees are. Probably changes the climate system, just the existence of trees, so why is it that trees are allowed to change the climate system, but humans aren’t. Philosophically it doesn’t even make sense!
MOT: What do you think about the movie of Al Gore?
Spencer: I think Al Gore’s movie was very convincing, for people that know relatively little about climate change and the issues involved in climate change. I think the biggest misconception you get form Al Gore’s movie is that all of the natural things he showed happening, whether it’s ice falling off of glaciers and crashing into the ocean, or whether it’s droughts, or whether it’s flood, or whether it’s hurricanes, or whether it’s tornadoes, everything he showed happens naturally, even without mankind. And yet he makes it look like he implies that all of these things are actually the result of mankind. Of course that’s not true, the theory is that maybe we’re making things worse and there isn’t even much evidence for that, so I find the whole movie to be very misleading, but misleading in a very effective way.
MOT: It has been claimed that there are no peer reviewed scientific articles that oppose the a manmade source of global warming. How true is that?
Spencer: I think that’s totally false. There are articles out there that have said; unless we understand this thing, we can’t predict future temperature ,we can’t predict global warming. Those kind of papers are usually ignored, they are part of the peer reviewed literature, they are in the minority, but they are out there. And in fact all it takes is one scientific finding published in one paper to completely overturn an entire scientific body of thought.
MOT: Another claim that is generally used is that the science is settled. According to your experience, what is the number of skeptical or optimistic scientists within the community and how is their number developing?
Spencer: I think in the realm of climate researchers, probably a majority, over 50% of all climate researchers believe that manmade global warming is a serious problem. Maybe they disagree with how much warming we’re going to get, but that it’s a serious problem and it needs to be addressed. Now amongst meteorologists, which I was trained as a meteorologist, which is just weather, not climate. We know more about how things work in weather, precipitation systems for example and clouds, we have a better understanding of the nuts and bolts of the climate system. I think amongst those people, meteorologists, there is much more skepticism about global warming being a serious problem. That’s my experience. Probably I would say more than half of meteorologists that aren’t climate researchers are skeptical of mankind's influence on climate.
MOT: And the climate warming debate, is it settled or is it over as it has been claimed also?
Spencer: Well certainly the debate isn’t all over on global warming and the only people that say it’s over are politicians and celebrities. You won’t hear the scientists say that it’s over, because they know its’ not over. Even the people that think there's going to be a lot of global warming have disagreements about how much a lot is. So I think the debate is going to continue, I think there are more people like myself on the skeptic side that are speaking out now, and it may get more heated in the future, especially if interesting things happen in the climate system. For instance, if it continues for several more years without warming, people are going to be very distrustful of these predictions of catastrophic global warming.
MOT: And at last, what kind of a shill for Big Oil you are?
Spencer: Some people think I’m a shill for Big Oil, and I’m not. I’ve never gotten money from Big Oil to do anything, they’ve never even asked me to do anything. Nevertheless I appear to be a shill because I’m supportive of what oil and coal have brought to humanity in the way of longer lives and all the conveniences we have. Everything requires energy. So no, I’m not a shill for Big Oil, and I don’t plan on being one in the near future.
MOT: Thank you.
Toimittaja Martti Backman
- Manuscript In English
- John Christyn haastattelu Alabaman yliopistolla, kesäkuu 2008
- Mikko Alestalon haastattelu, syyskuu 2008