Uncovering the past climate of Australia
A rain gauge used at Sydney Observatory and on display there. The first organised network of weather stations in NSW came with the establishment of Sydney Observatory in 1858. After 1908 the responsibility for weather recording and forecasting was handed over to the newly formed Commonwealth Bureau of Meteorology. Courtesy Powerhouse Museum
A major project to establish Australia’s past climate from the beginning of settlement to the present day has just concluded with a public presentation at the State Library of Victoria on Thursday 2 August 2012. It was a three-year Australian Research Council Linkage project mainly involving researchers at the University of Melbourne, but with contributions from a variety of partners, one of which was the Powerhouse Museum.
The project was based on the principle that is encapsulated in a quote attributed to Winston Churchill: ‘The further back you look, the further ahead you can see’. In other words, to have an understanding of Australia’s climate today and its possible changes, it is essential to have an understanding of its past climate as far back as possible.
Much has been achieved during the three years of the project and the information obtained will be of immediate benefit to organisations like the Bureau of Meteorology and Melbourne Water. There were three aspects:
• Paleoclimate studies that used information from natural phenomena such as tree rings, corals and ice cores to build a long-term record of past climate in South Eastern Australia. This produced reconstructions of rainfall for the last two hundred years and temperature for the last thousand years.
• Finding early meteorological data from historical records, digitising them and applying instrumental control and quality control to make the data comparable with modern data. For example, thermometers in the 19th century were not always kept in in the standard boxes called Stevenson screens that allow air circulation while shielding them from rain and direct sunlight.
• Early written records from diaries of farmers and other people to examine how early settlers coped with the unfamiliar Australian climate.
The Australian climate is widely variable. As Dorothea McKellar wrote, it is a country of ‘Of droughts and flooding rains’. An important result from the project was to establish by comparing the drought of 1998 to 2008, the ‘Big Dry’, with past droughts that there is a 97.1% probability that the rainfall experienced during the period was the lowest since European settlement.
A page from the weather journal of William Dawes. Photo Nick Lomb
As part of obtaining early meteorological data, the records William Bradley made on HMS Sirius during the voyage of the First Fleet to Botany Bay were examined. Bradley took readings every day at noon during the voyage. The astronomer that came with the First Fleet, Lieutenant William Dawes kept a meteorological journal that is in the Library of the Royal Society in London. He made regular weather readings for the journal from his arrival in Australia until his departure from the Colony in 1791 due to a disagreement with Governor Phillip over a punitive expedition against a group of Aboriginal people. The data in Dawes’ journal has been digitised and analysed to show that for the first year or so of the settlement the conditions were cool and wet, but then they became hot and dry.
A barometer used at Sydney Observatory and on display there. In use it would have been fixed vertically and filled with mercury. Courtesy Powerhouse Museum
Later sources of weather data include those from Parramatta Observatory that was established in 1821 by Governor Sir Thomas Brisbane. The geologist Reverend William Branwhite Clarke also made observations as did William Stanley Jevons while working at the Sydney Mint in the 1850s; Jevons later returned to Britain and became a well-known economist.
A recording barometer used at Sydney Observatory and on display there. Courtesy Powerhouse Museum
Another source of early records is George Edwards Peacock who was the official meteorological recorder at South Head Signal Station from 1840 to 1856. Peacock had arrived in Australia as a convict after a trial for fraud. Eventually he was given a conditional pardon and his salary was considerably increased. Peacock supplemented his income by making and selling paintings of the landscape and these paintings are highly prized today. It was Peacock who recorded some of the greatest ever rainfall readings in 1841 and 1844; apparently he had to be up all night constantly emptying the rain gauge to stop it from overflowing.
An important part of the project was the Citizen Science project OzDocs which was about getting volunteers to search through library records and transcribing them. So far 120 volunteers have signed up.
There is information available on the project’s website where the publications page lists an impressive list of publications. As well there are still some important research papers in the pipeline.
This was an exceptionally important project that has shown that much can be learnt from the past. There is still more that could be done and it is a pity that the project has ended. It is to be hoped that some funding can be spared so that this important work can continue.