Considering Uncertainty in Climate Science

Sir John Bedddington, provides the introduction to a summary of “The Science of Climate change” on  UK Business Department website. He states

            “The fact that uncertainty exists in climate science, as it does in other fields, does not negate the value of the evidence – and it is important to recognise that uncertainty may go in both (or a number of) directions.”

This may be true in a new field, but there is evidence that where the consensus is concerned, when assumptions have to be made, or choices made between different scientific conclusions, there has been a very strong bias towards the more alarmist conclusions. For instance,

  1. The emphasis on positive feedbacks;
  2. The over-statement of climate sensitivities;
  3. The promotion of the hockey stick as secondary verification of recent warming being largely due to anthropogenic factors.
  4. Further there has been a public relations failure to challenge unsound science, or wild predictions, or false confirmations.
  5. Neither have there been any consensus scientists standing up to emphasise that the model scenarios of future temperature changes are not forecasts

The consequence of recognising uncertainty means that an audit is required of the total picture. Each part of the science needs to be graded according to the certainties. Most certain is that a massive increase in greenhouse gases will, ceteris paribus, cause a rise in temperature. At the other extreme are predictions that within a generation the Arctic Ocean will be ice-free in summer, or the Himalayan glaciers will have vanished, or the Maldives will disappear beneath the waves. The rhetoric needs to be replaced by establishing the case on a scientific basis. It is not sufficient to say that there is uncertainty and move on as is nothing had happened. The presence of uncertainty severely weakens the claim that the science is established and settled. We should now see the consequences for policy.

Hattip to BishopHill

The Division of Labour & Climate Science Part 1

Bishop Hill displays to an excellent short video at TED by Matt Ridley, encapsulating the concepts of the division of labour and comparative advantage. One thing that Matt Ridley leaves out is the creative destructiveness of competition through supplanting the existing order. Specialisation leads to new products and processes. By implication, the established processes and products are overturned. (Joseph Schumpeter needs to be added to the list of Adam Smith and David Ricardo)

It is not just in the sphere of production that these concepts apply. It is also with empirical science, be it economics, medical research or climatology. With complex data and many facets to the subject, there is scope for division of labour into

–         Data collectors,

–         Data analysts & measurers,

–         Statisticians to validate the analysis,

–         Theoreticians to innovate or create new ideas.

–         Mathematicians, to provide tools for analysis.

–         Methodologists, to provide structures of meaning and assess the boundaries of science.

–         This is alongside the general sub-divisions of the subject, which may change over time.

–         Alongside greater specialists there is also scope for generalist assessors who get a total perspective of the corpus of knowledge, weighing up the status of competing ideas.

–         Academic competition (to gain status) leads to improvements, but can also lead to diversity in conclusions. It also tends to blunt the conclusions where data is ambiguous or fuzzy.

This makes things a bit messy. In economics there has ceased to be any dominant schools of thought or policy prescriptions. But in climatology we are lucky to have the IPCC, which divides the world into a small group of generalist experts (who agree their main conclusions) and the masses, who accept the wisdom handed down. A bit like the guild system, that kept England in the Dark Ages.

The Hockey Stick and Climate Science

Posted Yesterday to the discussion at Climate Audit on the topic of “The Team Defends Paleo-Phrenology”

It may help …. to understand the nature of the science. It relies on statistical techniques to establish results. These, crucially, depend for their validity on the elimination of bias. If a researcher has faulty data, then the results are undermined. If the researcher is selective in the data, then the results are undermined. It outliers are not eliminated then the results are undermined. This all means that where there is extremely complex data, and problems of measurement, it is extremely difficult to establish conclusions that cannot be overturned. This is both true of economics and of paleoclimate.

I would contend that climate scientists, as a junior scientists, need to learn from other disciplines.
– From accountancy, about sense-checking the data (see link below)
– From research into new drugs, about the necessity for more technicians to collect and collate data, and to experiance dead-ends.
– From law, to distinguish between levels of evidence and distinguish baseless rhetoric from cogent arguement
– Most of all from statistical theory, where you will find you results will have no validity unless you take active steps to eliminate bias. Even then, with complex data, your results may still be later undermined, despite passing a battery of tests.

For all of these reasons, we should accept that the results of research are tentative. We should recognise the limits of our knowledge. In recognising the boundaries, and establishing procedures to quickly identify error, paleoclimate may be able to move forward.


The whole hockey stick issue, brought to a head with the Tamino posting, shows the problem of bias. To obtain a temperature reconstruction requires using data that usually gives a very weak signal indeed. Therefore any data needs to be carefully collected and every conceivable bias removed. It is only by eliminating bias that the statistical analysis can begin. In many cases there will be no significant results. Much painstaking work will achieve a dead end. And there is the rub. Careers are not made by failing to get a result. In this arena phenomenal fame and prestige can come to those who produce results that fortify the consensus. And there is plenty of recognition to those with supporting roles as well.

The original MBH98 may never have emerged in a more muted form if an expert reviewer had asked how such a novel result could be reconciled with the existing view that there was a medieval warm period. Hence my point about sense-checking in the previous blog posting. Similarly the comment that the 20th century warming was unprecedented should be answered with how do you know that? Read the Hockey Stick Illusion and you will find that the claim lacks scientific validity.  

If climate science it to mature it needs more painstaking data collection and analysis. As a science, it needs to find the current boundaries and limits of our current knowledge.

For those who believe that the Hockey Stick Team still have something worthwhile to say, should start with Steve McIntyres repost of “Tamino and the Magic Flute“. Compare that with Tamino’s posting “The Montford Delusion”.

Look at

1. Who gives the fullest answers?

2. Which side evades the points, or attempts sleight of hand?

3. How are contrary or neutral points treated. Clue – look at how Judith Curry (who is trying to remain neutral) is treated. Further, look at how contrary opinions are treated.

4. Finally who are the real deniers in all of this?

Climate Change – New Scientist puts smears before science

The latest issue of the New Scientist features a series of articles on climate change deniers (see below). The second – “Living in denial: When a sceptic isn’t a scepticcompares “climate” deniers with deniers of the holocaust, 9/11, Aids, vaccine, evolution and the harmful effects of tobacco. It is this last that I have just posted a fuller analysis.

Alternatively consider these two arguments.

1. The proposition that smoking is harmful to health was initially based on a study of 34,000 British Doctors. The study itself was “heralded a new type of scientific research”. The results have been replicated, refined and further issues identified. To deny that smoking is harmful  to health is equivalent to denying a simple fact. By implication you are going against science, so must either have an ulterior motive or be a crank.

2. The proposition that the climate system will be changed catastrophically is agreed upon by a very large number of scientists, as a result of a huge numbers published papers, using similar empirical methods to that used in medical research. So those who oppose the AGW consensus, must be equivalent to those who oppose the medical consensus on smoking.

This is bad science seeking to piggy-back on the reputation of good science. If the results of climate change science were so clearly unambiguous, then the counter-arguments would be easily dismissed by clear presentation of that science. But there are deep flaws in the science, so smears are necessary.  


 Hatip wattsupwiththat From their article is the following:-

Here’s links to all the New Scientist articles on “denial”. They did include one article from Michael Fitzpatrick that is a 
feeble attempt at balance,but even it too strays into the ugly territory of comparing climate skeptics with AIDS deniers.

Big Tobacco and Climate Change Deniers

NB – an article I wrote last year – slightly updated and posted here for the first time.

See also following post; “Climate Change – New Scientist puts smears before science

A comment thrown at the “skeptics” or “deniers” is that they use a similar tactics to Big Tobacco in the fight against the harm that tobacco does to health (1). That is they issue false data and research to throw policy makers off the scent. Further, it is claimed they use similar arguments as Big Tobacco in opposing the climate change science.

This is a misleading analogy in four areas.

  1. On the tobacco issue, the first major study on the link between lung cancer, heart attacks and smoking was ground-breaking research based on questionnaires returned from over 34000 British doctors. This study was continued for 50 years, reinforcing the original findings. Further, independent studies not only corroborated these initial findings, but enhanced the detail. Much of the initial temperature data for AGW studies were more ambiguous, reliant on a loose correspondence between the rise in greenhouse gases and average global temperatures. Moreover, data is often not properly archived, whether early studies (eg. Jones et al 1990), or later ones (e.g. Kaufman et al 2009)
  2. On tobacco issues, it is possible to have a control group. That is, you can follow the health of a large representative group of people who smoke, and follow a similar cross-section of society group who do not smoke. The control for anthropogenic warming is temperature histories. That is, if recent warming is unprecedented in a thousand years or more, it can only be explained by anthropogenic factors. If however, the 20th century warming was no bigger than similar warmings at 1,000 and 2,000 years ago, then the anthropogenic element is likely to be small. Not only has the two most influential past temperatures reconstructions showing the former case have been rebutted (MBH 1998 – see especially Mcintyre 2008b and Briffa 2000), but also the total temperature reconstructions that show the medieval period was at least as warm as currently outnumber 7 to 1 that show the it was cooler.
  3. The selection criteria on medical research is published, along with sample sizes and the statistical tests on the results. Therefore, statisticians can check the results. The statistician and climate skeptic Steve McIntyre has his work cut out to get similar information from the climate scientists. See for instance the battle for the Briffa’s Yamal data or the Jones data that underpins the temperature reconstructions of the IPCC.
  4. In general, the vast majority of medical research published in peer-reviewed journals is later refuted, or at least undermined. It is often of poor quality. Therefore in medicine, a peer reviewed research is but the first stage in getting an idea established. It needs to be replicated by other studies and cross-checked. Climate science is summarized by the UN IPCC is a form that reinforces a partisan viewpoint, rather than drawing conclusions through comparing and contrasting. For instance Steve McIntyre has posted his reviewer’s objections to the analysis of past temperatures in the 2007 assessment report, and the rejections. In the light of his subsequent exposure if the Yamal paper, these turn out to be entirely valid.


For the analogy to be upheld, climatologists need to show that their research programme is comparable in robustness and replication as the medical research was in the 1970s. My contention is that it falls far short. By implication, those who are either skeptical of the robustness of the results, or who deny completely the validity of the research programme, have much surer foundations for their doubts, even before presenting any research to the contrary.

1.See, for instance, Thomas Fuller (who, seeks communication between the opposing sides) at

The fact that for many of the staunchest activists any bending is tantamount to surrender makes compromise difficult. They take their lessons from what happened with Big Tobacco, where the strategy of introducing doubt into the science allowed them to postpone accountability for their actions. They must take a blood oath or something to never admit error and never back down. I don’t admire them for that–they should trust the power of the truth.

Medical papers from sloppy analysis

(Hattip Anthony Watts blog

The argument of big tobacco and anti-AGW is backed by a BBC Newsnight on Phillip Morris funding one of the 1st anti-AGW groups.