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Australia – was hot and is hot. So what? This is not an unusual heatwave

Posted By Chris Gillham On January 15, 2013 @ 3:22 am In Global Warming | Comments Disabled

The media are in overdrive, making out that “the extreme heat is the new normal” in Australia. The Great Australian Heatwave of January 2013 didn’t push the mercury above 50C at any weather station in Australia, yet it’s been 50C (122F) and hotter in many inland towns across Australia over the past century. See how many are in the late 1800′s and early to mid 1900′s. You can’t blame those high records on man made global warming.  [feel free to post some old records of your own and the source reference we can check and we will update the map]

 Did CO2 cause extreme heat in the 1820′s?

In explorer Charles Sturt’s time it was so hot that thermometers exploded. Was this Australia’s hottest day all the way back in 1828? It was 122F or 53.9C! Naturally it is not a BOM-registered-record (the BOM did not exist then). Nonetheless, Charles Sturt was engaged to explore the nation and given careful instructions to take accurate readings of the climate. Yes, inadequate thermometer shading may have exaggerated the maximum by 1C, 2C, maybe even 3C, but at 50.9C it would still have been considerably hotter than anywhere in January 2013.

Even that long ago, thermometers were a tried and tested piece of equipment. They had been used for 200 years, and the Fahrenheit scale was nearly 100 years old. There weren’t too many people taking temperatures in Australia that day. What are the odds that Sturt happened to be at the absolute hottest spot in the continent? Perhaps it was pretty damn hot everywhere that day? We’ll never know. But that was not the only reading he took  of 50C+ temperatures. Other early explorers also found extreme heat, like Mitchell in 1845.

The largest longest heatwave that has turned up in historical records so far appears to be the one in January 1896 when temperatures raged above 40C across the country from West to East, getting so bad around Bourke that the government put on extra trains to allow people to escape. Panic stricken people fled for the coast and mountains as hundreds died.

The Australian BOM say this current pattern of extreme heat is “consistent with climate change”

This pattern of extreme heat is also consistent with Australia’s historical records set when human green house gas emissions were a fraction of what they are today.

With any record set in the modern era, you need to know two things. One is that The BOM’s raw data adjustments have increased the warming trends in the raw data by around 40%. The second is that when asked, Dr David Jones, Head of Climate Monitoring and Prediction, National Climate Centre, Bureau of Meteorology, stated untruthfully that the adjustments madea near zero impact on the all Australian temperature trends”. 

BOM Excuse for deleting some long held temperature records

The BOM state that to measure the temperature of the air accurately, it is important that the thermometer is shielded from direct sunlight but is still exposed to a good airflow. The standard screen used internationally to shelter instruments is a double-louvred wooden box, with the instruments 1.2 to 2.0 metres above ground level. This screen, known as ‘a Stevenson screen’, was designed by Thomas Stevenson (1818-1887), a British civil engineer and father of Robert Louis Stevenson. The use of a standard screen allows temperatures to be compared accurately with those measured in earlier years and at different places.

The Stevenson screen was first introduced to Australia in the 1880′s and was installed everywhere, with a few exceptions, by 1910. Prior to this date, thermometers were located in various types of shelter, and locations particularly by trained explorers and early landowners, post masters telegraph station attendants and the like who saw it as an important part of their duty. The Stevenson Screens were in fact designed to try to replicate the conditions in which they had been measuring temperature already in most cases. So unless it was clearly documented that the method prior to the installation of the Stevenson Screen was deficient, there would be no reason to disregard the earlier records from the BOM records.

However that is what BOM appears to have done, particularly when the high temperature records were long dated. It is strange that even the the Stevenson Screens were installed by 1910, it took the BOM until the early 2000′s to decide to axe some of Australia’s oldest temperature records.

But they cant be expunged from historical records which is where our team dug some up.

Also strangely, the BOM seems to have no problems with the many temperature stations which are sited in areas where there has been substantial urban and industrial growth which will impact more recent warming due to the Urban Heat Island Effect.

Four reasons the temperature records are meaningless:

  1. the BOM ignores countless historical records of extreme heat
  2. many older temperatures are adjusted lower, making the modern temperatures appear to be new “records”
  3. many stations are new with a very short history
  4. the BoM isn’t honest about the effect of the adjustments

Who knows what the real records are any more?

The latest claim is Australia’s hottest day in history on 7 January, a BoM declaration that seems to be based on a whole new metric of daily temperature records that estimates national averages in past decades.

Who’s heard of the Australian daily average maximum based on the estimated temperatures from all of the BoM’s weather stations? If you can find past official records of this metric that is grid weighted using 700 to 800 stations, do tell us. The record is made by averaging and grid weighting maxima across the entire continent each day.

Can we expect this every day in the future? Does it make the ACORN dataset obsolete? Will the BoM trumpet this daily temperature when cold fronts roll through? Will the source data be inviolate once the daily statistic is published because subsequent correction or homogenisation of earlier daily data will render the statistic no longer reproducible?

These questions must be asked because only the BoM can perform the calculation on a daily basis – the public must wait up to a year in some cases for the data to appear, and the BoM provides no simple access to all that data.

The BoM is populated with many very competent people but the publication of this 7 January record statistic cannot be checked in any way by the general public, even though one of the objectives of ACORN was to improve the transparency of the BoM’s activities.

Nobody is quite sure how these new calculations work, especially since some of the stations that appear to be included were relocated or simply didn’t exist early or at all in the 20th century. Our independent research team is working to try to figure it out right now. Expect an update in the next day or two. Watch this space.

Related posts:

Thanks especially to Chris GillhamLance and Ian Hill as well as the whole research team for help with this graphic, advice and research. Hat tips to Andy and Chris for some old temperature records.

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