The Consensus about Climate Change and Extreme Weather.

  by Anthony Cox

Great scientists like Richard Feynman and Einstein both agreed that it didn’t matter how many people believed in a theory all it took to disprove a theory was one fact.

The supporters of man-made climate change or AGW rely very heavily on the idea that a majority or consensus of scientists support AGW and therefore it must be right.

Even US President Barack Obama has accepted the idea of a consensus and that it proves AGW. 

President Obama tweeted that: 
Ninety-seven percent of scientists agree: #climate change is real, man-made and dangerous. 
Obama based his tweet on the latest evidence for a consensus about AGW from a recent paper by a team which includes Australian academic John Cook who runs the pro-AGW blog site Skeptical Science.

In their paper Cook and his team categorised the authors of scientific papers into 7 groups with the first category:

Explicitly (stating) that humans are the primary cause of recent global warming

That is fairly unambiguous and represents the accepted definition of AGW: that humans are the main cause of climate change.

However when a number of other scientists checked Cook’s results they found that not 97% of the sample of approximately 12000 scientists were in category 1 but less than 1% and in fact more scientists believed category 6 which said:

Explicitly minimizes or rejects that humans are causing global warming

In addition none of Cook’s categories described AGW as dangerous as President Obama tweeted but that in itself shows how much the issue has been politicised.

The politicisation of AGW was further shown by the comments made by certain politicians about the recent bushfires in Australia and the dreadful Typhoon in the Philippines.

Despite the Intergovernmental Panel for Climate Change [IPCC] in its latest report, AR5, explicitly stating that there is no conclusive evidence to support a connection between AGW and extreme weather events like the bushfires or the Typhoon that has not stopped politicians like Adam Bandt and Christine Milne claiming such events as proof of AGW.

In fact according to a leading pro-AGW scientist, Professor Richard Muller from Berkeley a lack of extreme weather events may be a proof of AGW.

According to Muller in a warming world the poles warm up relative to other parts of the world and that decreases the temperature differences between parts of the Earth. Extreme weather depends on a strong temperature gradient and the energy that provides. If those energy gradients are decreasing then logically there should be less extreme events.

This is the problem now with AGW; it has become politicised and even ideologically driven. Not to mention driving a vast investment and expenditure by governments and corporations.

Whenever politics and money become involved scientific independence takes a back seat. I don’t think either Feynman or Einstein would approve of the consensus or politicisation of extreme weather disasters.

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  1. As lead author of the consensus paper discussed above, I can point out that Anthony Cox (from the highly politicised "Climate Sceptics Party") grossly misrepresents and distorts the results of our paper, published in the peer-reviewed scientific journal Environmental Research Letters.

    Cox achieves this by using the misleading technique of 'unrealistic expectations' - demanding unreasonable levels of scientific proof. The tobacco industry perfected this approach in the 1970s, demanding ever-more stringent levels of proof that smoking caused cancer in order to delay government regulation of their products. In this article, Cox claims less than 1% of climate papers endorse human-caused global warming. In order to do this, Cox uses a stringent and unreasonable definition of what constitutes endorsement of the consensus - and consequently ignores thousands of relevant papers. According to Cox, the following statements don't endorse the consensus that humans are causing global warming:

    “Global warming caused by green house gases emitted into the air is a result of the human activities.”
    “…emission reduction efforts alone are unlikely to stabilize greenhouse gas concentrations at levels low enough to prevent dangerous anthropogenic interference with the climate system.”
    “Accumulating evidence points to an anthropogenic 'fingerprint' on the global climate change that has occurred in the last century.”

    The technique of unrealistic expectations is one of several tactics employed by groups that deny a scientific consensus. Other tactics include cherry picking, fake experts and conspiracy theories. These techniques were used by the tobacco industry and right-wing ideologues to deny that smoking causes cancer. The very same techniques are now being used by the fossil fuel industry and ring-wing ideologues to deny that humans cause global warming.

    Our paper on scientific consensus is freely available at and a user-friendly explanation of our research is available at

    1. Good of you to turn up John.

      I didn't use any definition other than what you used in your paper. Would you care to present the number of abstracts which conform to your paper's first definition and your sixth definition? That should clear up the issue.
      As for "unrealistic expectations", my only expectation is that the facts be allowed to speak for themselves.

      And in stressing my membership of TCS thanks for proving my point about the politicisation of the science of AGW.

    2. Anthony, I'd say the unhappy Mr Cook has just completed the proverbial 'own goal'.

    3. Curious request. Why would you wish to compare the 1st definition of consensus "Endorse AGW and quantify it as more than 50%" with the 6th definition "Explicitly reject AGW"? They're apples and oranges. A more appropriate comparison is the 2nd definition "Explicitly endorse AGW" with the 6th definition "Explicitly reject AGW". What do we get when we make that comparison?

      934 papers explicitly endorse anthropogenic global warming (AGW)

      15 papers explicitly reject anthropogenic global warming (AGW)

      E.g., among papers that explicitly state a position on AGW, 98.4% endorse the consensus.

      Your unrealistic expectation is that a paper that states “Global warming caused by green house gases emitted into the air is a result of the human activities” does not endorse human-caused global warming.

    4. We are talking about this paper aren't we:

      The first 2 categories of Table 2 are:

      1) Explicit endorsement with quantification. Explicitly states that humans are the primary cause of recent global warming. The global warming during the 20th century is caused mainly by increasing greenhouse gas concentration especially since the late 1980s'.

      (2) Explicit endorsement without quantification. Explicitly states humans are causing global warming or refers to anthropogenic global warming/climate change as a known fact. Emissions of a broad range of greenhouse gases of varying lifetimes contribute to global climate change.

      Now I would think that category 1 is a more definitive support of AGW since it is based on quantification, which I gather to mean statistical proof whereas category 2 has explicit support without such proof.

      Strangely however category 6 is a stronger rejection of AGW then category 7 which is why I compared it with category 1 which appears to be the strongest support. Category 6 states:

      (6) Explicit rejection without quantification. Explicitly minimizes or rejects that humans are causing global warming'...the global temperature record provides little support for the catastrophic view of the greenhouse effect.

      Category 7:

      (7) Explicit rejection with quantification. Explicitly states that humans are causing less than half of global warming. The human contribution to the CO2 content in the atmosphere and the increase in temperature is negligible in comparison with other sources of carbon dioxide emission.

      Category 7 requires quantification it is true but that quantification still allows for AGW to cause 50% of global warming whereas category 6 rejects AGW 100%.

      The rest of the categories are also as interchangeable. The point is who and by what criteria was the allocation of the Abstracts into the respective categories made. There is an unavoidable element of subjectivity in the process of categorisation as was found in this analysis:

      The authors of this analysis also found the descriptions in the various categories unavoidably skew the results towards Cook’s thesis. This is not unbiased science and demonstrates the way a preconceived idea can prejudice a result.

      The point is made by these scientists whose papers were put into categories in Cook’s study and who strongly reject that categorisation:

      You would think the authors of the papers would know better than the people making the categorisations. How many more papers classified by Cook et al are at odds with their authors?

    5. Replication is the heart of the scientific method which is why we asked the authors of the papers to categorise their own papers. 1200 scientists rated their own papers, resulting in over 2000 papers being categorised by the papers' own authors. Among papers that were self-rated as stating a position on human-caused global warming, 97.2% endorsed the consensus.

      Compare this to the result from our method of abstract rating, with 97.1% consensus. As I said, replication is the heart of the scientific method. Our result also replicates earlier surveys of the climate science community - one in 2009 that found 97.4% consensus, one in 2010 that found between 97 to 98% consensus.

      Rather than link to a blog post that has 7 scientists categorising their own papers, I recommend reading our peer-reviewed paper which shows the results from 1200 scientists categorising their own papers:

    6. I agree John replication is the key to proving a theory. However what you are replicating is unclear.

      In your paper you define the consensus position as being:

      "That humans are causing global warming."

      That consensus position is defined in your categories by category 1 of Table 2 which I have already quoted. The rest of your categories reflect
      varying degrees of lessor support for AGW [categories 2 and 3], or indifference to AGW [categories 4a and 4b] or active opposition to AGW [categories 5 to 7]. Only the first 3 categories could be defined as giving support for AGW.

      However, on the basis of the categories 1-3, of the original 11944 Abstracts from papers on climate you selected you discarded 8048 papers or 67.4% because they had no position.

      Of the remaining 4014 papers or 32.6% of papers 3973 or 99%
      of the remaining abstracts fell into categories 2 and 3. Only 41 or 1%
      expressed support for YOUR definition of the consensus that:

      "Humans are causing global warming."

      That’s 1% not 97%.

      Now you say you had the authors of the papers rate their papers according to your criteria; you say:

      § "1200 scientists rated their own papers, resulting in over 2000 papers being categorised by the papers' own authors. Among papers that were self-rated as stating a position on human-caused global warming, 97.2% endorsed the consensus."

      The author’s self-rating is shown by Table 4 from your paper.
      In fact 2142 papers received self-ratings from 1189 authors. Your paper says of those 2142 self-ratings 1342 are described as Endorsing AGW. That is confirming the consensus position or category 1 of your 7 categories. The caption to Table 4 says:

      "Self-rated papers that endorse AGW have an average endorsement rating less than 4."

      But that would include categories 2 and 3 which are LESS than
      the consensus position. So the question remains exactly how many self-rated Abstracts actually conform to your own definition of the consensus as defined only in category 1.

      In addition, the self-referencing shows that 761 scientists have no position on AGW which as the caption to Table 4 says conforms
      to categories 4a and 4b of your categories which is 761/2142 X 100 = 35.52%. That is much less than your paper’s initial selection and discard of 67.4% of the 11,944 papers because the Abstract had no position on AGW.

      § Maybe the only scientists who responded to your invitation to self-rate were those who initially had a position on AGW. If so 35.52% of them changed their minds from being in categories 1-3 to being in
      categories 4a and 4b!

      Any way you look at this the % actually supporting the consensus, as defined in your paper, is less than the claimed 97%.


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