No Evidence of Greenhouse Warming for 67 Years!

The release of 2013 data by the BOM has provided me with plenty to work on.  Various commentators are busily alarming people by claiming that the hottest year on record is an indication that global warming due to the enhanced greenhouse effect is already impacting Australia.  What is most disappointing is that the BOM has done nothing to report the truth: that while Australia has definitely been warming, and breaking records, the data show no evidence of greenhouse warming.

One of the key indicators of warming uniquely associated with the enhanced greenhouse effect is night time temperatures (minima) increasing faster than daytime temperatures (maxima).  The difference between the two is called the Diurnal Temperature Range, or DTR.  So, decreasing DTR would be evidence of greenhouse warming.

Here is Australian DTR since 1947:dtr1947-2013

That’s dead flat or slightly rising for 67 years!

I couldn’t believe it either, and double checked.  There’s no mistake- DTR shows no evidence of greenhouse warming in Australia, with a flat trend for 67 years.

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2 Responses to “No Evidence of Greenhouse Warming for 67 Years!”

  1. wazsah Says:

    In 1997 Easterling et al put out the landmark paper on DTR
    Easterling, D.R. et al., 1997, “Maximum and minimum temperature trends for the globe”, Science, 277, 364-367.

    If you scroll down to the 3 maps, the lower of which shows DTR grid point trends – you see that GHCN data from Australia on balance would show a negative DTR trend of maybe 2° per 100 yrs.

    As you show the BoM ACORN SAT DTR change is neglible

    Here is an unpublished paper which looked at 64 stations over Eastern Australia showing the increasing closing of DTR with population.
    Previously unpublished paper by Hughes and Balling , “Eastern Australia temperature variations 1930-1992”
    rejected in review in the mid-1990’s.
    Still the best attempt to compile a rural temperature trend for Eastern Australia.
    Page 19 Fig showing trends in mean T increase and DTR decrease related to population

    IMHO the flat DTR trend in ACORN is an unintended side effect of the BoM warming adjustments and is a manifestation of the torturing of data to produce ACORN SAT.

  2. Ken Stewart Says:

    I agree. I’m enjoying the unintended consequences for Acorn, and UHI has to warm even small communities’ minima. Acorn station metadata talks about ‘anomalous warming of minima’ as a symptom of UHI e.g. at Laverton RAAF and Richmond (NSW), so they certainly know that decreasing DTR is not a unique indicator of greenhouse warming- but that’s still the claim.

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