Source: YouTube
URL: http://www.youtube.com/watch?v=gto8VTGhtZs
Date: 02/11/2011
Event: Richard Black gives a presentation on impartiality and reporting climate change
People:
Richard Black: Thanks very much, David. Yeah I mean, personally I view the Jones report as basically quite empowering actually, because what it basically tells us in a nutshell is that, where there is a genuine debate, let's reflect it. Where there isn't a genuine debate, let's not pretend that there is. So, if we're going to talk about things like due impartiality, then we need to know, I think, what the sort of weight of evidence is behind various things in climate change, so I'm just going to spend a few minutes just going through some of the things that you may have read, heard, perhaps even said in editorial meetings and see what the evidence actually tells us about those - any of those look familiar?
[Projected on a nearby screen:]
So for the first of those we need to go back two years, just before Copenhagen in 2009 when we had two things really, there was the Climategate, the hacking of emails from the University of East Anglia, and the discovery of errors in the Intergovernmental Panel on Climate Change report, particularly an error on the melting date of Himalayan glaciers.
So lots of fun for anyone with a satirical bent, and produced an awful lot of, sort of, noise and so on, and the fact that it happened before Copenhagen can't have been coincidental. But since then there are a number of reviews that have been done into various aspects of this, and I thought it's just worth running through what some of them actually found. I've just picked out the five what I think for us are the most important.
So the first was a House of Commons Science and Technology Committee, March 2009, on the Climatic Research Unit at the University of East Anglia, and what they found basically was that there was no manipulation, that scientists should be more open, they emerged with their reputations intact.
Lord Oxburgh, a month later, commissioned by the University of East Anglia, and he concluded more openness is needed, they ought to have involved professional statisticians more, but that there was basically no impropriety.
The Dutch government asked its environment assessment agency to do a report into the IPCC because there was an error in there about the amount of Holland that would be underwater as a result of flooding. So they reported, and their conclusion was basically the IPCC should be more transparent, there was nothing to undermine the science of anthropogenic global warming, and it blamed itself for giving the IPCCs duff information about the flooding.
The most important of the UK reports, the Muir Russell, same month, transparency needed, there was no malpractice, science reputation intact, and the big one, the Inter-Academy Council review of the IPCC, and they said it should be more transparent, some reforms were needed, but there's nothing that changes the basic scientific picture of man-made global warming. So something of a pattern emerging there, I think.
I was in a meeting a couple of weeks ago where Jon Snow was chairing, and he said in his judgement, both at Channel 4 and in the wider media, climate change wasn't being reported because of Climategate.
Well, looking back on this, and giving a perhaps not very scientific analogy here, the heat suggested basically that the climate scientists had been buggering the choir boy, and what it really transpires is that they mislaid the application forms to join the choir. And I think if we're basing, any of us are basing decisions not to do climate change on the basis of Climategate, this, I think, shows us that that's a bad judgement to make.
Okay, second question: is it warming? Well, we have stacks and stacks of weather stations all around the planet that are gathering data. They're analysed by three main centres, two in the States, one in the UK, and as you see, all those three curves are pretty much the same, and they all indicate warming. From 1979 they're joined by completely independent satellite-based records which look down upon the earth. So I think it's pretty unequivocal from that that the earth is warming. But if you still had any doubts, a little under two weeks ago came news from another independent group which was set up by a group of scientists, some of whom were sceptical about the temperature record. This was applauded by sceptics; they thought it might find something completely different. They reported their results for land-based warming two weeks ago, and what does it say? It's the black curve right in the middle, and it's virtually the same as all the others.
Now I think it's important to point out that this is about as good as it gets in observational science. There are lots of conclusions made from Earth observations which consist of one satellite, or one expedition that goes somewhere for a few months and maybe goes back five years later. This is thousands of weather stations around the world, all sending their data in, augmented by multiple satellite data. This is as good as it gets in observational science. So if anyone says that the Earth really isn't warming, they'd better come up with some pretty powerful evidence against that.
But, did it stop in 1998? This is something that is often said, and again this is an argument that came into vogue just before Copenhagen. And the argument was that if you took data points between 1998 and 2008 you see a net cooling. So what does that mean?
Well, a few months ago on my blog I just did a very simple non-statistical exercise. I said: well, if warming stops in 1998, then by any common sense definition, it ought to also be true that it stopped in 1997 or in 1999. These things really don't make much difference where you started from if it's a real trend. So let's take the most recent ten-year periods that you can have so 1991 to 2001, 1992 to 2002, and let's see what you get. This is drawn from the NASA record, but you could take any of the others. Only one of those ten year periods shows a cooling. So if you're gonna say that warming stopped in 1998 and that's there's been no warming, that's the definition of cherry-picking your data.
What this also shows is that you shouldn't do this thing of taking one year to another. It's a ridiculous thing to do, because there are so many natural variations in the climate system. What you should do is take an average. This is from the UK group, and what you can see as you come up here is that you're averaging out all of these variations but as you get here, you could make a case for saying that global warming's plateaued, but if you're gonna do that, you also have to say that it plateaued there, and there and there. And you may have seen an article in the Daily Mail, sorry, the Mail on Sunday, over the weekend that showed that the Berkeley group showed that global warming had stopped. If anyone's interested I can demolish that for you later on. But essentially you need to have a longer data set before you can make any definitive statement about global warming having stopped. It certainly looks as though we're going through a period of relative plateauing, but that doesn't mean it's all over.
So what's causing it? Is it CO2 or something else? Here's a list of some of the most important things that affect global temperatures. Some of them man-made, some of them natural, some of them cyclical, some of them long-term trends, some of them just things that just change year by year. What makes the picture even worse is that these things influence each other. In an ideal world, if you were doing an experiment in a lab, you'd take out everything but greenhouse gases, you'd change greenhouse gases, see what you get. You can't do that in the real world. So, with that very complex picture, what are some of the things that lead scientists to put the primary finger on CO2 and other greenhouse gases.
One thing that's often been said is that it's down to changes in the sun's output. This comes from a scientific paper that was released a few years ago. The top graph, cosmic ray count, is a kind of measure of solar activity basically, because an active sun blocks cosmic rays more than a quiet sun. So you see it's going up and down over the last 25 years, but the global temperature keeps going up - a powerful argument against a dominating solar influence at the moment.
These are temperature graphs from the upper atmosphere, the stratosphere, and what you'll notice is that that's getting cooler. Now if the warming was due to something like, for example, extra heat from the sun or extra heat coming up from the oceans, you might expect to see the same thing happening throughout the atmosphere, but we don't. We see warming at the surface, cooling in the upper atmosphere. That begins to look like some sort of greenhouse effect, some sort of insulation that's actually changing the distribution of heat in the atmosphere. Something rather like greenhouse gases, for example.
This may be the least satisfying of all the reasons. David Shukman's often made the point, and I completely agree with him - that there's a qualitative difference between evidence from observation and evidence from models. But nevertheless, the climate models that are in use, if you take out greenhouse gases and all the other things that humans are doing, they predict that you should see a temperature curve like that, but we don't, we see a temperature curve like that. So, how convincing you find that is up to you, but there it is. And perhaps the other thing is, we know that carbon dioxide and other gases are greenhouse gases, you can prove that in the lab, we've known that for 150 years. And there's the curve of carbon dioxide, so, you know, in a simple rational world, if that doesn't change, you would expect that to be driving some warming.
So what does the future hold? I mean, Alejandra's going to talk much more about this in terms of impacts on societies and economies and so on, but just in terms of what the models are actually telling us about - maybe I'll have to aim this very precisely, I don't know - okay, good. Alright, so this is the output from some of the climate models that are used by the IPCC, and you'll see there's a range up there of possible warmings. Now, you have to make lots of assumptions about how society's going to go, what's population growth going to be like, how much of our energy are we going to get from fossil fuels - all kinds of things - so actually making these projections is not very easy, not to mention the physical issues, that we don't perfectly understand the climate system.
Here's something from the IPCC report that presents some options, and if you take these sort of low economic growth, moderate growth, high economic growth, and you see at the high end you're seeing temperature changes of sort of 8 degrees in parts of the world. Low economic growth, you're still seeing significant changes in the Arctic but perhaps not quite so bad elsewhere.
Recently there's been quite a lot of interest in this concept of tipping points. You may reach a certain point where you basically go into a different state of something or other. By definition you're trying to predict the unpredictable, so it's really tough, but a few of the tipping points that people have come up with are for example the melting of the Greenland ice sheet, the melting of the West Antarctic ice sheet, die-back of the Amazon rain forest, and perhaps changes to the Indian monsoon. And some of these could be irreversible. So we're not in an era of certainty here with this fifth question, but we are into an area of risk management. Right, so I'll leave it there.