Select Committee on Science and Technology Minutes of Evidence

Examination of Witnesses (Questions 63 - 79)



Dr Turner

  63. Good afternoon and welcome, Professor Bowen, Professor O'Neill and Dr Shackley. This Committee's inquiry, as you know, is concerned with the field of scientific advice to Government. This Committee is not trying to resolve all the outstanding questions on climate change, causes, models, etc. None the less we are concerned with the quality of advice on those issues which goes to Government and Government's response to that advice. That is the context in which this inquiry is set. Could I begin, gentlemen, by asking you each to introduce yourselves and explain briefly how you are involved in the study of climate change. Can you mention in passing whether any of you work with the Hadley Centre or the IPCC and have any of you contributed to the peer review process which precedes the publication of IPCC reports? Incidentally, given that you do not necessarily all come from the same viewpoint, it is probably best if we make the questions fairly general unless someone wants to ask any one of you individually, so that you all feel free to contribute.
  (Professor O'Neill) I am Alan O'Neill. I am the Director of the Centre for Global Atmospheric Modelling at the University of Reading. My involvement in climate research is that I am a climate modeller, I use complex models of the climate system to check out the models, how they perform, how they behave. I am not involved in the longer term predictions associated with increasing greenhouse gases. I used to work for the Hadley Centre; I no longer do that. I have not been involved in the peer review process for IPCC.
  (Professor Bowen) I am David Bowen. I am Professor of Quaternary Geology in Cardiff University. My research interest over the last nearly 40 years has been with changes in the climate system on long timescales, glacials and interglacials, but recently I have been looking at changes on millennial timescales; hence my interest in giving evidence today. I have nature conservation interests. I was a member of the Nature Conservancy Council, I was a founder member of the Joint Nature Conservation Committee, and I have been Deputy Chairman of the Countryside Council for Wales for the last ten years. I have no connection with IPCC. I have no connection with the Hadley Centre and no connection with the peer review process. I am totally independent.
  (Dr Shackley) I am a social scientist and I work at UMIST. I am also one of the research programme managers of the new National Tyndall Centre for Climate Change Research within the new national centre. My involvement in this is that I have studied the process by which Government gets and assesses scientific advice on climate change through working at the Hadley Centre for a few months and talking to a lot of scientists and policy makers involved in this both within the United Kingdom and internationally. I have attended a number of IPCC meetings, not to be a scientist assessing the reports but to look at how the scientists themselves go about the assessment process and to look at how we can assess how rigorous that process is.

  64. Can I ask you, in turn, to state whether you think your views on climate change accord with the general tenor of the IPCC reports, or do you hold dissenting views?
  (Professor O'Neill) I generally accord with the IPCC reports. I recognise that there are uncertainties in climate predictions but nevertheless I subscribe to the weight of evidence that has been advanced in IPCC.
  (Professor Bowen) I would rather place more emphasis on uncertainty in the climate system. I would certainly like to see them take into consideration what is now definitively known about how the climate system changed in the past. In the 1996 report, for example, only three per cent of that report was devoted to past changes in climate.
  (Dr Shackley) I think there is a difference between the policy makers' summary of the IPCC and the full report and within the full report there is a whole wealth of viewpoints and uncertainties that do not always find themselves in the policy makers' summary. In terms of the full report I think that does represent the broad range of opinion within the community.

  65. Again, I have to ask you each individually: have you ever been asked for advice on climate change by the Government? How was your advice treated if it was sought? Conversely, have you ever offered the Government advice and, if so, how was that treated?
  (Professor O'Neill) I have been involved in giving Government advice on an issue related mostly to climate change or global change, and that was on ozone depletion, and a panel was created, the Stratospheric Ozone Review Group, which gave advice to Government through DETR. That advice was well received and evidently played a part in the Government's position vis-a-vis phasing out the chemicals that damage the ozone layer. I have not offered unsolicited advice to the Government.
  (Professor Bowen) Only through the agencies of non-governmental departmental bodies such as NCC and JNCC and latterly the Countryside Council for Wales. My advice on all of these occasions has been much the same, simply to state the level of uncertainty, not to take precipitate action without good cause, to understand that flood plains flood and coastal plains flood.
  (Dr Shackley) As a social scientist I have not been asked for advice on natural science. In terms of the social science aspects of climate change these are increasingly important issues. The Government's advisory system is less well developed than it is in the natural science area that the Hadley Centre provides and I think there is a need for better channels and different sorts of channels than they have established in the natural science area.

Dr Kumar

  66. Professor O'Neill, I want to explore the mathematical modelling of climate change models and you seem to be the expert on this from what you have just said to us. How good are these mathematical models and what are the limitations of these models? Do we have a grid big enough to predict this, given that there are so many variables and these are dynamic variables, patently? I wonder if you could tell us the limits and the uncertainties in your mathematical modelling work.
  (Professor O'Neill) This is a long story and I will have to keep it brief. The system we are dealing with is a highly complex coupled system as we say, so there are many interacting components: atmosphere, ocean, land, biosphere. In the last 30 years or so we have made very considerable advances in the development of the climate models to represent basic climate variability. That has been aided by the enhancement of computer technology and also by the availability of comprehensive satellite data which we can test our models against. A nutshell statement would be that the models now show very good abilities in predicting basic elements of the variability of the climate system. However, we recognise also that there are limitations in models. We know to a good approximation the physical laws that govern many of the important processes but when we try to solve those laws we cannot do it by hand; we have to use a computer, which means that we have to approximate the equations. Because the system is so complex—it involves a range of time and space scales—we inevitably make approximations in that representation on the grid. That is part of the reason we have uncertainties in the system. For example, a comparable case would be how do we represent properly clouds in a climate system? That is pretty obvious, that clouds would be quite important in deciding how the climate is going to behave. In summary—and you can press me further on the detail—is that one bears in mind two things, that the climate models that we are using are based on basic physical laws that are tested day after day in weather forecasting. They are also evaluated on longer timescales against global data and there is a great community of people out there who do that job. There are some weaknesses in the models. I have alluded to clouds already. We also have to represent more accurately than we do the role of the oceans. There are considerable uncertainties remaining in the way land surface processes, ocean processes, biological processes, impact on climate change. There is a feedback which we need to represent.

  67. That tells me how you have set up the equation and the difficulties of it but how good are your models in predicting? Do you get it right seven out of ten times, or nine out of ten times, or do you get it right absolutely?
  (Professor O'Neill) When we say do we get it right, we have to think about how we evaluate the models. We are dealing with a system which in many respects has chaotic elements embedded in elements that are more predictable. When we test out our models we are looking at past data and we see to what extent the models capture the basic processes, the evolution, the differences, say, in one hemisphere from another. We are looking very closely at phenomena such as the Indian monsoon, the El Niño, phenomena like that, and those are the ways in which we evaluate our models. When it comes to forecasting we have to take into account that there is inherent uncertainty and unpredictability in the system, or some elements of it, and therefore evaluating the model is a bit of a tricky process because if the model does not exactly perform compared with, say, how the atmosphere evolves in a particular time, it does not mean the model is wrong. That can be just to do with the system being so complex with some unpredictable elements. That is not the same when it comes to global climate change, that is to say, the climate change brought about by man's emissions from the burning of fossil fuels. That is not to say that the models then are not capable of being used for that purpose. In fact, quite recently they have been tested quite carefully against the recent temperature record when one puts into the models the greenhouse gases, changes in solar variability, aerosols, and compared to the global temperature, and a very considerable degree of success has been achieved in doing that. It is a matter of timescales and also of exactly what you are looking at.

Dr Turner

  68. Professor Bowen, do you have any observations about that? I am looking at this piece of evidence that you have supplied us with, showing that we have only this year reached temperatures of the Neolithic period.
  (Professor Bowen) Not quite.

  69. We seem to have got there in the late summer or early autumn which was the peak, and showed variations in solar radiation which have similar patterns.
  (Professor Bowen) First of all I could say that anybody studying natural systems must at the end of the day seek to model their systems and model them mathematically. The existing climate models have improved enormously over the last five years but they are still deficient in the sense that a model cannot incorporate all aspects of reality. My colleague just referred to the lack of cloud data. I do not think we are going to have this cloud data for another three years when CLOUDSAT goes up. This will be a satellite sent up specifically for reporting cloud cover characteristics, something we have not had before, although some of the NASA satellites that went up in the late seventies had radiometers on board and did produce a certain amount of information. As far as that diagram is concerned, yes, the temperature reconstruction is very close to IPCC. It is Jim Hansen's reconstruction and Jim Hansen is the man who coined the term "global warming" when he addressed Congress in 1987, and it shows very clearly the band of climate variability that was enjoyed (in so far as we can determine that from fossil evidence) during the Neolithic period about 6,000 years ago, and also during the last interglacial 125,000 years ago. The current climate has not reached that band of variability yet, yet the boundary conditions, the seaways, the ocean passages, the mountain systems, are much the same now as they were 125,000 years ago. If one is looking for a perfect analogue for the earth in recent geological time one needs to go back to 400,000 years, and that is the time when the orbital parameters of the earth were the same as they are today, and that interglacial was warmer than at present. It was natural warmth. The sea level was higher. Towards the end of the interglacial the sea level was ten metres above present, but the difference between this interglacial and that interglacial is that, whereas this has only been running 11,500 years, that lasted 60,000 years and I suspect that the longer this interglacial lasts the higher sea level will dribble up naturally, quite apart from any human forces that will be added to that, and that is the realm of uncertainty.

Dr Kumar

  70. I want to follow on, Dr Shackley, if you can comment as policy maker to ask how well can people in your field appreciate the limits of mathematical modelling? Do they appreciate that there are limits which are highlighted by Professor Bowen and how do you view it?
  (Dr Shackley) It is an interesting question because one of the problems in the past has been that people using data from climate models perceived that it was more certain than it actually is when you are doing, say, studies of the impacts of climate change on, say, flooding or upon agriculture. I think there has been quite a lot of learning that has now happened by those scientists talking to the climate modellers and there is better understanding now that these are scenarios, they are not predictions. There is a wide range of possibilities because of uncertainty, not only in the science but also uncertainty in how much future emissions of greenhouse gases will be, which is determined by essentially economic and policy decisions.

  71. Do you think in the past that policy makers relied too much on mathematical modelling in assessing climate change?
  (Dr Shackley) There is always a temptation to resort to a mathematical model because it appears to be something very objective, very rigorous, but the evidence we have heard already suggests that validating these models is very complex. We can probably never validate them to 100 per cent. There is always going to be residual uncertainty. One consequence of that is that we need to support a plurality of methods in looking at issues like climate change. We should not just put our trust in one particular method. Because of the uncertainty, we should perhaps foster a number of competing ways of looking at the same issue, if they are of good enough scientific quality.

  72. What are they?
  (Dr Shackley) There is a range of different kinds of climate models that can be used to assess climate change. The large, complex, coupled models are only one of a family of models. You could make the argument that we have put all the research money into supporting the big, complex models, whereas we could have been supporting for far less money some of the simpler models that could provide equally useful outputs for answering particular questions.

Dr Turner

  73. Given that practically the only response the Government has to climate change is to try and reduce CO2 output, given that Professor Bowen has eloquently explained how climate change is happening without any human activity, would anyone like to comment on the effectiveness of Kyoto targets in making any actual impact on climate change, even assuming that we manage to achieve them?
  (Professor O'Neill) Certainly it is the case that climate has changed greatly in the past quite naturally, before man walked the surface of the earth. There is no question about that. We see that in a number of records. What we are facing now is rapidity of climate change. The evidence is that that rapid climate change on a timescale of 100 years has been brought about by increases in the loading of greenhouse gases in the atmosphere. What we know also is that, even if we take considerable measures to cut or reduce the amount of greenhouse gas that we are emitting over the next 20/25 years, it takes such a long time for the gases to be expunged from the atmosphere or to be reduced to their natural levels that we are going to be committed to a measure of climate change increased by the increase in greenhouse gases. I can give you a whole host of scenarios with different outcomes according to the mathematical models, but the longer we delay the process the more we are committed to longer term climate change, if the mathematical models are to be believed, which I believe they are in this context.
  (Professor Bowen) My feeling is that Kyoto has now passed. If I may refer to Jim Hansen, he published a paper in August. There has been a supplementary open letter and quoting the CO2 forcing for 2050, a forcing of about three watts per square metre is involved. He has suggested that that could be cut down to one watt per square metre if carbon dioxide is kept more or less at the present levels and we attack the other greenhouse gases, methane in particular. The rate of methane increase has been decreasing in recent years and in particular if we attack particulate matter, exhaust fumes and, coming from India above all places, particulate soot matter—it has formed a deep, optical layer over the Indian Ocean that is influencing the greenhouse effect—that is one possible solution out of it.
  (Dr Shackley) This is partly an issue of timescale. What Jim Hansen says might be true for 2050 but the continuing emission of carbon will eventually result in a much higher rate of global warming. I think it is only valid on a relatively short timescale. On Kyoto, the key thing is that the 5.2 per cent reduction in greenhouse gas emissions from industrialised countries makes a very insignificant effect upon the climate, but it is only a first step and the Kyoto protocol was always only ever seen as being a first step in a long term process of cutting emissions far more than 5.2 per cent.

  Dr Turner: The US has not even ratified that.

Dr Williams

  74. Dr Shackley, you are an expert on scientific advice to government. On climate change, where is the Government getting most of its advice?
  (Dr Shackley) It is undeniably from the Hadley Centre.

  75. Is that 50 per cent, 80 per cent or 90 per cent?
  (Dr Shackley) I would say 90 per cent. Within the Hadley Centre there is a very strong connection with the IPCC process. The Hadley provides access to the government to a much wider range of international scientists. Also, Hadley places contracts with a number of other university departments around the United Kingdom. Again, it is not just Hadley; it also extends to a much wider community.

  76. The Hadley Centre is completely funded by government, is it not?
  (Dr Shackley) I believe it is.

  77. I noticed in your submission to us you said that there is a close and cooperative relationship between officials at the Hadley Centre and those in relevant government departments. "We have evidence that frequent face-to-face and remote communications between government officials and Hadley Centre scientists has many benefits for the interpretation of scientific understanding and new knowledge. This kind of relationship between climate scientists and government officials is rarely found elsewhere in the world ...". There are very close relations between government and this particular scientific advisory committee. Most advisory committees take pride in their independence from government; yet here you are saying that, because this works so closely with the government, the government listens much more to its advice.
  (Dr Shackley) Perhaps one of the important differences is because you have the assessment of the intergovernmental panel on climate change, which is entirely separate from government. It is intergovernmental but there are so many different parties involved that no one party can influence it very much. That provides the sort of reassurance that this assessment is independent of any particular government or any particular scientific organisation. It is probably because it is connected to this international process that this close relationship functions rather well. If it was purely a national assessment, it could very easily go wrong in the way that you imply.

  78. This kind of close relationship could work here but in the case of BSE or GM foods, nuclear power or some other controversial issue, where there is international back-up, there will be big changes needed.
  (Dr Shackley) Yes.

  79. Where Professor Bowen and other people have dissident views, do you feel that the mechanisms we have are so heavily dependent on Hadley that people have slightly different views, as happened with BSE, or is it the case, as with GM foods, they are out there doing their own thing, getting published but not getting noticed or considered by government?
  (Professor Bowen) Yes. I do not believe people talk enough to each other. Different groups of different persuasions simply do not get together. For example, ideally you should have a solar physicist here today who would have told you that the climate models underestimate the amount of solar forcing by a factor of three. A moment ago I talked about watts per square metre. It does not mean much to people but three watts per metre squared is three Christmas tree light bulbs put on every square metre of the earth's surface; yet we now know that solar radiance has increased by 2.8 watts per square metre from the Little Ice Age to the present. Given my own particular persuasion, it seems to me that we simply do not talk to people. We should be talking to oceanographers and modellers.

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