Source: BBC Radio 5 Live
URL: N/A
Date: 31/01/2014
Event: Andrew Montford: the climate models "don't agree with what's happening in the real world"
Credit: BBC Radio 5 Live
People:
Stephen Nolan: Prince Charles will be visiting people affected by the flooding on the Somerset Levels next week. The Prince was speaking in an award ceremony at Buckingham Palace. He described climate change deniers as "the headless chicken brigade", who are ignoring scientific evidence. It'd be good to get your reaction to that tonight, actually - 0500 909 693. Here's what he said - he says there was a "barrage of sheer intimidation", we're told by "powerful groups of deniers that the scientists are wrong, and we must abandon all our faith in so much overwhelming scientific evidence."
What do you think? Are you still unconvinced? Is Charles right? Is it wrong to challenge evidence for climate change? Text - 08508. A text's come in, actually: "Yes, climate change deniers are bonkers", said this texter, "you can't deny climate changes, otherwise explain the Ice Age and what we have now. They're denying man's involvement". Dr. Paul Williams is a Royal Society Research Fellow at the University of Reading. Hello, Dr. Paul.
Paul Williams: Hello, Stephen.
Stephen Nolan: Hello, there. You contributed to a UN report last year that claimed scientists are almost certain that climate change is happening and humans are to blame. Andrew Montford is a writer, blogger and climate change sceptic. Hello, Andrew.
Andrew Montford: Hello.
Stephen Nolan: Right, it will be interesting to hear you two talk to each other. Dr. Paul, convince us that Prince Charles is right.
Paul Williams: Well, it was an interesting expression, wasn't it - "the headless chicken brigade" - and I think that's probably not the sort of language that scientists would naturally speak in, so I wouldn't necessarily have put it that way, myself. But, I mean, look, I think the point that he was making is pretty clear. The scientific evidence for climate change is really piling up around us, and it's been stacking up, year after year after year, for decades, now, and it's absolutely relentless. And, as scientists, we're constantly refining our knowledge and getting new pieces of that jigsaw.
And I think what Prince Charles was saying is that it's got to the point now where that mountain of scientific evidence is so high and so immense that to deny its existence would be foolish. And I think people who ignore that evidence about climate change are living in a fantasyland, really. And if that's the point that Prince Charles was making, then yes, I think I would tend to agree with -
Stephen Nolan: But this new evidence, this new evidence that you talk about, Paul, it's coming forward - what is it?
Paul Williams: Um, I mean, it's countless, independent strands of evidence, really - it's coming from satellites and from thermometers, and from tree-rings and from satellite measurements of sea-ice decline, sea-level rise... I mean, it's not just a single thermometer stuck in someone's garden, you know, it's thousands - well, really, countless - pieces of evidence. And they're all telling the same story, and that's why we're so convinced about it - it's that level of robustness that gives us the confidence.
Stephen Nolan: Yeah, but where's the story that is pointing to humans to blame?
Paul Williams: Well, this is, sort of, physics - atmospheric physics, really, that we've known about for a century. Um, no-one is denying - I think, not even the staunchest climate deniers, these days, deny that carbon dioxide is a greenhouse gas. When it gets into the atmosphere, it traps outgoing heat - heat, leaving the surface of the Earth, going up into the atmosphere, gets trapped by the CO2, and that has a warming effect. And I think the basic science there is very robust and very clear, and I don't even think the staunchest sceptics are refuting that, these days.
Stephen Nolan: And yes, you're one of the people, Andrew, that Prince Charles is describing as a "headless chicken". Bonkers!
Andrew Montford: Yes, quite possibly, but I don't think anybody takes what Prince Charles says terribly seriously. Um, let's just look at some of what Paul just said. I'm with him on certain things - I agree that carbon dioxide is a greenhouse gas, and is expected to warm the planet a little bit. Um, the idea that carbon dioxide is going to cause a lot of warming is still rather tenuous. The basic physics, as he says, of greenhouse gases, is fairly clear, but to get to dangerous levels of warming - which is what scientists are telling us we're going to see - involves a whole lot of other effects that are much less clear.
I think you picked on a very good point, there, when you said: okay, where's the evidence of a man-made influence on the climate? We have seen some warming. But you can't - that's evidence that the planet's got a little bit warmer, and, as everybody, I think, now knows, we haven't seen very much warming for getting on for 20 years, now. Um, but there is no evidence, as such, for man-made influence - we can't, in statistical terms, look at the warming we've seen and say that it's doing anything very different. To get to the idea that mankind is involved in the warming that we saw at the end of the last century, we have to use computer simulations of the climate.
Now, the six million dollar question is: are those computer simulations right? And, at the moment, they look very much as if they're not. The computer simulations are saying that we should have seen quite a lot of warming since the turn of the century, and we haven't, okay. We also know the most recent batch of computer simulations, which are called the CMIP5 models, which were in the last UN report on the climate, we know that they don't include some very important up-to-date data on the effects of pollution -
Stephen Nolan: Okay. Dr. Williams?
Andrew Montford: - so they're running too hot.
Stephen Nolan: Paul?
Paul Williams: Yeah, well, let's have a bit of a chat about climate models and what goes into them. Um, I mean, we've known for a couple of centuries what the equations are that describe motions in the atmosphere and ocean - we've known about them since the early 1800s, and they're called the Navier-Stokes equations, for people who are interested in that sort of thing, and they're exact equations. No-one's ever done an experiment on a fluid where they've been incorrect, unless you're talking about getting towards the speed of light, or that sort of thing, but that's not what we're talking about, here. Um, now, I guess I have a question for Andrew, really, which is: you find the models to be lacking, in certain respects, and I just wonder, you know, which part of the model do you think we've got wrong? I mean, what are the terms and conditions-
Andrew Montford: Yes, I mean, as I say -
Paul Williams: - is it the Coriolis forces, is it the pressure gradient, is it the viscosity -
Andrew Montford: Okay, I mean, let's talk about that. I mean, the two areas that jump out, to me - one is the effects of pollution, the - aerosols is the technical word for them - the climate models are suggesting that the effect of pollution is quite large, but the empirical measurements are suggesting that it's really much smaller. Now, that will mean that the models are wrong, and that they should run a lot cooler than they do. That's one thing. We also know that the effects of clouds is almost impossible to simulate in a computer model, so we know that, um, the cloud simulations are speculative at best.
Stephen Nolan: And that's what these are, Paul Williams - you can't get away from it. They're computer models, to estimate how the climate will change, right?
Paul Williams: Yes, I mean, the only exact model of the climate system is the climate system, and a model, by definition, is going to have some level of approximation in it. And Andrew's absolutely right, in the sense that we can't solve these Navier-Stokes equations exactly, just because we don't have a fast enough super-computer. And so what we do instead is: we formulate approximate models, and there are different ways of formulating those approximations, and the clouds, as Andrew says, are very important. But the fact remains is that all of the dozens of independent climate models that have been made, around the world, are all showing the same thing - they're all showing that greenhouse gases cause the temperature to rise.
Andrew Montford: Yeah, but they may agree with each other -
Paul Williams: Yeah.
Andrew Montford: - but they don't agree with what's happening in the real world. And this is the point, that, you know, the world should be warming at 0.2 degrees per decade, and we haven't had any warming at all for the last two decades. You could argue that that's just natural variation and, you know, warming will pick up later. But at the moment it looks extremely unlikely that that is the case. I mean, if we have - if it is natural variation, then we should - maybe the warming that we saw at the end of the last century was just natural variation as well.
Paul Williams: Well - yeah, it's important to remember, of course, as well, that the last decade has been the hottest in human history, despite what has been called a pause in the warming -
Andrew Montford: Yeah, it's plateaued, it's plateaued at the top. You know, that's fine, we agree on that.
Paul Williams: Yeah, yeah. But, I mean, it's untrue that climate models don't simulate occasional pauses in warming. If you attempt a simulation of 20th century climate, using an individual climate model, it will stall, and -
Stephen Nolan: Okay.
Paul Williams: - for a few years at a time, and then they will get back to increase [?] -
Andrew Montford: Yeah, I mean, there was quite a prominent climatologist, Hans von Storch, who said, at the end of last year, that the kind of pause in warming that we've had appears in less than 2% of climate model runs. So it is extremely unlikely - I mean, normally, once you get below 5%, you know, the statisticians say "Well, you know, it's - it's disproven" -
Stephen Nolan: Okay. We're going to have to leave it there, but thank you very much indeed, Andrew Montford and Dr. Paul Williams, thank you.