Source: BBC Radio 4: World at One
URL: N/A
Date: 27/09/2013
Event: Bob Carter: the IPCC's 95% probability is "hocus-pocus science"
Credit: BBC Radio 4
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Shaun Ley: The World at One - this is Shaun Ley with 45 minutes of news and comment. A long-awaited United Nations report on climate change has concluded it's 95% certain that human activity is the main cause of global warming. We'll hear from one of the scientists behind the report, and a prominent critic.
Bob Carter: No government tries to predict or stop an earthquake or a volcanic eruption. Similarly, no sensible government would dream of trying to - in inverted commas - "stop climate change".
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Shaun Ley: The last time the scientists on the Intergovernmental Panel on Climate Change - the IPCC - reported, they said it was "very likely" that man's actions were the principal cause of a warming planet. This morning, six years on, they say it's "extremely likely". It's a simple phrase but it follows a big programme of work involving authors in 39 countries, and as an official body, there was quite a bit of haggling in the hours preceding publication, though, a process in which government-sponsored scientists have to agree every phrase.
It's then down to the governments to use the findings as the basis for a new treaty for tackling climate change. The Energy and Climate Change Secretary, Ed Davey, says it will strengthen the UK government's demand for tougher international targets to reduce carbon emissions.
Ed Davey: This piece of evidence that we're seeing from Stockholm is probably the most robust, rigorous, most peer-reviewed piece of science in human history. I think it's put the question of whether climate change is happening beyond doubt. We've got to stop debating this issue as if we're some members of the Flat Earth Society and get on and act.
Shaun Ley: Even some of those who support the panel's findings, though, are critical about the way it operates. Lord Stern, who wrote a report for the last government on the economic effects of climate change, has complained about "filtering and haggling" leading to bland conclusions. That's nothing to the dissatisfaction felt by Bob Carter - an Australian geologist and oceanographer, he accuses the IPCC of being unscientific in its approach. He's contributed to an alternative non-government group calling itself the NIPCC.
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Bob Carter: The difference between the two reports is this, that the IPCC has an idea - it's not actually their idea, it was why they were set up - they were told to go away and consider the business, not of climate change in the round, but of climate change caused by human greenhouse gas emissions. So what it does is it goes out and looks for evidence for humans having a dangerous impact on climate. Now, real science doesn't work that way.
Now as you probably know, science proceeds in general by setting up what's called a null hypothesis, which is the simplest hypothesis. And that is: we look out the window and we see, every day, changes in the weather and, in the longer term, the climate - the distribution and patterns of nesting and flowering, and so on, in animals and plants. So we know the real world is variable the whole time. The null hypothesis, therefore, is that those changes we observe are due to natural variation. And the NIPCC report tries to invalidate that hypothesis. And the really interesting thing is that after looking at several thousand papers, just like the IPCC, we come to the opposite conclusion. One of our conclusions is: climate has always changed and it always will - there is nothing unusual about the modern magnitudes or rates of change of temperature, of ice volume, of sea level or of extreme weather events.
Shaun Ley: The IPCC said today that having previously said it thought it was "very likely" that man was responsible for global warming - the activity of man being the main reason for global warming - it now says it's "extremely likely", 95% certain. That's a very different conclusion to yours.
Bob Carter: The problem with what you just said to me about 95% probability - it's hocus-pocus science. In science, the phrase "70% probable" or "90% probable" have definite meanings. They imply controlled trials, they imply numerical, quantitative information, objectively assessed. If you ask the IPCC, they will tell you that when they use the term "95% probable", it is based on the expert opinion of a group of people gathered around the table. It is completely wrong to use probability terminology to describe what is - albeit an expert - opinion.
Shaun Ley: Yet isn't it hard for you to put your counter position, when you see that this report is based, as it says, on the work of 209 authors, 50 editors from 39 countries - 9,000 peer-reviewed scientific papers have been used to draw up the report. The scale of the people who have contributed to this gives it a lot of credibility.
Bob Carter: Well -
Shaun Ley: I mean, how many, you know, authors have been involved in your work, for example?
Bob Carter: There are about 47 scientists, scattered around the world, who have contributed to the NIPCC report. They are entirely without conflicts of interest. They have no relationship with government authorities or bodies. They are giving you a genuine independent, if you like due diligence audit of what the IPCC is up to.
Shaun Ley: The IPCC is, as you say, funded by governments, it's funded by public organisations of various kinds who help to pay for the scientists, and so on. You can't do this off your own back - you have to get help and support. What sort of help and support do you get?
Bob Carter: It is largely done off our own bat. The organisation who prints and edits and organises it is a think tank in Chicago, a libertarian think tank called the Heartland Institute, and they accept donations from family foundations specifically to fund the NIPCC exercise. There is no industry money in it. Even more importantly, there's no government money in it or environmental lobby group money in it.
Shaun Ley: What then does your group think should be done - if anything - to address the consequences of these changes in temperature? Because if changes of temperature are happening - whoever or whatever causes them, whether they are entirely natural or man has contributed to them - they have consequences.
Bob Carter: It's clear - I live in Australia, we have catastrophic bush fires, floods and cyclones, and it's very clear that we do not - western governments do not handle emergency weather and climate events like that as well as they should. So, is there a need for a United Nations body to be set up to advise us on all of that? No, there isn't. Is there a need to improve the way we handle natural disasters? Yes, there is a need to do that. But it's by continuing but improving what we do already, which is to adapt to the change, as and when it happens.
No government tries to predict or stop an earthquake or a volcanic eruption. Similarly, no sensible government would dream of trying to - in inverted commas - "stop climate change". It is a ludicrous idea.
Shaun Ley: Bob Carter. So how does the panel respond to the criticism that the conclusions are the result of government influenced haggling? Peter Stott from the Met Office is one of the IPCC's lead authors of its report.
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Peter Stott: This process is extraordinarily scientific. We've spent the last week - and the last two days we haven't got much sleep, because we've been going through the detailed science, based on thousands and thousands of peer-reviewed literature. We've gone into the science in extraordinary detail, in extraordinary depth. And every single sentence has been scrutinised in great detail. And it's all based on peer-reviewed literature, and over 50,000 review comments that have been made, over the drafts of this report.
Shaun Ley: But it's not just the sceptics saying that - even somebody like Lord Stern, who did the report for the last government, into the economic consequences of climate change, has described it as a process of "filtering and haggling", in order, really, to get agreement between all these parties from all these different countries and the governments they represent.
Peter Stott: Well, you know the key point for me, coming into this week, was that the science would come through clear and strong. And it has, for sure. Because we have got this statement, very clearly expressed, that human influence on the climate system is clear, that the confidence is greater than 95% for the dominant role of human influence on climate. And the other point about this is that the governments have agreed to these statements. So the governments can't say "We don't agree to the science", because we have presented it to them, the scientists have been there, my colleagues and I, and we've shown them this evidence, and they've said "Yes, this evidence is right".
Shaun Ley: The other example that's raised on this is an interesting one - is this question of what's been described as a "pause" or "hiatus", where the degree of warming now appears to be at a slower rate than was originally thought. And there's been an argument about how much of that should appear in this report.
Peter Stott: We've always expected to have trends in shorter terms, that are less than the longer-term trend. In fact, in this assessment we've done a thorough assessment of this, and we've looked at what's happening in the ocean, we've looked at small effects from the fact the solar cycle has been as less this time than last, and so we've had this assessment that puts the recent 15 years into the longer-term context. In fact, in the last 15 years, we've presented evidence that the oceans have warmed, the snow and ice has melted, the sea level has continued to rise, and extremes have continued to become more intense and more frequent. And so, in fact it's evidence from the last 15 years that's added to the strength and the robustness of these conclusions about the dominant role of human influence on the warming that we've observed.
Shaun Ley: And for those who say "Look, that ought to inject a note of caution, that if there is this change over 15 years, it might not be borne out for a longer period, but right now we just don't know".
Peter Stott: We do know, and this report shows - as I say, we've got this very strong conclusion that human influence is clear, because we see it right across the climate system, including what we've seen in the last 15 years, including the fact that we've had record low Arctic sea ice extent, including the fact that rainfall patterns have changed, and more and more extreme weather is being observed. So it's very, very clear, what's coming out of this report.
Shaun Ley: We had some of the conclusions from the reports, back six years ago, being criticised. One most spectacular error that crept in was the suggestion that Himalayan glaciers would almost vanish by 2035. That was subsequently corrected. Given that experience, have you and your fellow authors been perhaps a bit more cautious this time, about what you put into the report?
Peter Stott: What has been happening this week in Stockholm is that we've had this really, really rigorous assessment - that's why we've had so little sleep the last two days, because we've been going through every single sentence line by line, and the scientists continually presenting the depth of the evidence. In fact, we have over a million words in this report and many, many diagrams, many, many assessments coming through. And so we've had this very, very rigorous level of scrutiny on the assessment.
Shaun Ley: Peter Stott, who helped to write the IPCC report.