Christy’s Data-Based Climate Science

Climate Realism in Germany interviewed John Christy last year, as shown in the video above.  For those who prefer reading, I provide a lightly edited transcript below in italics with my bolds and added images.

CR:  Professor John Christy, thank you for joining me.
Can you please tell me a bit about your background and who you are?

JC: Okay i was actually born and raised in California, the other side of the United States in a desert area of Fresno county. I went to school as a math major and then later as an atmospheric science major and received a PhD in atmospheric sciences from the University of Illinois. And I’ve been at the University of Alabama in Huntsville ever since I graduated here 35 years ago.

CR:  So you’re you’re a researcher. Are you teaching or you do both?

JC: I do both research and teaching. I spend most of my time primarily on the research.
It’s a field with research where you view data. My research is mostly on data analysis in terms of trying to build climate data sets from scratch. It’s so that we can have a record of how they were built and what they actually mean.

CR:  You’ve been involved with a measurement of the of the climate so to speak, the measurement of temperature and moisture, water vapor and so forth. And you’ve actually been one of the pioneers in doing so. Can you tell me a little bit about how it all started and how it evolved until now with the
satellite data?

JC:  All right. Around 1988 or so there was a lot of information coming out stating that the globe was warming rapidly, and congressional hearings were held. But we knew that those data were based upon ground stations which were pretty sparse and not very well calibrated. And my colleague Roy Spencer being a satellite expert, we were able to take data from NOAA satellites that orbit the earth from pole to pole. They see the entire earth and take a deep layer of the atmosphere and get the temperature of that rather than something just right at the surface. We actually were able to measure the temperature of the entire troposphere from the surface to about 10 kilometers in altitude. That’s the bulk of the atmosphere, so if you know the temperature of that, you will know if there really is a change in what’s going on.  We began that study in 1989 and published in 1990 and are still carrying on with satellites today.

CR:  So your work with Roy Spencer, are you still colleagues or do you work together? How does it play out?

JC:  Yes I’m the Director of the Earth System Science center here at the University of Alabama in Huntsville. And Roy is one of my chief scientists, so we work together right here in the same building.

CR:  So you you collect the data from the satellites but you also use weather balloons. Is that still a thing with available balloons now we have the satellites?

JC:  Oh weather balloons can do something satellites can’t. Weather balloons take precise temperature and humidity and wind readings at very discrete levels. Satellites see big layers, and so if you want to get the fine resolution in the vertical, you do need balloons. So we will continue to have balloon data.

CR:  So how does does it work with balloons in practical terms? How often are they released and how how big a network do you have for people who release it?

JC:  Well of course balloons are only released where people live and so that’s going to be at best a few islands out in the oceans and various places on the continents. United States and Europe and China have lots of balloon data but most of the rest of the continents do not. So we do have kind of a sparse network of balloons and that’s a little problem. So in comparing with satellites we take what the satellite sees at that same point where the balloon was released. And so we’re able to do a real direct comparison between the two.

CR: How long does the data go back for the balloons? Are they the same as the satellite record?

JC:  The satellites start in late 1978, while the balloons go back about 20 years earlier, about 1957 or so. It’s enough coverage to where you have some sense of a global temperature.

CR: So would you say that the land-based weather stations are not really a good data set to conclude anything about the climate, like for the trends? Or are they useful for us to some extent?

JC:  In terms of climate for long-term changes, the surface data set has a lot of problems. The great problem is that much of the major continents are not observed. There were only a few stations in Africa and South America. These are big continents, and lots of Asia is missing in the early part of the 19th century. So you don’t have much information there to make a temperature measurement for the globe.

CR: So the satellite doesn’t really come to play until the 1980s. Does that mean that we cannot really trust the data from from from prior that period?

JC:  Well a lot of people try to work out the problems of the surface data set, and so we have some reasonable results from what they show. I believe that they probably exaggerate the warming over land because of the fact the weather stations are established where people live. And over the last 150 years people have created roads and parking lots and buildings and so on, and those affect the surface temperature measurements by warming them up a bit.

CR: So in the last 150 years the globe had been warming around one degree Celsius. Could it be less than that?

JC:  I think it could be less than that but not too much, maybe a quarter degree less.

CR: So so you can still use the data to some extent?

JC: Yes I think what you see in the surface temperature data set is a very clear rise from 1910 or so to about 1940-1945, and then a leveling off until about 1970-75 and then a rise since that time. That’s probably a pretty good representation of what actually happened on the global climate.

CR: With some degree of uncertainty I guess?

JC:  Yes and there is a big uncertainty. You know I like to build data sets to study the climate to tell us what the climate has done. The real big question is: Why did it do so? You can ask the question:
Why did the earth warm from 1910 to 1945? It certainly wasn’t due to humans. So it would indicate that, I like to say Mother Nature, or natural variability can cause the global temperature to change.

CR: And that happened a bit before in the past. Do we have enough coverage of the world? I know that satellite data doesn’t include the arctic region. Is that correct?

JC:  The satellite data we use to have a good enough and dense coverage for the polar regions extends to about 85 north and 85 south. So that’s a very tiny bit of the polar cap. That is not measured well enough, and so we don’t include that. But 99 percent of the globe we have enough coverage to get an accurate idea of what’s going on.

CR: Would you like more satellites?

JC:  Well we can always use more satellites, mainly so that we can intercalibrate between them. You can imagine the satellite orbits pole to pole as the earth rotates underneath it and so the satellite has about 14 orbits per day that it sees everywhere around the earth. So it sees very systematically. One of the best things about a satellite is it uses one thermometer and it measures the globe systematically every day, and so we get a nice geographical coverage. And we do not have to worry about the fact that in surface temperature measurements you might have a spot here a spot there and then the station goes away and another one comes in or gets moved and so on. We don’t have those issues with the satellite data.

CR: But I’ve been reading about satellites when you launch them they have to be calibrated once in a while. Does that give some place for error in the measurement or are they very accurate?

JC:  You know generally any data set is going to have some error. What we do is calibrate one satellite against another or against two others if there are three up there at the same time. So we can tell which one might be off and that has actually helped us discover the types of drifts that occur in the satellite data. So we’re able to correct for those and we put our error range plus or minus 0.05 degrees C per decade. So over the last four decades that would be a change in temperature we know within two-tenths of a degree. And the change hasn’t been much in the last forty years.

CR: What is interesting is the trend I guess, not the actual measurement for each each day.

JC:  Yes, the change over time is what people are really concerned about. We can say the average temperature of the layer from zero to ten thousand feet is about 260 kelvin or about minus 13 Celsius.  But that doesn’t mean a lot to people. When you say, oh it changed by one degree from 40 years ago to today, people can relate to that.

CR: The policies about the climate especially in the western part of the world actually hang upon IPCC’s climate models. How well does do those fit to the observations that you use, that you do see every day?

From John Christy’s testimony 29 March 2017 at the House Committee on Science, Space and Technology. “IPCC Assessment Reports show that the IPCC climate models performed best versus observations when they did not include extra GHGs and this result can be demonstrated with a statistical model as well.”

JC:  The short answer is not very well. And we have tested many of these models through the years. We’ve really zeroed in on a part of the atmosphere that is very critical, that being the tropical atmosphere up around eight to ten kilometers or so. Because in that layer the earth releases a tremendous amount of heat. You can think of it like a vent that opens and releases heat and closes keeping the heat in. We found with climate models that they put a lot of water vapor and high clouds there that act to close the vent. When we look at the satellite data, it shows heat allowed to escape much more readily than models do. So the models keep the heat in, like closing that vent, and therefore the earth warms up faster than it should. When we compare the temperature of that layer with the actual measurements, the models tend to warm two to three times too rapidly. That’s a huge error.

CR: Is that by any means a scientific issue to be overcome, or do you see that the climate models they’re using have to be redone?

JC:  Right. We have published these results, other people have published the same results, showing that the climate models are warming way too rapidly in the tropical atmosphere. And so one thing to do would be for models to figure out how to keep the humidity, the water vapor up there, from getting so moist. Because that’s what the models are doing, making that level too moist which acts like a blanket or like closing the vent in other words.

If you remove that water vapor to some extent, it will allow the heat to escape to space. And here’s just one little calculation we did. In the real world when the earth temperature warms up one degree, you have about 2.6 watts of energy leaving. So the atmospheric temperature warms up one degree and the atmosphere sheds 2.6 watts. The same calculation from the climate models showed 1.4 watts. In other words, when the climate models warm up the atmosphere, they don’t release as much heat and so that heat is retained in the system and causes that extra warming that we see in the climate models.

And for policymaking as I mentioned earlier that just shouldn’t be the case because climate models should not be used for policy if they cannot model the system correctly.

Figure 8: Warming in the tropical troposphere according to the CMIP6 models. Trends 1979–2014 (except the rightmost model, which is to 2007), for 20°N–20°S, 300–200 hPa. Source: John Christy (2019)

CR: So in your mind why is it they are so wrong, what are they doing wrong? You mentioned they accentuated the water vapor, but what what is fundamentally wrong with the models?

JC:  Well I don’t know exactly how this works in the climate models.  When you require the humidity, the percentage of moisture to be constant, then if you warm up the atmosphere a little bit, you increase the amount of water vapor there to keep the humidity constant.  Warmer air holds a lot more water vapor than cold air, and so if you increase the temperature that means you have to increase the water vapor, which means you’re closing the vent and increasing the temperature even more.

To sum up in a very simple statement: The climate models don’t agree with what has happened in the past, and they don’t agree with each other about what’s going to happen in the future. So why would you use them for climate policy?

The policies are built upon this theory that when you raise co2 you you warm the climate a little bit atmosphere and then the water vapor will start to increase in the atmosphere and that will trap even more heat, and that’s gonna gonna make a warming spiral.

CR: Has that happened in the history of the earth?

JC: That’s a good point. If you look at the long history of the earth system, say for example when corals evolved about 60 million years ago or so. The earth had four times as much co2 as it does now. So in terms of life on the planet, co2 is food it’s wonderful for life. If we put more life, more co2 in the atmosphere the biological world would love it. In fact I was talking to some folks in the farming industry and they are creating fertilizers and so on to increase yield. They are able now to increase the yield of crops to the limit of what co2 is in the atmosphere. And they just can’t increase them any further because there needs to be more co2 for the plant to grow even better. Plants evolved at a much higher level of co2, so it’s no wonder why they are so happy when we increase it a little bit.

CR: So you you don’t see the current level of co2, the rising of the co2 wherever it comes from, as a problem climate wise?

JC: That’s right. I don’t see that the cost of rising co2 concentrations is that important. It’s certain that the plant world loves it. And you could also say there’s something else involved here. That rising co2 represents the fact people are living longer and better lives. And that’s a huge benefit that carbon energy has allowed people’s lifespans and the quality of their life to increase dramatically in the last hundred years.

At the same time because of our wealth, we’ve been able to mitigate the damages and the deaths from climate events you might have seen some of the charts that show deaths from climate events are down 95% in the past 100 years, because we are wealthier and use energy to protect ourselves from the climate.

CR: I guess one degree warmer climate will only benefit this growth because it’s easier to grow crops when it’s warm than when it’s cold.

JC: Yes, when you do a full accounting of the benefits of extra co2, you will find that you end up with a positive. If you put more co2 in the atmosphere that actually makes the living standards of people rise even more, and the biological world advance even more.

But is there a threshold so to speak. Let’s say as a guess co2 level have been rising about 100 parts per million over the last 100 years or so. It doesn’t seem that extreme. But could it in theory trigger some some kind of rapid warming if we release a huge amount of co2 by burning all the fossil fuels?  Could could it do some damage?

Well there are a lot of scary stories out there about reaching some kind of tipping point. But it turns out that the way carbon dioxide acts in terms of a radiative gas, the amount of energy it absorbs decreases in its incremental effect. So if you double co2 there is one effect; if you double it again that effect is less than half of what the first doubling was. So you have this approaching a limit when there is no additional climate impact from extra co2.

And these amounts of co2 will always be below any kind of threshold that would be cause it to be a pollution or problem. In fact if you can go into a lecture hall and take a co2 monitor, you will find it’s around a thousand parts per million. So a thousand parts per million is not a problem. for uh

CR: Do we know the the threshold for where where co2 doesn’t really do any anything more or is it still debatable?

JC: That is debatable because of how these feedbacks work that i mentioned earlier. Some people think that the feedbacks will always be positive as in adding extra water vapor making the temperature go up and up. That’s a positive feedback. We just don’t know enough about how those feedbacks will happen, but we can look at the past and see that they happen very gradually. And we see that the atmosphere has negative feedbacks too. The atmosphere has ways to shed that extra heat which keeps the planet from shooting off into some kind of runaway warming.

CR: I guess a lot of that water vapor will go into clouds and rain back that is cooling too.

JC: Yes, we have been trying to determine the sensitivity of the climate to co2 for decades.

CR: Are we are we close to finding a current answer?

JC: That is a very sore point among climate models as you probably know. Through the years the climate sensitivity from doubling co2 has ranged from: Will it warm up 1.5 degrees or 4.5 degrees Celsius. That’s been the kind of range, and the latest models show an even wider range going up to 5.6 so. The answer from the scientific community is: We don’t know what’s going on because every time we have a new model, we get a completely different result. And right now they vary over a factor of three, which is a huge error range for any kind of science. a factor of three

We have calculations with real data, with empirical data where we know how much extra forcing was put on the climate system. And then compare what the temperature response is over the past several decades. We get a number right at the bottom of that range about 1.5 to 1.7, which has very little impact in terms of climate events on the planet.

CR: So if co2 is not the dominant factor in a climate system, what is the dominant factor?

JC: Well, you have to talk about dominant factors on many time scales. On a year or two time scales we know that would be volcanic eruptions or el nino, la nina ocean circulations. As you go into century scale you have to talk about how the oceans change in their circulation, and is that going on right now.

Those things may be fooling us about what carbon dioxide might be doing. And that is the real crux of the issue. How can you know the impact of the extra carbon dioxide when mother nature is also playing big roles and causing changes. It’s very difficult to extract one from the other.

CR: I’ve seen a research recently with some physicists who who saw a link between the sun’s solar cycle and the la nina el nino. In their paper they used 22 year cycle of the sun and they actually see a link. Is that something you also find in your research or are you just focusing on the atmosphere?

JC: Well I’ve looked just at the last 40 years with our satellite data and for the stratosphere, way up in the atmosphere we see a very strong link between the solar variations and the temperature up there. But down in the troposphere it’s much harder to find just on a 40-year time scale. But on the longer time scales I have seen some results that show that the variation in the strength of the sunspot cycle, or really the solar irradiated flux that comes into the earth, does have a relationship with the land surface temperature. And so that’s another mother nature factor, those natural factors that confuse us when we try to figure out the carbon dioxide signal.

CR: There’s many factors in play all the time and they can make each other stronger, can make each other bigger.

JC: So we cannot forget the factor of internal variability. Apart from the sun or volcanoes, just within the climate system itself, there is the capability to organize itself and create hot periods and cold periods. If you look back in history you will see that just naturally the climate can have these large variations.

CR: Is that due to the ocean atmosphere connection or is it atmosphere layer who plays the role? Where does it come from?

JC: These kind of variations I believe are primarily driven by the ocean circulation and atmosphere response. But I have to say the atmosphere also has impact on the oceans so it is a two-way street
Why do so many indicators show that the earth was warmer a thousand years ago? Especially in many regions it was just warmer a thousand years ago than today, and yet the sun really hasn’t changed that much in that time period. So what other kind of natural variations would have occurred to create that warm period?

CR: You have been involved in the IPCC as a lead author a long time ago. Why did you leave that organization?

JC: Well the IPCC is not something you leave. The IPCC is something to which you are invited and I was invited to be a lead author because of the work on the satellite data and other temperature data sets I had built and published. That report that was the TAR or the third assessment report. IPCC has not allowed any skeptical scientists to be part of the authorship team since then. And so when they say we have the consensus of scientists, they have the consensus of the scientists they picked. So if you agree with the consensus then you get picked to be a author. And as you can imagine you end up with a document that agrees with this consensus.

CR: So have you been involved in any of the any of the conclusions?

JC: I have been a reviewer. I volunteered to be a reviewer but we found through the last couple of cycles that they really don’t pay attention to our reviewer comments if they are skeptical or challenge the views that IPCC wants to make.

I will say that there are some good things about the IPCC. If you go into the very thick document that outlines a lot of the individual results and research efforts, you will find some very good material there. It’s the summary statements that come out that the press feeds on. So the research details are pretty much ignored because they just want a dramatic story to tell.

CR: When I see the data that the global temperatures have risen from 1980 to around 2000 it seems to me there’s a kind of leveling off just like in the 1960s era. But co2 is still climbing as it it used to do. Has anyone come up with a explanation for this stagnation of temperature?

JC: The only explanation that really works is the the internal natural variability of the climate system. The system within itself can make warmer periods and colder periods happen. The el ninos and la ninas, those spikes every few years that last one or two years, pretty much balanced out in in the last 40 years. So that you have a trend overall of about 1.5 degrees per century. And that’s much lower than what the climate models have been indicating. They’re generally running about 2.5 to 3 degrees per century.

CR: There’s been a huge debate about whether this huge rise in co2 is due to human activity alone. What do you think about that?

JC: The humans have certainly caused most of it and they have some very good information about how that happens. One of the interesting ones is to look at the oxygen level in the atmosphere and the oxygen level has declined a very tiny bit that matches the increase in co2. When you burn carbon you oxidize it so carbon becomes co2 and you take that oxygen out of the atmosphere. So that’s one of the examples showing that the rise is almost certainly due to human progress.

I should say people don’t go out and burn carbon because they’re just bad people. We burn carbon because it helps our lives, it provides the energy that gives us longer and better lives. And more and more of the world wants to do that, in China and other countries.

CR: And we humans are kind of a tropical species we don’t thrive well in cold area, we don’t have energy and shelter so I guess we are smart animals

JC: Yes we have figured out that climate is dangerous. It’s always dangerous and we figured out how to make it safe. There’s a reason why not many people live in the arctic region and a lot of people live near the equator. So I tell the story that in the United States that over the last 120 years the temperature has changed about four degrees for the average American. Well that’s because a lot of Americans have moved to the south where it’s warmer. So the average American lives in a much warmer climate.

CR: Is is that due to poverty or something else or it just is easier to thrive in a warmer climate?

JC: I think it’s because warmer climates are just much easier to live with. You can go outside many more days a year and enjoy your outdoor activities because you’re a warm person now. Someone from Wisconsin in the United States says I love ice fishing and so they like the cold weather and that’s fine. and then they have a summer house in Texas.

CR: in your point of view what would be the most important to research within the next 5 to 10 years to have a better understanding of the climate system? What are the missing puzzles we need to solve?

JC: I think there’s always work to be done on the observational data sets especially especially a hundred years ago or so. But in terms of the science question, we need to know what happens in the in the upper atmosphere regarding the moist thermodynamics. How does water vapor change, how do clouds change? Those are the keys to understanding why in the real world when the earth warms up it releases a lot of heat but in the model world it doesn’t release that heat and retains it and keeps it hot on the surface.

CR: Is that something we are close to understanding or is it still a long time before we really have a big picture?

JC: That’s a very good question because this same mistake has been going on for 40 years and you would think that that modelers would really make a big effort to try to dial back to reduce that problem. But we just don’t see it.

CR: Is that because of the political influence in the science?

JC: You know that can’t be ruled out that. When you have a model that tells a terrifying story you get attention. And that helps you with future funding and efforts, and also helps you get published. Because publishers like to present scary things because that’s what people buy.

CR: I’ve spoken to a few scientists as you and they they all like see this trend that when you want to research something and if it could be a little bit skeptic towards the so-called consensus, it’s pretty hard to get funding. Do you think that this political control over science has threatened the public credibility of science?

JC: Yes I think that it has happened that climate science has been corrupted to a large extent. The funding agencies will fund those scientists who are looking at climate problems and and how bad the climate can get. They’re pretty much unwilling to fund skeptical type questions that people like me ask. We do have some funding, but if you look at the total picture, the amount of funding towards skeptics is well under five percent. So it’s a tough road to go up against that kind of money.

CR: I guess that’s why you don’t see that many skeptical articles being released, because they really don’t have the money to do the research.

Europe just made a big agreement to lower the carbon emissions to 70 % of of the current level
by 2035. In your point of view would that make any difference to the climate if the whole of Europe managed to do that? Would that change the temperature? Will we be able to measure the effect in terms of the climate?

JC: There won’t be any effect. I actually did the calculation if we completely eliminated the United States from the earth: no people, no car, s nothing. And the impact was very tiny, less than a tenth of a degree by 2050. So, no it’s not going to have an effect especially when the rest of the world wants to have the energy like we have. They want to have a life that’s long and that’s prosperous like we have. And so they will be using energy more and more and so Europe and the United States are not driving the bus on this.

CR:  So we’re pretty much out of the picture now. What what kind of actions does it take to tip the scale to make an impact? Because 100 parts per million seems a very tiny bit of increase. Would it matter if the whole world stopped to work?

JC: You know I can’t imagine that world but suppose in our imagination that carbon dioxide was just stopped. That wouldn’t have much effect on the climate because there’s so much co2 in the atmosphere already and so it wouldn’t change the curve very much. And the climate would not notice much at all.

Actually most of the policies they make in the U.S. and in Europe doesn’t have much effect on the climate system. If the climate models are right, and I don’t think they are, and we use these policies you’re talking about, the global temperature is going to be affected by hundreds of degrees not even a tenth of a degree because we’re still emitting. We’re only just taking down our emissions a little bit with great pain by the way. And you have to balance that with what kind of suffering are you causing. You know I lived in africa and i can tell you that without energy, life is brutal and short. Those people are people just like us and they want to have a lifestyle where they can live long and prosper. And we should not be the people to tell them they can’t. If in fact if you look at the real numbers they aren’t following any of our advice. They are moving forward with progress.

CR:  It seems this climate consensus, you know this worry about the climate is only the western world, U.S. maybe Australia maybe Japan, but it seems like the rest of Asia just really don’t care, they just go along and do what they’ve always been doing.

JC: The way i heard expressed one time is when you have food on the table you can worry about climate change. When you don’t have food on the table you never worry about climate change, you worry about putting food on the table.

CR:  Actually in in Europe especially in Denmark and in Germany we have have the highest energy prices in the world due to huge funding for renewable energy. And the number of energy poverty especially in Germany is rising like rocket because more more people cannot afford to to heat their homes. So it has a big effect on even modern society.

JC: You would think that policymakers would understand that that if you raise the price of energy you just raise the price of everything. And really what you’ve done is create millions of jobs in China and India. So you’re working toward a system of full employment for China and Southeast Asia and less employment in Europe.

CR:  If you had the power, if those policies shouldn’t be in effect, what would you change? if not that big priority in co2, what would you prioritize instead?

JC: Well you know I hadn’t thought about being a president of the world so that I could initiate policies. But I would roll back the regulations, especially those regulations that benefit the renewables. I would want them to stand on their own that they produce electricity at a price that people can afford. And let natural gas come more into play. And if renewables can’t compete with natural gas, then they should go away. It’s just a market economy, that’s a free market system where whatever is best and most competitive is that which survives. And that that’s what people want: to have the most affordable way to meet their demands.

So that’s probably the biggest thing. I would take a look at all those regulations that benefit renewables. When they have had benefits for decades and still cannot produce electricity at the amount and cost that we need.

CR:  There really isn’t in my point of view any alternative to fossil fuels, maybe nuclear energy, but eventually it will run out so we have to think about something in the future if not nuclear.

JC: Here’s what I would say about that. We didn’t leave the stone age because we ran out of rocks. And we didn’t leave the wood age because we ran out of trees. It’s because something better came along. We will leave the carbon age when something better comes along and I suppose it’s going to be something like nuclear because that has huge base load capability. It can produce lots of power and it’s very small in terms of its area that affects the planet. While these renewables require great amounts of area and they need the minerals that are used to build them. It’s a very environmentally damaging situation and then the waste that they create is huge and a big problem that we’re seeing now.

I think that we will be leaving the carbon age this century because we will find better ways to use nuclear. The way I see it there will be the types of reactors that can be deployed and built rapidly and provide just continuous power that we can use.


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