Computer model is not evidence

NZ Herald crest

Letter sent to the Herald on 7 Jan, 2011
quill pen

Dear Sir,

It has come to my attention that you published a (further) letter from a Dr Doug Campbell, again challenging Professor Chris de Freitas’ recent article about the science of global warming. Dr Campbell said: “The facts support anthropogenic global warming with a doubling of atmospheric carbon dioxide resulting in warming of between 2 °C and 4.5 °C.”

I wish to point out that, as a matter of fact, that is not a fact.

Dr de Freitas was talking about an expected temperature increase from carbon dioxide alone of about 1 °C, and he mentioned that was, “by itself, relatively small” and “not controversial.”

Dr Campbell, if he disagrees with that, should cite his authority for doing so. The only source of temperature increases greater than one degree is various computer climate models. These models give different results on each run.

It is vital to recognise that the model results are not “facts” or “evidence”, nor should they be in the least persuasive of future climatic conditions. The IPCC themselves forbid the use of terms like “forecast” or “prediction”, in favour of “scenario”, “projection” or, more tellingly, “storyline”. The IPCC definitions are set out here.

Dr Campbell overlooked the fact that Dr de Freitas carefully described the carbon dioxide-induced temperature rise separately from any increase that might follow (called feedback). Because the only source of a temperature increase from feedback is these untested models (which, by definition, make no predictions), it is controversial. Thus it is improper for Dr Campbell to present those “storylines” as a scientifically reasonable “result” by using the words “the facts support”.

Research is under way now by Roy Spencer and others to discover the reality, and the indications are that there is a significant negative feedback from increased cloud formation in the tropics. Research is still under way because results are inconclusive.

But for Dr Campbell to drive his bulldozer of illogic through those scientific results without offering opposing observations is the antithesis of science.

Yours, etc.,
Richard Treadgold

Climate Conversation Group

PS: To CCG readers – please let me know if you see this has been published. Thanks.

Views: 60

12 Thoughts on “Computer model is not evidence

  1. val majkus on 10/01/2011 at 12:45 pm said:

    David Stockwell on his blog Niche Modelling says ‘The issue with NZ and Nordic data that the raw temperature data for weather stations do not show the temperature increases indicated by the IPCC, raising the question of how the data have been adjusted.’
    if stations are introduced in warmer climates late in the century, the average will be biased to warmer temperatures.

    However, issues in New Zealand and the Fennoscandian region are also found in Australia, proving the point that the compiled data cannot be taken at face value, and the adjustments to get them into the form we usually see need to be comprehensively audited.

    You can read the article at the link and there’s also a link to WUWT re NZ data – and read David’s bio at his ‘about the author’ link on his blog

    It would certainly seem that the ‘comprehensive audit’ in respect to NIWA’s 7SS has not occurred

  2. Richard C (NZ) on 10/01/2011 at 1:39 pm said:

    This Dr Campbell?
    Dr Douglas Campbell

    * Auckland District Health Board (ADHB) >
    * Auckland DHB Anaesthesia


    BM 1988 Soton; FRCA 1994
    Full NZ Registration Date

    12 August 1999
    Vocational Scope


  3. val majkus on 10/01/2011 at 4:06 pm said:

    here’s a fascinating historical account though it’s limited to Australia
    el gordo at Dr Marohassy’s blog directed me and which other readers might be interested in

    the influence of climate on the first european

    I mention it here because models don’t have the ability to hindcast but it’s nice to know what the history was from the weather journals and other records

  4. val majkus on 10/01/2011 at 8:29 pm said:

    RichardC thanks for your concern; I’ve made a comment on Dr Marohassy’s blog about the floods steal precious topsoil link by Sheehan
    here’s the blog and comment
    and here’s a comment by el gordo at

    now the historical link posted by el gordo is fascinating (for temperature enthusiasists it starts on page 9 I think; search for Dawes)

    as to Toowoomba’s situation thank you for the thought; yes, our back yard flooded but with the help of my neighbour who is a police officer I cleared the storm water drains but Toowoomba has had its second torrential downpour within a week – there are reports of cars being swept away but no damage to life; but thanks so much for the concern

    By the way all the river which falls in Toowoomba flows into the Condamine which flows into the Murray basin

  5. It is ironic that when the Queensland rains started Ministers in Gillard’s Government still had AGW briefing (papers) warnings fresh in their minds.
    The incoming Government’s Strategic Brief for the Climate Change and Energy Efficiency portfolio, dated September 2010 stated:

    “Climate models project that reduced rainfall is likely over most of Australia in the future”.

    A lengthy sojourn talking with Australian news commentators and business decision-makers over the past month convinces me that apart from some looney academics, green dumies, labour professional poiliticians and ‘crats, few Australians believe in the AGW rubbish.

    Richard, your letter is good stuff and if it is not published go to the Press Council as a test case!

Leave a Reply

Your email address will not be published. Required fields are marked *

Post Navigation