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For some years I have documented how the Australian Bureau of Meteorology remodel historical temperature data in the creation of the ACORN-SAT dataset, so it better fits the theory of human-caused global warming.   This winter I have discovered that the Bureau are now placing limits on how cold a temperature can actually be recorded in the ADAM database.

Not far from the peak of Australia’s Mountain Kosciusko, temperatures have been recorded at the Thredbo Top weather station (number 71032) since January 1966. On six separate days in 1968 temperatures dropped to minus 10 or below. On 23rd June 1968 temperatures dropped to minus 11.6. On 28th, 29th and 30th July of that year (1968) temperatures of -10.3, -10.6 and -10.1 were recorded.

During June and July of this year (2017) temperatures may have dropped this low over successive days, but we will never know.

At the beginning of this winter there was a limit placed on how cold a temperature measurement from this (and many other locations) could potentially be recorded. Any temperature measuring less than -10.0 was potentially rounded-up to -10.0, or replaced with a blank. For example, I saw the temperature of -10.4 measured by the Thredbo Top weather station, and then recorded as a blank in the CDO dataset on Sunday 16th July.

The Bureau initially acknowledged it had put these limits in place by way of emails to journalist Graham Lloyd and Griffith businessman Paul Salvestrin. Then it changed its story, claiming in a letter to Minister Josh Frydenberg: equipment failure. During the last week of July, Minister Josh Frydenberg ordered the equipment ‘fixed’. On 2nd August, a minimum temperature of -10.9 was recorded at this Thredbo Top station… as explained by Graham Lloyd in The Australian.

In fact, I have it on good advice that the Minister was told on, or about, 5th July that the ‘smart card reader’ installed into the Thredbo Top weather station limited the potential for low temperature recordings – yet no action was taken for at least three weeks.

On Wednesday 2nd August 2017, the same day that the Thredbo Top weather station was recording a very low minus 10.9, and as some farmers tallied up the exceptionally large number of frosts through July, the Bureau announced that July 2017 was the hottest on record.

Jennifer Marohasy BSc PhD
5th August 2017


My latest scientific publications, including on rainfall forecasting, are listed at the Climate Modelling Laboratory website.

I wrote the following two statements down on a scrap of paper when I was an undergraduate at the University of Queensland in the early 1980s.  They seemed to resonate more with me as each year passes:

1. Belief in the truth of a theory is inversely proportional to the precision of the science.

2. The creativity of a scientist is directly proportional to how much [s]he knows, and inversely proportional to how much [s]he believes.


For many years this website operated as a weblog, rapidly building a regular readership of several thousand.   Since 2007 the entire website has been archived by the National Library of Australia, annually, each February.


I moved to Noosa, in southeastern Queensland, a few years ago. In 2015, I established the Climate Modelling Laboratory to progress my work with John Abbot developing a technique for monthly rainfall forecasting using artificial neural networks: a form of artificial intelligence/machine learning/big data analytics – finding patterns, building models, projecting foreward, measuring the model’s skill at forecasting.

As well as interrogating large datasets, I enjoy swimming in the ocean, yoga, meditation and the occasional walk in the rain. My heros include William of Ockham, Thomas Huxley, Clement Wragge and Emile du Chatelet.

Jen cropped 70


For a list of my papers on rainfall forecasting and temperature reconstructions click here; a more comprehensive list of scientific publications is click here.  Over recent years I have been published in: Atmospheric Research, Advances in Atmospheric Research, Wetlands Ecology and Management, Human and Ecological Risk Assessment, Public Law Review and  Environmental Law and Management.

I was published every fortnight for about 10 years by The Land newspaper, Fairfax Media Ltd (April 2004 – November 2014).  I resigned as columnist, and also stopped regularly blogging, to concentrate more on my scientific research.

The skill of our forecasts can be measured in terms of root mean square errors (RMSE) and mean absolute error (MAE) relative to observed rainfall.  This means that our forecasts could be easily compared in a rigorous and quantitative way against the forecasts from general circulation models including the Bureau’s POAMA.  However, so far, the Bureau has resisted any comparisons being made, as I detailed in a letter to Simon Birmingham in August 2014, which can be downloaded here.  The skill of our rainfall forecasts is affected by the quality of the temperature series inputted as part of multidimensional arrays, which is why I have become somewhat vocal about the often ad hoc process of homogenization undertaken to temperature series by the Bureau.

I am also a senior fellow at the Institute of Public Affairs, with this work funded by the philanthropic B. Macfie Family Foundation.

For many years I have advocated the restoration of the Murray River’s estuary, and maintain The Myth and the Murray website.


On Line Opinion, Australia’s e-journal of social and political debate, published me from 2003 to 2017, with links to these articles here. I recently started writing for The Spectator, with my author page here.

I recently edited, and contributed chapters to, a 400-page book published by the Institute of Public Affairs – ‘Climate Change: The Facts 2017’. The first print-run was sold-out within 10 days, and the second print-run sold-out on orders before it was delivered. I will be advising soon, when and how more paperback copies will be available – with distribution rights in Australia, the UK and USA currently being negotiated. In the meantime the book can be downloaded from Amazon’s electronically: more information by clicking here.

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