We met with Distinguished Professor of Atmospheric Science and Director of the Earth System Science Center at The University of Alabama, Dr. John R. Christy, to talk about the challenge of understanding data used in the climate change debate, and so much more. Enjoy!
Climate scientist Dr. Michael Mann notes climatologist Dr. John R. Christy as a compelling voice on the other side of the climate change debate. Dr. Christy, a pioneer in measuring global temperatures by satellite, discusses challenges to understanding data from satellites, balloons, and terrestrial weather stations. He also examines the impact of CO₂ and the practical problem with climate models driving energy policy worldwide, especially in developing nations. Distinguished professor of Atmospheric Science and director of the Earth System Science Center at The University of Alabama in Huntsville, as well as the Alabama state climatologist, Dr. Christy talks with Dr. Jed Macosko, academic director of AcademicInfluence.com and professor of physics at Wake Forest University.
Our satellite data show the Earth is warming at about a rate of 1.5 degrees C per century. That's a warming that has happened in the geologic past, certainly, and it is a warming rate that is much more gradual than the dire predictions that tend to dominate the media and so on.” – Dr. John Christy
See Dr. Christy’s Academic Influence profile
See additional leaders in earth sciences in our article
Top Influential Earth Scientists Today
Considering a degree in Earth science? Visit Our Earth Sciences Page, where you’ll find the best Earth science colleges and universities, career information, interviews with top Earth scientists, influential scholars in the field of Earth science, great books, a history of the discipline, online sustainability degrees, and more.
(Editor’s Note: The following transcript has been lightly edited to improve clarity.)
Jed Macosko: Hi, this is Dr. Jed Macosko at Wake Forest University and AcademicInfluence.com. Today we have a special guest, Professor John Christy, who according to Michael E. Mann , who we interviewed, is one of the most interesting and reasonable people who stands on the opposite side of the climate debate as Michael Mann. So we thought it would be great to ask Professor Christy about his views and in particular about satellite data that he has been looking at for many years.
So, Professor Christy, great to have you. And could you tell us a little bit about yourself and about that satellite data?
John Christy: Hey, I’ve been looking at climate issues for over 50 years, as a matter of fact, and when we talk about… What I do is I like to build data sets so that we can answer questions about climate, what it’s doing and maybe why it’s doing what it’s doing. And so one of those big data sets that we built was from satellites, where satellites can take microwave emissions from oxygen in the atmosphere, so we could tell the temperature of the deep layer of the atmosphere. This is from the surface to 15,000 feet or so, or 35,000 feet. And this deep layer is important because all the atmospheric things happen there.
Our satellite data has been around a long time, and we have made several adjustments to it. And in the latest paper that we published just a couple of years ago, it indicates that the UAH satellite data is the one that agrees the best with independent measurements there are. So notions that the satellite data have been debunked are news to me because we have been publishing all along and providing adjustments and improvements through time.
Jed: So it’s truly news to… You mean, nobody told you that they feel like your data was debunked? ’Cause that’s what Michael Mann said on his interview.
John: I think these are kind of urban legends that if you go to the peer-reviewed literature, and this is where we published in the International Journal of Remote Sensing, just two years ago, the latest and most comprehensive analysis of all the different data sets, and our satellite data sets, the UH one, did extremely well in comparison with independent data that’s taken, for example, by balloon releases.
Jed: So if you had to play devil’s advocate, what would you say would be the weakness of the satellite data? Is it that it’s not complete enough? That the error bars are too large? That there could be something not accounted for in the models of how you then interpret it? Or if you just wanted to step on the other side and be the devil’s advocate, what would you say?
John: I’d say what we encountered is that sometimes these sensors that are on the spacecraft are not perfectly stable, and so you have to be careful to make sure that you inter-compare with other satellites already in orbit, to make sure that they don’t go astray. And in one case, two satellites went astray basically in the same way, and so we had to backtrack and fix those kinds of things, so it’s not knowing precisely the characterization of the instrument once it’s in space.
Jed: Okay, now, if those things were off, would it be very strange that they correlate well with the hot air balloon or, I mean, weather balloon data?
John: No, if they were off, you would see the difference between the balloon measurements, and so that’s why we use these, and balloons are completely independent from the satellite measurement, so it’s a good check against how we’re doing.
Jed: Okay, so even as devil advocate, you can’t really say that that one problem would have caused a problem because you have good correlation with the weather balloon data. So, yeah, I’m drawing a blank as to why somebody would say your data has been debunked.
Now, what would happen if your data was true, but also the data that Michael Mann looks at, the hockey stick, everything like that, is also true? Is there any way to reconcile those?
John: Oh, well, when you’re talking about data from paleoclimate records and so on and the satellite data over the last 41 years, those are two kinda different data sets. I think what we do in building data sets like this that are truly global is these are great tools and information to check theories with, and so the thing that we do the most is we check the theories that people come up with about the climate, and mainly those theories come out in climate models.
And so what the climate models show is that the world is warming much more rapidly than the actual data actually show. And so this is a real important aspect of satellite data. But it’s not just our satellite data, we use data from the balloons, like I said, we use data from weather centers around the world that create global data sets, so we have multiple evidences that these models, 100% of them, by the way, are warming the planet more than it actually is.
Jed: Okay. Well, I can see that the models, even 100% of the models, are over-predicting the warming, I can see that, but that doesn’t mean that the Earth is not warming up, and that other things… ’cause, I mean, I know they used to call it global warming, now they call it climate change. I know that that was a strategic decision because some parts of the world might get colder even in their own models, so it’s not really like everything’s warming up. So all that to say that you would agree that even if 100% of the models are over-predicting warming, there could still be some huge problems with how much CO2 we’re putting into the atmosphere.
Okay? You would agree that that’s a possibility, right? Wouldn’t you agree that?
John: Well, you say that’s a possibility. An asteroid could destroy the earth tomorrow, that’s a possibility too, but what we have done in many, many ways is examine these claims about things getting worse, and they simply are not, whether you’re talking about hurricanes or tornadoes or floods or droughts, or heat waves and so on, we’ve examined those trends and they just are not significant one way or the other.
Although maybe tornados are significantly down, but that can change, I think. So we test those very claims you’ve mentioned… The world… Our satellite data show the Earth is warming at about a rate of 1.5 degrees C per century. That’s a warming that has happened in the geologic past, certainly, and it is a warming rate that is much more gradual than the dire predictions that tend to dominate the media and so on.
Jed: So Michael Mann said he enjoys talking to you. If you told Michael Mann, in a friendly conversation over drinks, that all the things that are in the media about how there’s more hurricanes and more forest fires have been shown to be wrong, would he say, “Yeah, I know, the media gets this all wrong. Of course, it’s not statistically significantly more, but if the world is warming up, and I think it is,” of course he thinks it is, “then there would be more power in the hurricanes, so we should expect to see more hurricanes in the future, even if we’re not statistically noticing the trend now. Our statistics are not great, so it might take a lot of hurricanes before it’s a statistically significant, and yet we know it’s gonna happen because the oceans are warming.”
Is that that kind of approach he might take, or would he disagree with you? He says, “No, it’s statistically significant. There are more hurricanes.” What would he say?
John: I don’t think Michael would say that there is a statistically significant change in hurricanes, because it’s just not true, the data are pretty clear on that. But this notion that they could get worse, that’s a very popular notion. So we look very carefully at those kinds of thing and say, “Well, in the time that we have had an increase in carbon dioxide, which is true, and therefore there is a greater radiated forcing from carbon dioxide, that’s true, carbon dioxide can’t not be a greenhouse gas, it’s gonna absorb at the 15-micron band for sure, we look and do not see the response that people claim should be there.” We look at the response in many parts of the climate system and don’t see the response that is hypothesized to occur, and that’s the guts of science. You make a claim, let’s find some independent data to check that claim and determine if that claim is true or false.
Jed: Alright, so another argument is, “Okay, fine, we’re predicting more warming than there actually is. Okay, but on a balance, maybe it’s gonna help people do better about pollution and things and hurting the environment, making organisms go extinct, all kinds of bad things that humans have done to this planet we live on.
Isn’t it okay that maybe our models are a little bit over-blown, or is there a real negative side to believing in those models and putting those in the media?”
…people are not dying because of this tiny bit of warming that we see, and so that's where the policy really comes in, is when you try to make energy policy based upon climate models that are really exaggerating what's going on.” – Dr. John Christy
John: Well, there is an extremely negative side, and someone who has lived in Africa, I can tell you that without energy, life is brutal and short. So if you want to condemn hundreds of millions of people to poverty and difficult lives, tell them that they can’t have energy, and right now, the way it is in the real world is that carbon is the fastest and safest way for these impoverished folks, especially, to arrive at the energy access they need for their improvement of life.
If you really care about people living longer and better, like we really care about, then you would want that to happen. So these energy policies that are based upon these rapid climate models are just not based on the right kind of science, and the rates of warming now that we actually see are not alarming. I mean, people are not dying because of this tiny bit of warming that we see, and so that’s where the policy really comes in, is when you try to make energy policy based upon climate models that are really exaggerating what’s going on.
Jed: Now, in a scenario that you just described, I could kind of imagine, “Okay, we’ll make a new Paris Accord that says if you’re in a developing country, you can still burn fossil fuel. If you’re in a more modern country, you have to just do solar and wind and nuclear and all these other things, because even though one guy’s model, John Christy’s model, says it’s not a big deal, we gotta be careful. We know that there’s more greenhouse gas. We know there’s more CO2. And you agree that there’s more. That might be bad, that might be really bad, and even if his models don’t show it, we can’t just trust that, we gotta be careful here.”
So would that be a good strategy? Would you support that kind of a strategy?
John: Well, first of all, I don’t have a model, these are real data that we’re talking about, that I’m talking about, the real data that disproves, that invalidates basically what models are showing, so just separate that. And another thing is that we can pass all kinds of regulations at the United Nations level or this level, but the impoverished world is going to do what it’s going to do. And we can just see the evidence and the rising amounts of CO2 in the atmosphere right now, and we’re not gonna stop the fact that they want to have longer and better lives just like we do.
So is it our role to say, “You can’t do this”? And I don’t think morally we have that leg to stand on. Now, there are a lot of pollution problems, and you touched on this earlier, that when you talk about water pollution and air pollution… And carbon dioxide is not an air pollutant, by the way. And so you’re talking about the aerosols that cause various diseases or the water pollution that kills millions of people around the world today, these are points that we can address and we do know how to fix, and those are the things we should focus on right now.
Jed: I agree, we should definitely focus on the things that are killing people. That’s really true. You said that people in developing worlds are not gonna listen to what the UN says ’cause they’re gonna want a better life. What I was saying is, “Well, let’s make a Paris Accord or whatnot that tells the developing world you can use fossil fuel. Go for it. We want you to have longer healthier lives. But the rest of the world, we’re gonna really try to not do carbon emissions and sequester the carbon and do all that kind of stuff.”
Would you support that kind of a policy?
John: Only if it made sense. Solar and wind do not make sense. I just read a report from Washington State how they cannot go to any more wind because these things are causing such terrible problems in load balancings and so on with that state’s electricity grid, so solar and wind will not solve it. Nuclear could, in terms of emissions, nuclear is a big way to provide that type of energy, that energy on demand that a current economy, a modern economy needs.
Unfortunately, in this country, the red tape is so deep to try to get a nuclear plant built, that it’s just really tough. I asked Georgia Power and Southern Company what it’s like to build the Vogtle plant out there in Savannah right now, or near Savannah. So we’ve got a lot of problems with nuclear that aren’t physics problems, red tape problems.
Jed: Alright, well, this is fascinating. I really do appreciate you following up on our interview with Michael Mann and giving us your own thoughts. Thank you for taking the time today. It was truly a pleasure. Thank you, John.
John: Okay, my pleasure.
Visit our full library of interviews with experts, scholars, and living legends.
Or get tips on studying, student life, and much more with a look at our Student Resources.