Discussion of the ‘Hottest Year on Record’ in Australia

Written by Albert Parker, Clifford D Ollier

New peer-reviewed study of raw temperature data for Australia proves no warming trend exists in the actual records – only in the adjustments. Evidence proves that published records by Australian Bureau of Meteorology are intentionally and artificially exaggerated with a subjective (probably political) bias.

Albert Parker of the School of Engineering and Physical Science, James Cook University, Townsville, Australia and Cliff Ollier of the School of Earth and Environment, The University of Western Australia show that Australian records since the end of the 1800s give no sign of warming or increased occurrence of extreme weather events.

The full paper may be accessed free at:


Abstract: The global temperature trends provided by the Australian Bureau of Meteorology are artificially exaggerated due to subjective and unidirectional adjustments of recorded values. The present paper aims to promote the use of the raw stations’ data corrected only for urban heat island formation.

The longer temperature records of Australia exhibit significant oscillations with a strong quasi-60 years’ signature of downward phases 1880 to 1910, 1940 to 1970 and 2000 to present, and upwards phases 1910 to 1940 and 1970 to 2000. A longer oscillation with downward phase until 1910 and an upwards phase afterwards is also detected.

The warming since 1910 occurred at a nearly constant rate. Over the full length of the long Australian records since the end of the 1800s, there is no sign of warming or increased occurrence of extreme events. The monthly highest and mean maximum temperatures do not exhibit any positive trend. The differences between monthly highest and lowest, or monthly mean maximum and mean minimum temperatures, are all reducing because of urban heat island formation.


Raw temperature data of historical stations not affected by large urban heat islands show temperatures have not warmed since the end of the 1800s (Boretti 2013, Parker 2013a, b, Watts 2013, JoNova 2014, Parker 2014a, b, Parker, Ollier 2015a, b, c, Parker 2016, Marohasy 2017, WAclimate 2017).

The list of the non-warming stations includes Alice Spring, Darwin, Cape Otway, Wilsons Promontory, Echuca, Horsham, Orbost, Gabo Island, Rutherglen, Newcastle, Bathurst, Burke, Amberley and Deniliquin and many others.

In the case of historical stations with large urban heat islands, as for example Melbourne, Sydney, Perth, Adelaide and Brisbane the minimum temperatures have warmed significantly more than the maximum temperatures. The warming vanishes moving to the country side, as for example moving from Melbourne to Ballarat or other unaffected locations of regional Victoria as shown by Parker (2013b).

Technicalities such as the installation of Stevenson screens and more recently the installation of automatic weather stations using thermistors rather than mercury or alcohol thermometers affect the temperature readings for the average. Thermistors are much more sensitive to temperature changes and suggest larger fluctuations. Stevenson screens shield thermometer from direct heat radiation and may affect the maximum temperatures.

Other factors affecting the temperature measurements include smaller urban heat island effect, change of land use, more localised effects linked to heat release and storage processes close to the thermometer location (such as the presence of an air conditioning unit, a car park, a glass tram stop or heavy traffic), and air motion due to buildings.

Changes of location of the measuring equipment as Town to Airport or simple relocation of the thermometer will also affect the measurements. The Australian Bureau of Meteorology (BOM) is well known for its continuous adjustments of the recorded values of temperatures to produce warming trends resembling those required to support the concept of global warming caused by anthropogenic carbon dioxide emission.

The pinnacle of these administrative corrections has been the definition of the latest Australian Climate Observations Reference Network – Surface Air Temperature (ACORN-SAT) data set. This exercise has permitted the BOM to magnify the warming trends by reducing the temperatures of the past and to magnify the frequency of extreme events by increasing the summer temperatures while reducing the winter temperatures.

The warming trend is computed from the time series of the average temperatures, the occurrence of extreme events is somehow linked to the time series of the difference between maximum and minimum temperatures. Reducing the temperatures of the past increases the warming, and increases the difference between maximum and minimum temperatures for same average temperature increases.

Extreme events are becoming more frequent. The engineered warming has been shown in peer review papers (Boretti 2013, Parker 2013a, b, Parker 2014a, b, Parker, Ollier 2015a, b, c, Parker 2016) and blogs. The subtler differential seasonal warming has been shown so far only in the blog (JoNova 2014) in which Ken Stewart compared the ACORN and the Australian Water Availability Project (AWAP) temperature data set to find that Australian summer maximums have been warmed by 200% with the ACORN data.

Parker (2014b) presents the raw temperature data measured in Alice Spring and the latest ACORN reconstruction. Alice Spring is not considered in the present analysis.

The time window end of the 1800s to present is actually covered not by one single station but by two stations, with a change of site from the Post Office to the Airport location. The significant overlapping in between the two records does not pose any issue in deriving a composite record as shown in Boretti (2013) and Parker (2014b).

The reconstructed ACORN and the raw measured minimum and maximum temperatures do not agree. The time window of the reconstructed data magnifies the warming. The reconstructed data also increase the warming by making lower the temperatures of the past. The measured values show no warming at all since 1888, and a much smaller warming of 0.46 and 1.1°C/century of minimum and maximum temperatures since 1910.

Legitimate homogenizations of the Alice Spring record are not easy, as there are no surrounding stations to average with. The supporting data of Parker (2014b) were downloaded from Australian Government Bureau of Meteorology (BOM 2014a, b). Climate Data Online (CDO) provides access to a range of statistics, recent weather observations and climate data from the Australian Data Archive for Meteorology (ADAM), a database which holds weather observations dating back to the mid- 1800s for some sites.

The climate change trends computed by the Bureau of Meteorology are based on selected subsets of data that have been changed many times in the recent years with raw temperature measurements mostly arbitrarily corrected or neglected. Analysis of the raw temperature data has always returned patterns completely different from those claimed by the BOM in their state-of-the-climate reports. Kenskingdom (2014) presents the mysterious correction for Rutherglen, a rare long rural temperature record where measurements had come from the same place since 1913.

Rutherglen was one of the temperature recording stations that was subject to large adjustments which turned a slight cooling trend into a strongly warming one. The official notes showed that the site did not move and was a continuous record. Retired scientists who worked at times at Rutherglen confirm the official thermometer had not moved. The original cooling trend of -0.35°C/century was transformed into a +1.73°C/century warming after homogenization justified by the BOM as the result of an unrecorded shift.

JoNova (2014) presents the result of the analysis performed by Ken Stewart of the adjustments used to create the all-new ACORN dataset compared with the other BOM dataset called AWAP. Since summer maxima are the ones used to generate the most headlines in Australia, the trend in average summer maximums has been tripled by adjustments.

Ken Stewart splits the data into months, and compares the trends in maxima in the AWAP and ACORN datasets, across the entire nation. Most of the adjustments happen to data from the hottest months of the year, October to March. Even though the measured maxima in February and March are possibly cooler now than they were in the early 1900s, they have been adjusted to show warming trends.

Adjustments grossly exaggerate monthly and seasonal warming. The supporting data was downloaded from Australian Government Bureau of Meteorology (BOM 2014b, c). Watts (2013) presents Australian summer (December to February) surface air temperatures over the satellite era. This time the source of information is not a BOM data set but the Remote Sensing Systems (RSS 2017) and University of Alabama in Huntsville (UAH) data base.

Microwave sounding unit temperature measurements have been obtained from the troposphere since 1979, when they were included within the National Oceanic and Atmospheric Administration (NOAA) weather satellites. Satellites measure radiances in various wavelength bands, which is then mathematically processed to obtain indirect inferences of temperature. Different groups analysed the satellite data. Among these groups are RSS and UAH. The Australian temperatures from the RSS and UAH groups show that there was nothing unusual about the 2012 summer.

The supporting data were downloaded from KNMI (2014). Parker, Ollier (2015b) asked the question which causes more warming, carbon dioxide or Bureau of Meteorology (BOM) adjustments? and concluded the warming of Australia is mostly an artefact of BOM adjustments. Another fundamental research question was which causes more summer heatwaves: carbon dioxide or Bureau of Meteorology (BOM) adjustments? The answer by Ken Stewart was that the heat waves of Australia are likewise mostly an artefact of BOM adjustments.

The present paper shows that the use of raw data provides a superior estimate of the actual warming trends than the unnaturally exaggerated global temperature trends provided by the Australian Bureau of Meteorology. This superior estimate shows the repeated claims that almost every year is the hottest year on record are not trustworthy. The warming in the world top net sequestering country for carbon dioxide, Australia (Parker, Ollier 2015d) is conclusively substantially overrated.

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