Climate reconstructed

This article was originally published in the December 2020 issue #89 of COSMOS magazine.

Citizen scientists are transcribing historical weather journals to help scientists better understand Australia’s climate history.

In 1896, there was a great celebration for the unveiling of West Australia’s weather observatory’s foundation stone in Perth Park (now Kings Park and Botanic Garden).

That year, Premier John Forrest said that the observatory: “… showed that in the time of our prosperity we were trying to elevate and improve the public mind and to do something for the encouragement of the arts and sciences… Western Australians might be proud they were doing something to enlighten their people and to join hands with the scientists all over the world.”

This journey of scientific discovery continues. Climate scientist Dr Joëlle Gergis, from the Australian National University, is leading the effort to rescue historical weather records kept at the Perth Observatory as part of an international effort to recover weather records from centuries-old documents and ship logbooks from around the world. The project is being completed with the help of citizen scientists using the Zooniverse online platform.

“By looking back at history, scientists can learn a lot about how climate variability and extremes impacted Australian society in the past,” says Gergis. “In Australia, historical records have been relatively untapped for use in climate change research.”

Current understanding of Australia’s weather and climate is based on the records kept since the Australian Bureau of Meteorology (BoM) began taking official records in 1900. Yet daily accounts of the weather have been recorded in Australia since the arrival of the First Fleet. The problem is locating and transcribing them. It’s estimated that just half of the known historical weather observations globally have been digitised.

“Perth has daily weather observations starting in 1830,” says Gergis. “There are gaps in the record between 1876 and the beginning of the Bureau of Meteorology’s records in 1900. We are hoping that observations taken from the Perth Botanical gardens will provide a big part of the missing link needed to connect these records.”

Perth is a particularly important region for studying past climate.

“Research shows that rainfall declines in the Perth region have been caused by a southward shift in the storm track since the 1970s. This means that rain that used to fall on the land now ends up in the Southern Ocean,” says Gergis.

“The aim of this project is to reconstruct Perth’s daily weather record back to 1830. This will help us identify changes in rainfall and temperature variability and extremes and how these observations compare to modern records. By looking at historical pressure observations we can determine the weather systems that moved across southern Australia in the past and see how they might have changed.”

The National Archives of Australia’s collection contains weather records kept at the site of the Perth Survey Office and Botanical Gardens from 1880 to 1900, when the BoM’s modern records began, so this project will help connect observations from 1830 to the present (although a gap from 1876 to 1879 still remains).

Once complete, it will be Australia’s longest daily weather record, and one of the longest in the Southern Hemisphere.

Peter Smith is one of those volunteering to help. He worked for the BoM for 36 years in pre- and post-computer times, manually updating Melbourne weather records dating back to 1860. “I got involved in this online project because I’ve always been fascinated by weather and history,” he says.

“For me, it’s important to be a part of these projects that are saving and sharing all the available old weather data online, so it can be analysed and kept forever, and be used for climate change research.”

“And, one of the best things about it is having direct contact with the actual researchers through Zooniverse.”

Gergis says that Smith’s meteorological background and ability to decipher the sometimes-tricky handwriting has been an asset. But you don’t need to have any experience working with scientific data; anyone can contribute.

“The new Perth project will digitise over 60,000 observations that have not been analysed for a very under-studied part of the country,” says Gergis.

“The data transcribed by citizen scientists will be invaluable. This research will really help the climate science community to better understand past extremes and how Australia’s climate might change in the future.”

– Written by Caitlin Howlett, Fenner School of Environment & Society at the Australian National University.

Read a related article by COSMOS online: Renewed interest in weathered records