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Australian Warming Overestimated By A Third

June 19, 2013

By Paul Homewood




A new study by Stockwell and Stewart, “Biases in the Australian high quality temperature network” has found that warming in Australia over the last century could have been overestimated by 31%.




Various reports identify global warming over the last century as around 0.7°C, but warming in Australia at around 0.9°C, suggesting Australia may be warming faster than the rest of the world. This study evaluates potential biases in the High Quality Network (HQN) compiled from 100 rural surface temperature series from 1910 due to: (1) homogeneity adjustments used to correct for changes in location and instrumentation, and (2) the discrimination of urban and rural sites. The approach was to compare the HQN with a new network compiled from raw data using the minimal adjustments necessary to produce contiguous series, called the Minimal Adjustment Network (MAN). The average temperature trend of the MAN stations was 31% lower than the HQN, and by a number of measures, the trend of the Australian MAN is consistent with the global trend. This suggests that biases from these sources have exaggerated apparent Australian warming. Additional problems with the HQN include failure of homogenization procedures to properly identify errors, individual sites adjusted more than the magnitude of putative warming last century, and some sites of such poor quality they should not be used, especially under a “High Quality” banner.


Which all raises the question, how reliable are temperatures from other parts of the world?

  1. Joe Public permalink
    June 19, 2013 7:11 pm

    “Biases in the Australian high quality temperature network”

    An oxymoron from down-under.

  2. Ian permalink
    June 21, 2013 11:36 pm

    The HQN has now been replaced by ACORN. I ran the data for Bourke (Jan 39) comparing the raw data and the new improved ACORN ‘adjustments’.
    I need say no more. The blatant ‘dumbing down’ of the higher temps is obvious.
    Bourke 1939 Jan raw Jan ACORN
    1st 38.9 38.4
    2nd 40 39.1
    3rd 42.2 41.9
    4th 38.1 37.9
    5th 38.9 38.4
    6th 41.7 41.5
    7th 41.7 41.5
    8th 43.4 43
    9th 46.1 45.7
    10th 48.3 47.9
    11th 47.2 46.8
    12th 46.2 45.8
    13th 45.7 45.3
    14th 46.1 45.7
    15th 47.2 46.8
    16th 46.7 46.3
    17th 40 39.1
    18th 40.1 39.1
    19th 40 39.1
    20th 41.9 41.7
    21st 42.5 42.1
    22nd 44.2 43.8
    23rd 36.7 36.5
    24th 40.3 39.2
    25th 36.6 36.5
    26th 29.4 29.5
    27th 29.3 29.4
    28th 28.8 28.9
    29th 30.6 30.5
    30th 35.6 35.4
    31st 38.6 38.3
    Highest daily 48.3 47.9
    Lowest daily 28.8 28.9
    Monthly mean 40.4 40.03548387

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