What was Perth’s climate like from 1830 to 1875?

Very little is known about the past climate of Perth, Western Australia, in the 1800s. Our team has recently pieced together the oldest known daily weather observations from south-western Australia that spans 1830–1875.

There’s a strong case for increasing 19th century climate data rescue efforts in the south-western region of Australia, due to the vulnerability of this area and its important geographic location for understanding weather patterns across Australia. With a more complete understanding of the past climate, we can better prepare for extreme events which are predicted to increase in frequency and severity.

The Australian Bureau of Meteorology’s State of the Climate 2020 report noted that cool season rainfall in southwest Western Australia (WA) has deceased since 1970 due to an increase in surface pressure across southern latitudes – a known response to climate change. Lower winter rainfall and higher temperatures mean the fire seasons are getting longer, with the February 2021 bushfires in Perth Hills proving as case in point, with around 11,000 hectares and over 85 homes destroyed

Improving our understanding of long-term climate variability from the Southern Hemisphere is critical to quantifying future changes in Australia. To date, the majority of historical data recovery efforts across the country have centered on the colonial centres of south-eastern Australia.

To date, research on the past climate of 19th century Australia has focused on south-eastern Australia. Combined with the important geographic location for understanding how weather systems move across southern Australia, there’s a strong case for increasing data rescue efforts in the south-western region. Source: Ashcroft et al., 2014.
To date, research on the past climate of 19th century Australia has focused on south-eastern Australia. Combined with the important geographic location for understanding how weather systems move across southern Australia, there’s a strong case for increasing data rescue efforts in the south-western region. Source: Ashcroft et al., 2014.

Perth is located in the southern storm-track associated with prevailing westerly winds, which makes it important for understanding changes in the weather systems over time. Comparing observations from this site with the data we have for south-eastern Australia will help scientists understand how weather patterns have changed over southern Australia.

Sharing our research on the past climate of south-western Australia

In February 2021, we’ll present our most recent research on the Perth region as part of the 2021 Australian Meteorological and Oceanographic Society (AMOS) annual meeting and international conference. In a session titled The story of climate in Australia: learning from the past and planning for future impacts, our research assistant Zak Baillie will present a new historical climate dataset for southwestern Australia, covering the period 1830 to 1875. 

This is the first time that historical weather observations from south-western Australia during the 19th century have been analysed in such detail. It includes near-continuous daily observations of air pressure, temperature and wind along with weather remarks, including rain days. 

The observations we studied were recorded in 16 handwritten weather journals taken from the Swan River colonial settlement of Perth and begin shortly after the first European settlement of the region in 1829. These weather journals are currently the oldest meteorological observations for Perth. 

The Perth Meteorological journals we recently analysed are a near-continuous sub-daily dataset of temperature, pressure, wind direction and weather remarks from 1830 to 1875.
Source: National Archives of Australia.

The team compared historical observations with modern instrumental observations from Perth. The analysis identified some interesting examples of significant storms and heatwaves that demonstrate the potential of using historical observations to analyse past extremes and their societal impacts. 

For example, a significant heatwave identified in the historical observations was verified by looking at newspapers published at the time. The newly-transcribed historical journals showed an extreme heatwave from December 28 to 30, 1868. By searching the National Library of Australia’s digital collections on Trove, we found numerous newspaper accounts of this heatwave detailing the severity and impacts of the event.

Unfortunately there is still a gap in Perth’s historical climate record from 1876 until the Bureau of Meteorology’s records begin in 1900. We’ve been lucky enough to find some journals from Perth which will complete 20 years of these observations – but they need to be transcribed before we can analyse them. 

Around April this year, we’ll launch a citizen science project to transcribe more journals from the Perth region from 1880 to 1900. Click here to sign up to our e-newsletter, and you’ll be notified as soon as we launch our next citizen science transcription project.

Linden Ashcroft wins a science outreach award

In other exciting news, our very own Dr Linden Ashcroft has been awarded the AMOS Science Outreach Award at the 2021 AMOS conference. The accolade recognises AMOS outreach ambassadors who inspire other AMOS members to undertake science engagement activities. It also recognises those who engage with the public, politicians, schools, businesses and communities, to educate and inform those groups on topics associated with AMOS themes. 

In 2019, our Director Dr Joëlle Gergis was awarded this same accolade, so it’s an honour to have two members of our team now recognised for their strength in engagement and outreach.

Linden has used her expertise in historical and future climate change to educate the broader public, through dozens of TV, radio and newspaper interviews. This includes her extensive radio work with the Einstein A-go-go program on 3RRR where she has a semi-regular slot explaining and discussing recent science, technology, engineering and maths (STEM) stories to the broader public. Linden’s outreach has helped influence public opinion on past and future climate change through educating people around these topics. 

Linden’s clear and easy-to-understand article “Letter to a weather station” was published in a collection of The Best Australian Science Writing 2019. In early 2019, Linden was recognised as a Science and Technology Australia Superstar of STEM, a program established to create a critical mass of outstanding Australian female scientists and technologists as role models for young women and girls. 

Linden’s effective communication and passion for her research has energised efforts to harness the power of citizen scientists in helping to transcribe old weather records. This vital work that Linden has helped pioneer allows climate scientists to extend the record of Australian meteorological observations back well into the 19th century.

Get involved in our upcoming citizen science project to help transcribe 20 years’ of historical climate records from Perth. Don’t forget to sign up to our e-newsletter, so you’ll be notified as soon as we launch.