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Physicist Explains Where Climate Change Is Happening On Earth

Physicist Explains Where Climate Change Is Happening On Earth
Where is climate change currently happening on Earth, and what's causing those changes to occur? We speak to a physicist from the Jet Propulsion Laboratory about where major climate changes are taking place, and how climate modeling helps to predict future changes in our atmosphere.

Dr. Teixeira will be discussing the major climate changes that are taking place in the Earth's environment tonight at 5:30 at the Reuben H. Fleet Science Center in Balboa Park.

MAUREEN CAVANAUGH (Host): I'm Maureen Cavanaugh. You're listening to These Days on KPBS. Despite all the arguing and the political posturing that has gone on in this country about global warming, one essential element has usually been left out and that is, when it comes to the science of climate change most of us don’t know what we’re talking about. When we lack a common understanding about how the research is conducted and what it means then we end up choosing sides in a war of words rather than making good rational decisions about the future of our planet. This is a situation my guest, Dr. João Teixeira would like to see changed. He says we need better descriptions about what’s going on with our climate, better explanations, and models to demonstrate what scientists are learning about climate change and that’s because climate scientists are seeing these changes happening now and they are working diligently to predict what will happen next. I’d like to welcome my guest. Dr. João Teixeira is – he’s a climate physicist with the Jet Propulsion Laboratory in Pasadena and he will be giving a lecture tonight at the Reuben H. Fleet Science Center in Balboa Park. Good morning, Dr. Teixeira.

DR. JOÃO TEIXEIRA (Climate Physicist, Jet Propulsion Laboratory): Good morning. How are you?

CAVANAUGH: I’m great. Thank you for being here. We don’t normally associate the Jet Propulsion Laboratory with work on climate change so I’m wondering, what is the focus of your work?

DR. TEIXEIRA: So the Jet Propulsion Laboratory, JPL, has been for many years, although most of the time people hear about it because of Mars Rovers and other missions to the planets, JPL has a huge and consistent effort in observing the climate system. So many or more than half of the NASA instruments right now that, you know, go around the planet in satellites observing the atmosphere from temperatures to the Arctic sea ice to snow cover, come from JPL, have been developed at JPL, and are right now being analyzed at JPL. So there’s a long interest at JPL in earth and climate sciences.

CAVANAUGH: Well, I’m sorry, I didn’t mean to interrupt you but…

DR. TEIXEIRA: No, sure.

CAVANAUGH: …therefore, if all these – if all this equipment is being trained on the climate basically…


CAVANAUGH: …to try to model it and so forth, what are we learning? What are the climate changes currently taking place on earth?

DR. TEIXEIRA: So we’re learning a lot. And actually, there’s a couple of messages I’ll try to convey this evening. One of them is that climate change is actually going on right now, that’s it’s not something that, you know, may happen in 50 years and we should start kind of being worried about it or something. It’s really going on. And it may not be Katrina or we don’t know if it is Katrina but there are, you know, systematic changes and one of the ones I highlight during the presentation is the reduction, the significant reduction of the Arctic sea ice cover. We have been able to measure the cover of the Arctic sea ice so how much of the Arctic is covered by ice? And we’ve noticed since 1979, when the observation started, that there’s been a significant reduction of, you know, something around 40% and that in 1979 the amount of sea ice during summer, because there’s a decrease during summer, was about double of what it was in the summer of 2007. So this is something you can actually observe. I mean, you can look at it. You – there’s plots and you can look at the plots and it’s something that the public can actually, you know, empathize in a way because just saying that the global mean surface temperature is increasing by, you know, 0.1 degree every ten years, it doesn’t really touch you personally. I mean, there’s nothing really that – unless you realize what the consequences could be, it’s very difficult because, you know, 0.1 changes in temperature are not something that you feel in any sort of dramatic way. But things like the Arctic sea ice, or the decrease of ice in Greenland, those are things that we have been measuring by satellite and are clearly there and are significant.

CAVANAUGH: And I think a lot of people have seen pictures, video, of the melting of the – Greenland’s ice pack, you know, that…

DR. TEIXEIRA: Right, right.

CAVANAUGH: …and I wonder, is – Would you say that that is the most dramatic climate change going on now? The melting of this ice?

DR. TEIXEIRA: So there you have to distinguish two things. One is the Arctic sea ice that covers the ocean, and then there’s the Greenland ice, and they’re both very dramatic. The one that you actually – the one that is most dramatic right now, that you can actually see with your own eyes if you look at these plots on the web that come from the satellites, is the Arctic sea ice because it has been reduced by almost 50%. That’s something that’s quite dramatic. But the disappearance of the ice in regions like Greenland is the one that may well have the biggest and the largest impact because that’s what’s going to change the sea level height, and that’s the one we understand the least because there’s a lot of dynamics of the ice over land that we really do not understand let alone model. So if one is more significant right now, the other one is the one that probably we should be the most worried about for the next 20 or 30 years.

CAVANAUGH: I see. I see. And do you know where people can actually see those pictures of the, you know, the surface ice melting?

DR. TEIXEIRA: Oh, yeah, I mean, the easiest thing is, of course, always to go to Google and put, you know, ‘arctic sea ice reduction’ or something like that and you’ll be, you know, there’ll be links to the different national laboratories that actually have been doing climatologies of the sea ice and the Greenland ice for a long time. So there’s nothing easier than going to Google and you’ll find something.

CAVANAUGH: Oh, thank you. Well, with the changes to the global surface temperature and the ice melting, are – the global surface temperature seems harder to understand.


CAVANAUGH: Why are – How can we begin to model that kind of information so that people who are not climate scientists…

DR. TEIXEIRA: Right, right.

CAVANAUGH: …can begin to understand that?

DR. TEIXEIRA: It is difficult. So the important point is really to realize that there are other changes that are much closer to us and are much easier to understand in a sort of intuitive way and we should focus on those ones because they are all related to this increase of a global mean surface temperature. But I can use a medical analogy and I think medical analogies are very useful here and not used enough. If you have fever, you know you have fever but you have no idea what it is, right? Do I have the flu? Do I have something else, right? So you can think of the global mean surface temperature increase as the fever in a way. But then that will manifest itself, what could be the, you know, manifest itself in a variety of other symptoms, not that those symptoms cause the global mean surface temperature increase but sometimes they do and there’s a feedback but that’s a slightly different story. So I would argue that the best thing is for the general public to focus on what is actually going on to make up your mind and see that this is really going on and try to learn a little bit about it. And I think we, as climate scientists, should probably try to do a much better job in trying to convey what the consequences are of this increase of global mean surface temperature without getting into any sort of bandwagon of – any sort of agenda that, you know, this terrible catastrophe that are going to happen because of this or that. I mean, we should be, you know, level headed and unbiased and explain, this is what is going on and this is what we predict and this is the probability that this may happen and these are the models that we have and explain how good or how bad they are.

CAVANAUGH: I’m speaking with Dr. João Teixeira. He’s a climate scien – physicist, that is, with the Jet Propulsion Laboratory in Pasadena. And I want to talk to you a little bit more about the idea of doing a better job explaining to the public. How could scientists go about doing that?

DR. TEIXEIRA: Well, I think scientists have been trying. There are a couple of problems here. One is that the discussion, I have a feeling, tends to be between the two extremes. So the discussion that the public is usually allowed to see or that often is on the media tends to often be between, you know, the two extreme sides. And, of course, it’s always a big complicated problem because those two extreme sides may have their own agendas that are my – and their opinions are all not unbiased. They are biased opinions. So how can a climate scientist that has no agenda be able to come in and – in the debate and say, look, this is what’s actually going on. Now, my feeling is that people are doing a lot of great, you know, public science and popular science, and you can go to the Discovery Channel or you can buy books and there’s a variety of information out there. But I – My main concern is that the amount of people, the amount of scientists, the number of scientists that are actually working on the physics of these climate models and on the physics of these observations, of these climate observations, the number is relatively small. It’s actually quite surprising when I mention this to people. The number of people that actually use data facts from these climate models, for example, is enormous compared to the number of people that actually understand what these models are about. So most people don’t even have the time, most scientists don’t even have the time to, you know, to do their own job because there’s only 24 hours a day and the problem is so enormous let alone, you know, being out there and explaining to the people what is going on so that there – you know, there’s a lack there that I’m not sure exactly how can it be filled but it needs to be.

CAVANAUGH: How far, with the modeling you do now on the climate, can you – How far into the future can you accurately predict? Do you have any statistics on that?

DR. TEIXEIRA: So, one of the things I’ll try to convey this evening is that the model that we use to do climate prediction are virtually the same as we use to do weather prediction. And when we do weather prediction, you know, 40 years ago people didn’t really trust weather prediction at all and, you know, rightly so. But today someone tells you it’s going to rain in San Diego or in LA in three days time, people know that, you know, it probably is going to rain in LA and San Diego in three days time. It may not tell you exactly what the precise hour is in which the rain is going to start, it’s not going to tell you precisely how much rain is going to fall. We try to do it but it’s not accurate enough. But it is accurate enough to say that, you know, it’s going to rain in LA in three days time, and people know that. The question you asked is the important question, which is, is there an analog of this for climate? Can you actually say with confidence that in 100 years time the global mean surface temperature is going to be, you know, 4 degrees warmer and, as such, the summer Arctic sea ice is going to be disappearing and that the Greenland ice is going to disappear by 10%, and can we do those statements with the same confidence that we do the other one, saying it’s going to rain in LA in three days time. And the answer is no. Right now, we cannot tell you exactly what’s going to happen in 50 years time, in 100 years time, and the problem is extremely difficult. It’s very probable, it’s almost certain that the global mean surface temperature’s going to increase by something between two degrees Celsius and four or five degrees Celsius. But apart from that, it’s extremely difficult to go beyond and say there’s going to be – you know, California is going to be, you know, dry, or California’s going to be wetter. I mean, those types of predictions are extremely uncertain. So we need to improve our models and we need to develop the statistics you’re talking about to be able to inform the decision makers in this country and in the world about, you know, what is exactly going to happen or what is the probability that something like a severe drought in California is going to happen in the next 50 years.

CAVANAUGH: I know one of your main messages is improving the accuracy of climate models and tell us a little bit more about what value the public would gain from having climate models that can accurately predict what’s going to come up maybe 50 to 100 years from now.

DR. TEIXEIRA: There will be tremendous – Imagine now that the U.S. government, as all the other governments are going to Copenhagen in December to debate what sort of international treaties need to be done to tackle this problem. Imagine now that they would go there and they would know with, you know, relatively good accuracy what’s going to happen and what can the models tell you. And we know, well, the models will tell you that this is going to happen and this is going to happen, and we are pretty confident that this is going to be the case. That’s good, that would be a tremendous argument, right? Who would be able to argue with that? But we can’t right now, I mean, and this ends up being the problem. The problem is that a lot of people are unconvinced because they do not trust the climate model. Now, often they do not trust the climate models because I think they tend to be biased or often they don’t completely understand necessarily what the climate model is but part of their concern is correct. We do have a tough time predicting accurately what’s going to happen in the next 100 years because the climate system is extremely complex.

CAVANAUGH: Do you have an idea what is needed to make those climate models more accurate?

DR. TEIXEIRA: Well, a lot of us do have ideas of how to make it accurate or more accurate. What we need is investment, not only investment in terms of funding—that’s always necessary—but there needs to be investment in a variety of other aspects. Again, the number of people that work in these models is so small compared to what should be. And, you know, it goes beyond the funding for the next five years. It has to do with education, you know, getting the right people, doing the right things, studying the right things, and it could well be that at some stage the problem will be so overwhelming and the people will realize that, that they will try to put together major efforts in trying to improve these climate models. Many people have been trying to argue for that but as far as I know and as far as right now, those arguments have not been, you know, convincing enough. But I think an important point is to use this – to use the medical analogy again, when you feel unwell and you go to the doctor and the doctor says, well, I’m really sorry, I’ve rerun the diagnostics and you really need surgery because if you don’t have surgery, you know, so-and-so is going to happen, you may, you know, you may consult another doctor, get a second opinion, but if the second doctor comes and says more or less the same thing, most people would, you know, rely on the doctor, trust the doctor, and do the surgery and, you know, rightly so. But the interesting thing is that we know much less about the human body than we know about the climate system. The climate system, we know more or less what the equations are, we know what we need to do. It’s a complex system but we know much more than the human body. However, we rely on our doctors much more than we end up relying on the climate scientists. And the reason is, of course, that what’s on the side of the medical scientists is the fact that there are so many people getting sick, right? So you can develop statistics and you know that if you have so-and-so, these symptoms, then, you know, statistically, on average, you will develop the following disease and the following consequences will come about. Unfortunately, we only have one earth, we only have one climate, right? So the point here is that although we know much more, we haven’t been able to, you know, have a consistent effort both nationally and internationally in trying to use all the knowledge we have and the best people we have to actually improve these models and be able to in, you know, in 10 or 5 – 5 or 10 years be able to say something much more concrete about what may happen.

CAVANAUGH: I know that your focus is to try to keep as close to the actual science as possible and not get carried away with theories. But I’m wondering, as a scientist who studies the climate, do you have a feeling whether – about the global warming problem, what can be done about it or maybe if it’s too late to stop it at this point?

DR. TEIXEIRA: That’s, you know, understanding the climate is a daunting task. Trying to solve the problem is a much more complicated task, right? And I don’t think anyone really knows what the solution is. I’m an expert in the physics of climate. I have my own opinions, of course, and I think probably the most important thing right now is to realize that climate is changing right now and that something needs to be done about it but it’s going to be extremely complicated to do it. If it’s going to be – Whatever we’re going to do in the next 10 or 20 years probably is going to be crucial to whatever’s going to happen but it’s going to be so complicated. Imagine that most of the pollution problems that we’ve been affected by is local problems, right? So you have a factory or a plant in a particular town and, you know, they’re polluting the water so the local authorities and the national authorities come in and they rule and the EPA comes up with some sort of regulation and we shut down the factory but it’s a local problem in general. Now the CO2 or the greenhouse gases problem and the global warming is a global problem. Whatever we’re doing here and whatever we’ve been doing for the last 100 years is affecting everybody and it’s going to affect everybody in the world for the next, you know, hundreds of years. It’s not a problem that is going to stop in the next 100 years. It probably is going to affect us for a very long time. How do you – how you get agreements between the different nations to actually be able to tackle a problem that is completely global in nature is going to be an enormous, I mean, a gigantic task. I’m not necessarily optimistic or pessimistic, I just need to say that from my scientist point of view, I find that an absolutely daunting task.

CAVANAUGH: Now, as I mentioned, you are lecturing tonight at the Reuben H. Fleet Science Center. I wonder what it is you hope people will do with the information that you give them tonight.

DR. TEIXEIRA: I hope people go back and Google things and try to find out more about it and realize that – Forget about the two extreme positions, don’t worry too much about the politics in this, just try to see what the facts are and try to understand what the science is. And if you think about other things that are controversial like evolution is controversial in this country or, for some people, the big bang is controversial, well, global warming is – the facts are much more obvious, much more clear and it should be naturally much less controversial. The only reason it is controversial is because there are political agendas in the two sides of the spectrum in a way and those confuse people And that’s what people should try to do, try to be unbiased, not confused and get the facts and, you know, make up your mind.

CAVANAUGH: I want to thank you so much for speaking with us this morning. Thank you.

DR. TEIXEIRA: Thank you very much.

CAVANAUGH: My guest is – has been Dr. João Teixheira. He is a climate physicist with the Jet Propulsion Laboratory in Pasadena. He’ll be discussing the major climate changes that are taking place in the earth’s environment. That’s tonight at 5:30 at the Reuben H. Fleet Science Center in Balboa Park. And you’ve been listening to These Days. If you’d like to comment on anything that you hear on These Days, please go to And stay tuned for hour two coming up on KPBS.