Can one climate change scientist change the minds of a roomful of climate change sceptics?
Airdate: 
Tuesday, September 7, 2010 - 20:30
Channel: 
SBS One
An Insight special.


 
In late June Insight recorded this program with internationally renowned climate change scientist Stephen Schneider.
 
A few weeks after we recorded this program, Stephen Schneider died on a flight from Stockholm to London. He was 65 and had been battling a serious illness.
 
Stephen Schneider was a passionate believer that science should engage directly with the public on the issue of climate change.
 
It was in this spirit that he appeared on INSIGHT.
 
He faced a crowd of 52 climate sceptics and they were asking the questions.
 
Watch the debate and find out if anyone changed their mind.

Transcript

JENNY BROCKIE: Man made climate change was once a major public concern but political momentum to address it has waned and the public has become more sceptical. Tonight, an audience of doubters meet one of the world's leading climatologists who will try to win them over. Professor Stephen Schneider is from Stanford University and is a lead author with the IPCC, the Intergovernmental Panel on Climate Change. Stephen Schneider, thanks very much for joining us here and thank you to our audience too for joining us here at the University of NSW, good to have you all. Now I want to give you a flavour, Stephen Schneider, of what you are up against. So I am going to go to our audience first. Tania, do you believe in man made climate change?

TANIA BERMAN: Man made, not at all, not at all.

JENNY BROCKIE: Why?

TANIA BERMAN: No"‘one has proven to me that it's man made at all. All I see is a big hysteria just for money. The only reason you're getting grant money is because climate change, the planet is warming, it's the only reason you're getting grant money. If we didn't have this hysteria there would be no grants, there would be no money "‘ no people making money at all.

JENNY BROCKIE: Okay, going to take a few comments and then I will come to you. Peter Laux, what about you?

PETER LAUX, TRAIN DRIVER: Um, no I don't believe in it at all. I believe in climate change, the climate always changes but I haven't seen any evidence to date that discounts natural climate change and I've seen nothing in any of the literature that I've read indicates that anything is abnormal A, with the warning or the rate of warming.

JENNY BROCKIE: Mark you are nodding your head.

MARK YACOUB, BUILDER: Well, I believe nature has its ways of balancing itself and if you went into an extreme global warming I'm sure it's got its own methods of cooling itself.

JENNY BROCKIE: And Peter, your son, what about you, how old are you, Peter?

PETER YACOUB: I'm 15.

JENNY BROCKIE: And what do you think?

PETER YACOUB: Um, I'm not too much of a sceptic but I do believe that, um, climate change is, um, something that's happening naturally in, um, in our world but I do think that it can be implemented by mankind as in that what mankind is doing is just accelerating it so I don't believe global warming is man made, I believe it's natural and that it does fall in to our climatical pattern.

JENNY BROCKIE: Alright, Stephen Schneider, plenty for you to deal with there. You have been looking into these issues for 40 years. What is the most compelling argument that you can throw back at these people, and they are all doubters, to make the case for man made climate change.

PROFESSOR STEPHEN SCHNEIDER, STANFORD UNIVERSITY, USA: I heard the word "I don't believe". Science is not about belief, science is about evidence and therefore your beliefs have to be built upon looking at the whole wide range of evidence and it is completely legitimate, as everybody said, to look over a long period of history. In fact looking back at the geological past that's the backdrop against which we calibrate our understanding but you have to be very careful not to make an analogy by saying that what happened in the past is caused by the same things that are happening now.

So the point is what we do in science is we look for underlying cause, not for the fact that before it's been warmer. In fact it's been quite a bit warmer than now before, 125,000 years ago it was degree and a half warmer than now. But we know that the Earth's orbit was twisted more towards the sun than now and if we take that and we put it in the same climate models we use to study global warming it predicts it was about that much warmer. So what we try to do is look at the wide range of evidence and that we don't use analogies, what we do is we use the understanding built on how the system works and I'll be happy to explain that more.

JENNY BROCKIE: Janet, you wanted to say something.

JANET THOMPSON, CATTLE FARMER: I think it's very good that Professor Schneider has started out by saying we need to look at the evidence. I don't think anybody in this room disagrees with that. The hypothesis that we are currently faced with is that carbon dioxide is the driver of climate change and throughout history we have proven evidence that temperature has been much colder with higher degrees of CO2 in the atmosphere than what we have today and vice versa. Can you "‘

JENNY BROCKIE: Can I just ask you, Janet, do you believe that the Earth is actually heating up at the moment. Do you believe that the warming is occurring regardless of the cause?

JANET THOMPSON: Well, I don't believe anything, I look at the evidence and the evidence says that we did have warming, yes, we have been in a long"‘term warming trend the last 15 years, we haven't had no statistical warming and so I think that's a problem with this hypothesis. I believe that the hypothesis has been shown to be false.

PROFESSOR STEPHEN SCHNEIDER: Yeah, okay, that's wrong, sorry - that's not what the evidence says. First of all there's plenty of statistical warming over the last 15 years. The argument is whether it was "statistically significant" which is a particular kind of statistical test that's very stringent. In fact the last, what are we now, the last "‘ first half of 2010 is the warmest year ever recorded in the thermometer records and that what happened is from 1992 to about 2002 it went up so fast you could have said we were going to hell in a hand basket. Then from about '98 on to about 2009 it was relatively flat. This is what climatologists call noise. That means that the decade"‘to"‘decade fluctuation in the climate is about the same size to slightly smaller "‘ to slightly larger, excuse me, than long"‘term multi - decadal trend you would expect from human activities. So to point to any one decade like the decade of the 2000s and say well that hasn't changed very much therefore this disproves global warming would be as ridiculous as the deep environmental groups, and some of them did it, pointing to the decade of from the 1990 to 2000 and say oh my god, it was terrible.

The thing about global warming is that it's global and long term. No climatologist defines climate change on the basis of a decade. It's usually defined on the basis of multiple decades and on that multiple decades since about 1850 what IPCC said is correct, it's unequivocally warming but that's not a very strong, strong statement because how much is that due to Mother Earth and how much of that is due to us. That's a tougher question which I will be happy, in fact must address which many of us brought that up in your opening comments.

JENNY BROCKIE: We'll get on to that in a moment. Does that answer your question, Janet?

JANET THOMPSON: Well I've heard that explanation before. I think we've got a fundamental problem in that we are wanting to change our entire economic structure based on the hypothesis that CO2 is the driver of climate.

PROFESSOR STEPHEN SCHNEIDER: That's a different question. That's what we call detection attribution. I promise you I'll talk about that. Right now we're only talking about is the climate changing? I would argue the answer to that is it's unequivocal that it's changing, that is not the same thing as saying why. That's a much more sophisticated and tough problem.

JENNY BROCKIE: Okay, Chris, I know you have a question about climate records, you're worried about the records?

CHRIS MACDONALD, PUBLIC SERVANT: And it kind of goes to what was being said just a moment ago about extrapolating over too short a period and with respect 160 years in geological time is a hell of a short period to extrapolate anything over. What concerns me is this focus on what you call the thermometer record I think was the term you used. There are historical records, albeit not written down in nice scientific tables, which run a much longer period and show big changes in the climate. Once upon a time you could grow wine grapes in England then suddenly you couldn't and then about 20 years ago you could again. So when you talk about the climate changing over this short period what worries me, and with respect I don't know what you have to say, but many of the people who do talk about climate change ignore all of these other records, everything before 1850.

JENNY BROCKIE: Okay, I'll get a response from you to that in a moment but this is kind of tied in as well. I want to show what geologist Ian Plimer has to say about warming and warming not being all that bad according to him.

PROFESSOR STEPHEN SCHNEIDER: That's two issues we'll take both of them.

IAN PLIMER: In Roman times we had 600 years of warm climate, sea level didn't rise but it was warm and we know that because they kept good records about agriculture and it was warmer, probably five degrees warmer than now, then it suddenly got cool. Now those prosperous Roman times were wonderful. When it got cool we had famine. We had a break down of the social structure, we had depopulation and the weakened population got hit by the plague. That's what global cooling did. And then it warmed again. The first to feel it were the Vikings and they grew barley, wheat and had cattle and sheep on Greenland. Why do you think it was called Greenland? Eric the Red was saying come to Greenland, wonderful benign climate. He was running a great immigration program. It was warm.

JENNY BROCKIE: Okay, Stephen, response to that first.

PROFESSOR STEPHEN SCHNEIDER: A couple of things. First of all Eric the Red was a land swindler. Iceland which is called Iceland was much warmer than Greenland and it was a way to get people to go there. Yes, it was a little bit warmer in Greenland but you cannot judge global climate on the basis of what happens in Rome or on the basis of what happens in Greenland. You have to take a look at the entire globe and one of the things that was clear is that the North Atlantic sector, right, Europe and Greenland and those areas, they have a much larger excursion of temperature in the short run than does the whole hemisphere and that's now been studied quite carefully by looking at tree rings which give you the width of the rings tell you something about what's going on, they're not a perfect measure. That's not the only thing you do, you look at pollen.

There are groups which have spent a lot of time - people have made assertions that the climate scientists are not looking over the last 5 to 10,000 years, I'm sorry to say that's not true. Please read the Intergovernmental Panel on Climate Change report and there's an entire chapter of what we call paleo-climate and it in fact takes a look over that record and if you take a look at the reconstruction of the last 1,000 years, and it's controversial how to do it, because a tree ring is not measuring "‘ it's not a thermometer but it's proportional to temperature.

So what you have to do is calibrate it, meaning taking a look at the width of those rings while they overlap with the actual thermometers which are much more accurate measures. Once you do that calibration now you run it back 1,000 or 2,000 years and when you do that you find that the last 40 to 50 years are warmer than any calibration anyone has done on the hemisphere "‘ on a hemispheric basis, not Greenland, not northern England, not what we called cherry-picked locations which could be warmer or cooler but the whole hemisphere and that's how the scientific community does it.

JENNY BROCKIE: Ian, you've got a question as to whether the temperature is rising because of global warming.

DR IAN RIVLIN, DOCTOR: I understand that carbon dioxide that man produces is 3% of what nature produces. How can small changes to our production of CO2 impact upon something as large as the Earth? It seems absurd.

PROFESSOR STEPHEN SCHNEIDER: Yeah, no, it's not only not absurd it's absolutely true but it's a very good question because what happens is that nature has long been taking carbon dioxide from the air, putting it into green plants and then of course this is what happens in the spring time when the sun comes out stronger and photosynthesis goes faster than respiration, that's decay when the CO2 goes out. Then in winter time when the sun goes away, goes to the other hemisphere, gets cold and the leaves fall and then they decompose. So there's a large natural seasonal cycle which in any one year is larger than human injection.

But that cycle's balanced meaning that the amount of CO2 that comes out of the air into the trees or into the oceans are much larger in any one year than what humans inject, almost exactly the same amount comes back up. So what we are is we're a net on top of that. So it's like saying that, you know, in your family budget you have large income and you have large expenses, but if now all of a sudden and let's say it's $100 and $100, now all of a sudden if you add $3 of income it's still going to accumulate in your savings even though the income was $100 and the expense was $100 so what happens is"‘

DR IAN RIVLIN: Sorry to butt in on this. Look, you're not answering the question. I said that we produce approximately 3% of natural production, you haven't really addressed that. You've given some prevaricative answer.

PROFESSOR STEPHEN SCHNEIDER: Perhaps what you haven't understood the answer. What I said is the amount of carbon dioxide coming from the atmosphere "‘

DR IAN RIVLIN: No, I understood the answer perfectly. You "‘

PROFESSOR STEPHEN SCHNEIDER: "‘ goes in and out and it's larger than what we inject but it's a balance.

DR IAN RIVLIN: If we produce 3% carbon dioxide of the total production of carbon dioxide it's still a small percentage. If we reduce our carbon dioxide by 50% and send ourselves back to the Stone Age we've made very little difference. Could you answer that question? I did understand what you said perfectly.

PROFESSOR STEPHEN SCHNEIDER: Well then I don't understand how you could reach that conclusion. Are you trying to say that we could not have a build up of carbon dioxide over the past century because of the human injection?

DR IAN RIVLIN: Absolutely I am.

PROFESSOR STEPHEN SCHNEIDER: Then you're totally wrong.

DR IAN RIVLIN: I'm saying there's homeostasis in the Earth that small extra production of carbon dioxide would easily be absorbed into.

PROFESSOR STEPHEN SCHNEIDER: I think you need to study this problem.

DR IAN RIVLIN: I've studied it "‘

PROFESSOR STEPHEN SCHNEIDER: Obviously not well. Let me give you an example.

JENNY BROCKIE: Okay, one at a time. Let Stephen respond.

PROFESSOR STEPHEN SCHNEIDER: If you have a bath tub and you turn it on so you're getting in a gallon coming in a minute right, and now the drain has opened up to a point where a gallon is going out in a minute. So there's a flow in and there's a flow out. That's an analogy to the fact that that there is a very large flow of carbon dioxide naturally going into the system in the summer time and coming out in the winter. Much larger than the 3%, I agree with that. However, it's in balance. The amounts are the same. So when you add the 3% it's 3% this year and next year and next year and next year.

JENNY BROCKIE: So it's cumulative.

PROFESSOR STEPHEN SCHNEIDER: And it accumulates. So if all of a sudden I go to the bath tub and I make the gallon into 1.2 gallons and don't change the drain size in the bottom the water in the bath tub is going to rise. That is completely well established, it's been established for a long time and if you don't accept that you really need to study science. You're just wrong.

JENNY BROCKIE: Jon, you wanted to say something?

JON WOODLANDS, NURSERYMAN: One of my concerns is the actual position of many temperature recording stations. Apparently last year there was a survey in America, they looked at about two thirds of the all gauges, I think it was 807 they assessed and 89% were considered too close to artificial heat sources such as buildings and where they actually separated them and looked at the well"‘placed temperature gauges there seemed to be a bit of a decline over the last 10 years. So "‘

JENNY BROCKIE: So you're questioning the accuracy of measurements.

JON WOODLANDS: Yeah, I think it's a factor

PROFESSOR STEPHEN SCHNEIDER: Yeah, a good question and so do the scientific community. Often there's an interesting tension between the people who model and do theory and the ones who measure, the latter group tends to be a bit more sceptical. Let me just interrupt myself for a second. I am actually very pleased that you're sceptics. There's no such thing as a good scientist who is not a sceptic, now on to the instruments, it is absolutely true that there are problems with instruments and the community spends a great deal of time on it. So how do they account for what you call "‘ what you were talking about which is cities accumulate heat. They do that for two reasons. One is release a lot of energy and that directly warms it up in a location and the second is we cut down the trees and the grass and therefore we get rid of the cooling effect of the evaporate transpiration and it has the name - it's called the urban heat island effect. If you ever listen to a weather forecaster, you can hear it right here in Sydney, it's a little cooler in the suburbs than it is down town. New York is the ultimate example where in the winter time it can be 5 degrees cooler in the suburbs - large amounts than it is in the city.

However, what the climate scientists have done over the years, I don't do this kind of work but I have many colleagues, is they go and they take all the thermometers, it is certainly not 80% of thermometers near cities, the vast bulk of them are distributed and are not, you know, affected by urban heat islands, and they pull them out of the record and it takes this record which is about eight tenths of a degree warming and it drops it down less than a tenth of a degree. Then they do something else, they look over the last 50 years at the population growth of cities and then they correlate temperature to population growth because the more people are there, they're using more machines and they're clearing more land and adding more pavement - turns out it's a very good correlation.

So if you use that as a correction and you take the population of these cities and you subtract warming according to that you get almost again the same answer. So that very good question that you asked is exactly the same question that climate scientists have been asking themselves for 30 to 40 years and their answer is it makes very, very little difference and it's corrected for and you have to correct for it or you wouldn't be doing it right.

JENNY BROCKIE: I want to get back, I want to get back to whether this is human induced, whether CO2 is causing global warming. Now I just wonder from what you've heard so far, Tania, are you any more convinced that CO2 is the cause of global warming?

TANIA BERMAN: Not "‘ I think CO2 is actually beneficial for us. It's heating up the Earth, it's producing vegetation, it's producing food, I don't see what all the drama is. It's only going up a slight amount and yet we're going to change our whole economy over this slight amount that's actually helping us. It's beneficial.

PROFESSOR STEPHEN SCHNEIDER: If you're a green plant and you live by yourself CO2 will make you grow faster, there's no doubt of that. However, if you're a green plant that's not very, very helped by CO2, only a little bit, and there's a bigger one that's helped a lot, it's going to get a very bigger leaf, shade you out and you're worse off. So what CO2 does is it changes the competitive balance of plants in an ecosystem therefore it's hard to use a word like good or bad. If you have a corn field I'd argue it's probably good in the sense that it's going to be increasing your crop yields because the corn field's an artificial ecosystem that you've turned into a monoculture. In a natural system it's not very good because it's changing things in a way that we don't know how to do it.

With CO2, I'm not talking about climate change. Even if there was no climate change, where CO2 is very threatening is that CO2 if this were a soda, right, we'd know that it would be carbonic acid, that it would be acidic. Well the ocean is slightly anti"‘acidic and it has now come down a tenth of a pH point, what is that, 10, 20%, I forgot the number, more acidic than it was. That's because we're turning it more towards soda pop. As we start adding CO2 to the atmosphere you make the ocean /PH"‘RS acidic which affects the food chain at the bottom. It affects calcium carbonate shells.

JANET THOMPSON: But the terminology you are using is alarmist. The ocean is not acidic, it is alkaline and what you're talking about is going from a pH of about 8.2 down to 8.1. So we have a lot of scaremongering going on throughout the world. Earlier you said something about a 30% increase in CO2, the impact of CO2 on temperature is logarithmic - it is not linear, so that 30% doesn't really mean a lot when we've already had a doubling of CO2 back in the early part of the temperature records. So I'm concerned about the general amount of alarmism that is out there and the terminology that is being used.

PROFESSOR STEPHEN SCHNEIDER: Can I just quickly answer that? I'm concerned that you’re kind of repeating a mantra from what you've heard from discredited information.

JANET THOMPSON: What discredited information?

PROFESSOR STEPHEN SCHNEIDER: CO2 is certainly a logarithmic absorption.

JENNY BROCKIE: For the person at home what does that mean?

PROFESSOR STEPHEN SCHNEIDER: I'll explain that. If you add an increment like that you trap say one watt per square metre. You now add an equal increment on top of that you trap 0.9 watts per square metre. It decreases.

JANET THOMPSON: In common terms.

PROFESSOR STEPHEN SCHNEIDER: Can I please finish? This is something which for 50 years we have known. This particular calculation with a logarithm has been in every climate model that any competent scientist has done is already discounted for and when people try to say that because CO2 is logarithmic absorber and therefore it makes no difference they either do not understand climate science or they polemicising because it is an absolutely every single model. It has long been accounted for and it is completely understood.

JENNY BROCKIE: Raq, you're nodding, you're supposed to be a sceptic, you're agreeing with this?

RAQUBUL HASSAN, SUSTAINABILITY OFFICER: I sit elsewhere, actually. I act as if someone who believes in the anthropogenical link to climate change, however if you ask me about the climate science, do I believe it is absolutely certain and I refer to the IPCC how there's inbuilt uncertainties in the model, I can't be 100% sure that it's going to happen but at the same time I'm not sceptical either.

JENNY BROCKIE: Insight is coming to you from the University of NSW with an audience of climate sceptics and one international scientist, Stephen Schneider, who is trying to win them over. Okay, Case, you had your hand up earlier before the break and I know that you're questioning the link between CO2 and global warming.

CASE SMIT, RETIRED CHEMIST: I certainly am. The first one is we've just come back from Alaska where Glacier Bay in 1750 was a total glacier. By 1860, that's 110 years later, half of it had melted. Now the IPCC gives examples of melting of glaciers as a proof that global warming is having an affect on glaciers. Now, this glacier melted long before any anthropogenic CO2 could have had an effect. Furthermore the glaciers that originate at low altitudes in Alaska are receding, the ones that originate at high altitudes are actually advancing in spite of the fact that Dr Schneider has said that higher altitudes warm up faster. So I'm asking the question, how do you explain that contradiction.

PROFESSOR STEPHEN SCHNEIDER: Okay, maybe my American English was a problem. I should have said higher latitudes, if I said altitudes I misspoke. First of all with regard to the fact that there's been glacier melt earlier, yes there has. What IPCC has done is it's counted the numbers of glaciers and the rates of melt and argued that that's accelerated substantially in the 20th century relative to earlier. It's not true to say that humans didn't do anything before 1750 because there was a lot of agriculture and land clearing and something between 20 and 40% of the CO2 accumulated, you know, in the human civilisation era is from land use so. Some of it is obviously related to that. So I wouldn't rule it out but it would be much, much smaller, I agree with you, than now.

With regard to glaciers getting built up at a high altitudes, that is in fact exactly what the models predict because if you are below freezing, well below freezing, say 10 degrees below freezing and now you warm up to 5 degrees below freezing, we all know that the atmosphere holds more moisture when it's warmer than when it's colder and that's well established. So therefore you would actually expect the snowfall to increase at high altitudes until it gets past the freezing point and then starts to melt and that's not just been observed in Alaska, that's also been observed in Antarctica and in Greenland.

But the sides of Greenland and Antarctica which are lower down and near freezing where the temperatures have come up several degrees those have been melting very, very rapidly, more rapidly than any theory has suggested. So it is in fact consistent with what the models predict that you're building up snow on the top and you're reducing it on the sides and the question is who is winning and NASA has been able to tell us that. This is amazing because the gravity associated with the mass on Greenland is sufficient that if you fly two satellites near each other up in space over Greenland, and they're called Grace, they're the two, you can actually measure them separate by metres because your telemetry is that good and they actually have calculated back that the melt rates on the sides are about 4 times the build up rate on the top. All of that is consistent with theory.

JENNY BROCKIE: Okay, Case?

CASE SMIT: Just on that for a moment, I didn't understand that Greenland lower altitude temperatures had increased by several degrees. I understood that at most it increased by 1.5 degrees.

PROFESSOR STEPHEN SCHNEIDER: On that order. I agree. It's on that order of 1 to 2.

CASE SMIT: So you were just exaggerating.

JENNY BROCKIE: It's a reasonable point, were you exaggerating?

PROFESSOR STEPHEN SCHNEIDER: No. In some parts, in some parts of the arctic it's way more than several degrees and I don't remember precisely what the exact numbers are and you can't use an exact number for Greenland anyway, it's a big place and it's different in different parts.

JENNY BROCKIE: Okay, let's talk about modelling because modelling's been mentioned a number of times here tonight and Raq, I know you've got a question about modelling that you want to raise with Stephen, what is it?

RAQIBUL HASSAN: Well as I've explained I do believe the anthropogenic link.

JENNY BROCKIE: Anthropogenic meaning?

RAQIBUL HASSAN: Man made climate change but if someone asked me about climate change I'd say I'm not 100% certain because you in the IPCC reports you yourself note that it is very likely and I think it shifted from an 8 out of 10 to a 9 out of 10 chance that it will actually happen and I understand that is largely due to the modelling that's used to model such a complex system which is our climate. I was wondering if you could explain further about that uncertainty and why it is there and what it means?

PROFESSOR STEPHEN SCHNEIDER: So a question about how to assign confidence is excellent and I have to admit I have a dog in that show because in the year 2000 there was a guidance paper on uncertainties in the IPCC which I was the co"‘author, Richard Moss and I, so, you know, this was not Fred Singer or some sceptic who came along and said listen, IPCC, you better address uncertainties, don't just give us conclusions, tell us how much you believe they're true, that was me.

So I have long been a believer that you have to frame things in terms of the uncertainty associated with them. So what we suggested was based on a large number of studies that were made of people's mental map of a word like likely, you know it's amazing it varies by a factor of five what people think the probability is of likely. Some people think likely is 99%, some people think likely is 25% and in fact if you're talking about what does the word likely mean for something dread like a cancer"‘causing food additive, people think 5% is likely. It's not likely. It's risk. Remember risk is what can happen, that's the consequence, multiplied times the probability. So we have to separate those. You can certainly decide to buy insurance for only a 1% chance your house will burn down. So it's not very likely but the consequence is so high that we buy insurance. So we make what's called a risk management judgment.

So how do we do that in IPCC? So what I insisted was that when we're talking about what do we think the probability is that humans have been, as I said, part of the story, we have got to have a quantitative scale to link words like likely. So what we did, and what our guidance paper said was something between two thirds and 90% defines the word likely. Now others can have a different meaning but scientists can legitimately disagree about how likely it is but it would be irrational if we had a different mental picture of what probability we each meant.

So what we tried to do with our guidance language is to be consistent in what the word meant. So if you use the word high confidence it means greater than 9 out of 10 - very high confidence greater than 9.5 out of 10. So is it true what we estimate? Not necessarily because a lot of uncertainties you simply don't have the data and you don't therefore have that higher confidence. But at least we're consistent in the language. So when you mentioned that the probabilities assigned from say the 2000 IPCC report up to the 2007 for the probability of human"‘induced change, it did go up from something like 80 to 90 and that's not because of the models themselves, it's because we had extra accumulated data which gave you a chance to calibrate the model's prediction relative to that data and when it agreed fairly well that statistically allows you to increase your confidence.

JENNY BROCKIE: Katy, you had your hand up.

KATY BARNETT, LAWYER: I'm not a scientist I can't express any opinion about the science.

JENNY BROCKIE: You're a lawyer.

KATY BARNETT: I'm a lawyer so sue me.

JENNY BROCKIE: But you are the daughter of two scientists, aren't you, and you're married to a scientist.

KATY BARNETT: So.

PROFESSOR STEPHEN SCHNEIDER: So you're surrounded.

JENNY BROCKIE: Away you go.

KATY BARNETT: I'm surrounded. My problem is with the rhetoric of this. I made the mistake of confessing that I wasn't sure one way or the other. You would think that I killed small children, essentially, all these people piled on me, said that I was a fascist, a kin to a holocaust denier. A prominent politician here wrote anyone who denies climate change is occurring is akin to a holocaust denier which I found incredibly offensive. Um, anyone who questions it"‘

JENNY BROCKIE: Now, you're not the only one who's raised this and I find "‘ Jon, you've raised this, you're an environmentalist who wrote about your doubts about climate change and you had the same experience, yeah.

PROFESSOR STEPHEN SCHNEIDER: I don't agree with that framing either.

JENNY BROCKIE: Let's just hear Jon's story because I think it's interesting.

JON WOODLANDS: I've got quite a long history in the green movement but I think global warming and anthropogenic global warming is a curly one and I still have quite strong doubts and yeah, I've written two or three articles and been threatened "‘ there's people in my town in Melany in Queensland that literally cross the street when they see me coming simply because I've presented an alternative argument and I've raised the question and "‘

JENNY BROCKIE: And Leigh, you published the article in the paper.

LEIGH ROBSHAW, FREELANCE WRITER: Yeah, and I was also abused and threatened and defamed in our small town because I'd published the article. I didn't even say what my opinion was but just because I published it.

JENNY BROCKIE: I find this really interesting.

PROFESSOR STEPHEN SCHNEIDER: It's very sad.

JENNY BROCKIE: I wonder to what extent this is part of the problem that has emerged around this, that you've got people unable to have a debate, unable to actually or feeling they're unable to have a debate or express their views. Some of you who felt that to pop your heads up and say that you were climate change sceptics or sceptics about man made climate change led to you feeling ostracised. Stephen, I said I'd give you a chance to respond to that. Do you think that that is a problem in this debate, that people are finding that, you know, there's a kind of political correctness one way or the other about what you should believe rather than having a genuine debate?

PROFESSOR STEPHEN SCHNEIDER: I actually hate that when it happens and I'm very sympathetic with what happened to you because I can assure you I get death threat emails all the time and I know exactly what it feels like to get these kinds of things. In fact I decry the destruction in civility that's been happening around this issue and in the US over issues like health care and creation teaching in schools and things like that because if people can't maintain a civil dialogue how are you going to run a civil democracy and I mean I get stuff like "You communistic dupe of the United Nations you want to create a world government that's going to take away our religious and economic freedom, you're a traitor, you should be hung." I have dozens of such emails. That's not fun and my son got one today like that and he called and told me that. So this is not "‘

JENNY BROCKIE: Your son got one today?

PROFESSOR STEPHEN SCHNEIDER: Quite as bad as this but "How can you tolerate living with your father", this kind of stuff. We get that kind of stuff. There's no place for that in civil society because scientists also need to be engaged by helping people understand risk and when you're in this constant set of combat then how do we have any chance of talking to each other in a civil way, which is why I agreed to do this program.

JENNY BROCKIE: Katy.

KATY BARNETT: I was just about to say the thank you for actually engaging in dialogue sensibly and not "‘ basically not demonising anyone who dares to raise a doubt.

JENNY BROCKIE: You used to be a believer in man made climate change.

KATY BARNETT: No.

JENNY BROCKIE: To some extent?

KATY BARNETT: I was never quite sure to be honest. I don't know enough. Um, the problem is from my point of view that we've had, I suppose, the case for the prosecution in legal terms, you know, this is how worst"‘case scenario. It's really hard to stand up and say okay, I'm going to knock that down in this present climate, excuse the pun, but yeah. It's really hard to stand up and go okay, I'm a scientist who is going to try and disprove this.

JENNY BROCKIE: I'm interested though in this question of trust because it's come up with a lot of people here about how much they trust the data, how much they trust the scientist. You don't trust scientist, Chris, why?


CHRIS MACDONALD: Well it was very interesting hear you talk a moment about ago about scientist like the median, a moderate tendency. What I find suspicious is that I have not heard, and I watch a lot of media, one of these moderately minded scientists come out and hose down the Doomsday scenarios being pedals by environmentalists and our politicians. I'm not speaking of you yourself, sir, but your industry, your lobbying, the lobby of which you are a part including a lot of people I'm sure you have arguments with are actually saying X plus Y all the way to we have to chuck out industrialisation.

JENNY BROCKIE: So being absolute and certain and you want them to be less certain or you want "‘

CHRIS MACDONALD: I would like to hear people in your business admit some doubt.

PROFESSOR STEPHEN SCHNEIDER: I don't know any IPCC scientist who said we should chuck industrial civilisation out. That's a straw man, where did you get that?

CHRIS MACDONALD: I have never heard one of them stand up and say this politician should choose their words more carefully that it's not that disaster, that this environmentalist should be more moderate in their language because they're being too extreme. I have not heard one IPCC scientist say that.

PROFESSOR STEPHEN SCHNEIDER: Please read my book you'll see where I've been doing this for 40 years and I'm not alone in doing that. I think it would be irresponsible for us to leave out better cases and it would also be irresponsible to leave out worst cases. It is not a scientist's job to judge whether or not the risks are sufficient to hedge against any of these possibilities. It's only our job to report risk and that's why we have so many rounds of reviews. I was talking about when I said scientists gravitate to the middle - I was talking most IPCC scientists. They're not typically very articulate and they're not the ones you're seeing on the media very often.

CHRIS MACDONALD: You were very quick to comment on what you called bias language earlier, I think a scientist in your position could speak up against bias language even in areas where it actually contributes to your industry.

JENNY BROCKIE: It's an interesting point, Stephen. It is an interesting point that the scientists could enter the debate once it becomes politicised and perhaps distorted in that politicisation, the scientist could pop their heads up more and say hang on a minute, you know, what we do know is this, what we don't know is this.

PROFESSOR STEPHEN SCHNEIDER: I can speak for myself that's exactly what I do but I can also tell you, and so do most of the colleagues that I respect. Not everybody. There are people who understate and there are people who overstate. The other problem is, don't forget the media filter. Media gets end of the world versus good for you boxed extremes. Like it's a trial, you know, we've got guilty and we have innocence and they will set that frame. So if a scientist is speaking in a bell curve, right and you allow some probability of a really nasty outcome and some probability of beneficial outcomes and every speech I give, go on YouTube will you find them, you will see I do this, I have no control about the fact that because I have concern about the more serious scenarios, and I do, I don't want us to fall into that trap, I don't take 10% risks with planetary life support system. That's my personal view. That's my personal values and I always say that.

The point though is if it's then reported that I believe that it's certain that it's going to be in the worst case that's a misframing of what I've said. Just as when I'm arguing with other people who are more conservative and they allow a small probability that they think I'm right and they have a larger probability that things are milder and then they get boxed into the frame that they only think that it's mild that's not fair to them either.

It's because when you go through the filter of this kind of advocacy, end of the world and good for you which in every speech again, go look it up on YouTube, you'll see me, I say the two lowest probability outcomes, that's a very bad way to convey the nature of meaning because all it can do is confuse people and create the polarisation that's led to those of you who have gotten the hate mails from getting them because people get locked in those polarisations.

JENNY BROCKIE: Jessica, why are you a climate sceptic?

JESSICA BERRY, STUDENT: Look, Stephen, I think there is just "‘ it is just such a complex issue and, um, I agree that the sound byte journalism is a problem. So my question to you, I have two question, first one is for those of us who are keen to get past those 5"‘second grabs that we see on the evening news but are not scientists, are just the every man, can you give us a couple of sources of good information that make it very easy to understand what is obviously a complex issue and then my second question is knowing what you know, are you afraid?

PROFESSOR STEPHEN SCHNEIDER: Okay, very good questions. There are many good websites. There's absolutely no such thing as a perfect site. I get very nervous about elliptical blogs, those which are so polarised into one or the other because generally they're very good writers and if somebody already pre"‘believes them they're very exciting but then again what we lose is a civil dialogue. You can read Environmental Protection Agency things, you can go to universities, there are a lot of things.

I would argue, some of you may smile, that one of the most credible sets of information is to read the IPCC reports. They drip with caveats. In fact it's darn hard to read because they're not very well written but there are a lot of people who do it. Private books that are not peer reviewed are much more likely to be elliptical and blogs. So there are plenty of websites out there.

JENNY BROCKIE: We do have to wrap up. How many people here have shifted ground at all tonight? Has anyone shifted their ground - One hand up over here, yes, one up there, why?


WOMAN: I was sitting on the fence and really there's just been so much technical jargon from both sides and so much almost hatred towards each other, um, I was hoping to get more information for me to make up my own mind and I feel more information and quite simply the one that was a gallon of water in and a gallon of water out but everyone seemed to agree there was this 3% that was man made and, um, that had to go somewhere and as simplified as that was I feel as though man has impacted.

JENNY BROCKIE: Dave, David, what about you?

DAVID CLARK, GOVERNMENT EMPLOYEE: Doctor, you've put some great arguments forward and we've got two sides of the story and yes, we get your media bytes as sceptics, as layman, as normal member of the public there's enough information out there to seek if we wish to seek it. What makes us believe you over the man that stands next to you? Now we don't have a scientist from the other side because it would have been probably impossible to run the show.

JENNY BROCKIE: Well there's a whole audience of people from the other side.

DAVID CLARK: And we got that sort of argy"‘bargy sort of thing. How do we believe you over the others when both argue with credible points? You both have excellent information there and it makes it difficult.

PROFESSOR STEPHEN SCHNEIDER: Very good question. I teach a seminar for freshmen and sophomores called environmental literacy and how can you discern the quality of an argument? Watch out for the myth busters and the truth tellers. Anybody who's got the answer almost certainly is not credible on a complicated problem. Who's talking in ranges and bell curves and wheels of fortune, yes, that's self"‘serving, I am and that's because the nature of our scientific understanding, so is IPCC.

So I think the best guide for you is when there's a complex problem remember you can break it down into well established bits where we do have some things that are very likely, competing explanations like Greenland is melting but exactly why, we don't know why, and speculative we really don't know what's the cloud feedback amount going to be and when people talk like that they're much more likely to be credible when they tell you that they have, you know, the smoking gun that proves or disproves, very rarely in complex science is that true.

JENNY BROCKIE: Jessica, are you still wanting your question answered?

JESSICA BERRY: I think it might be a good way to simplify all the jargon and to put it into perspective that everyone can understand. Knowing what you know and having studied for as you say 40 years, are you afraid? Are you afraid for your grandchildren?

PROFESSOR STEPHEN SCHNEIDER: Well of course that's a personal judgment about what, I'm afraid that we have a very uncomfortable probability which to me is more than 10% of some pretty nasty outcomes. We also have, you know, 10, 20% chance that there won't be very many nasty outcomes and everything else sort of in between. I'm more worried about what the US Pentagon officials said which is that climate change is not the cause of security threats but it's a threat multiplier because you don't want to sit there in already stressed areas and then add stress. I worry more about that than I do about most other aspects of climate.

You know, if we raise the sea level many metres, yeah, we're going to move, we're going to move billions of people and trillions of dollars but that's replaceable. I'm more worried about species extinction because that's irreversible. If you warm up you drive them off the tops of mountains. But I also worry about badly implemented climate policy. Again, go read my book or go look at any of my YouTubes and you will find out that I always point out you can't just impose a cost on energy overnight - although we have to eventually do that - you have to have principle in my opinion, because for me it affects the quality of my pinot noir for a poor person it might affect the quality of their protein. But I do not want to hold the sustainability agenda of the planet hostage to that. We should not subsidise poverty by artificially low prices of commodities like food and energy. Get the price to include all the cost but we do have to have side payments to help those people through a transition and I mean I don't know coal miner or any auto worker making a big car who does it to screw up the climate but they may be crew screwing up the climate. We've argued that.

But if so, that may not be allowed to be continued very long but you can't just hang them out to dry. You've got to do something. So I would be afraid of either having those groups disadvantaged by policy just as I'm afraid that the small island states will have to move and lose their homelands because they're disadvantaged by sea level rise and we therefore in the planet will have to deal not just with the magnitude of the climate change and it's not just the consequences of that but also the consequences of the policies and they involve not just preventing climate change but dealing with people who are effected by those policies. That's part of the complexity which is so difficult to manage in a world of a bunch of nation states where people can't agree. That's what I'm afraid of.

JENNY BROCKIE: Okay, we have to wrap it up but we can keep going online. So even though we have run out of time here, hop online if you want to continue the discussion. Stephen Schneider thank you very much for your time tonight, and my thanks too very much to our audience of sceptics, a few of you seem to have shifted a bit of ground. We'll find out a bit more later about how much. Join us again next week, until then goodnight.