Trawling past climate
[ The University of Melbourne Voice Vol. 6, No. 5
3 May - 13 June 2010 ]
South-eastern Australia is in the grip of one of the worst droughts in recorded history. A project to improve our understanding of the historical impacts of climate extremes will assist with planning for a hotter and drier future. Gabrielle Murphy reports.
A critical issue for policy makers is determining how global warming is influencing Aus-tralia’s natural climate cycles. To this end, the Australian university peak body, Universities Australia, addressed federal parliamentarians on 18 March at Parliament House in Canberra.
The forum sought to answer crucial questions about the signs of climate change in Australia, and how agriculture, cities, and the environment are already changing. Forum speakers, including the University of Melbourne’s Professor Snow Barlow from the School of Land and Environment, and Dr Marie Keatley from the Department of Forest and Ecosystem, also discussed the economic impacts of responding to climate change compared with the cost of doing nothing.
George Santayana’s warning that “those who cannot learn from history are doomed to repeat it” is the cornerstone on which a successful Australian Council Research Linkage project was developed by a team of researchers based in the School of Earth Sciences within the University of Melbourne’s Faculty of Science. The scientists and historians involved in the project have joined forces with water industry experts to establish a better understanding of our natural climate variability.
This project, the first and largest of its kind undertaken in Australia, will reconstruct pre-20th century rainfall, temperature, and atmospheric pressure conditions over south-eastern Australia for the past 200 to 500 years. The scientific and historical investigation will use a variety of sources including palaeoclimate records (tree rings, coral, ice cores and cave deposits), early weather station data and documentary records from newspapers, correspondence, pastoral and farm records, and diaries. The aim is to establish south-eastern Australia’s climate history prior to 1900 to quantify changes in the region’s natural, pre-industrial rainfall and temperatures.
Lead researcher, Dr Joelle Gergis, a geographer and climatologist, and Federation Fellow Professor David Karoly, an internationally-renowned meteorologist, head up a large partnership of organisations including the Australian Bureau of Meteorology, the Met Office (UK), Melbourne Water, the Murray-Darling Basin Authority, the Victorian Department of Sustainability and Environment, Powerhouse Museum, and the National and state libraries throughout Australia.
“Australia has a dry, extremely variable climate with just 100 years of official temperature and rainfall observations,” says Dr Gergis. “This project will extend our climate record using documentary evidence and early weather observations from 1788 to 1900, and annually-resolved palaeoclimate data back to the 1500s.”
Associate Professor Don Garden, an environmental historian and Senior Fellow in the School of Historical Studies will help interpret how climate has influenced Australian society since European settlement. Dr Garden’s latest book, Droughts, floods & cyclones: El Niños that shaped our colonial past has recently been published by Australian Scholarly Publishing.
“Australia’s official weather records only extend back to the late 19th century,” says Dr Gergis. “There is an amazing amount of information about our climatic past recorded in the logbooks of the first European explorers, governors’ correspondence, early settlers’ diaries, newspapers and the works of 18th and 19th century scholars that have hardly been explored for climate information.”
It is this extensive body of material housed in library collections throughout Australia that Dr Garden, postgraduate researchers, and volunteers from the public will trawl through to reconstruct past climate patterns and establish how current changes can be viewed in the context of long-term natural variability.
“Climate history has a crucial significance for contemporary society.” says Dr Garden. “It assists us to understanding some particularly important aspects of human history and, after all, weather and climate have always played a crucial role in shaping human societies.”
A substantial amount of data collection and interpretation has already been completed, and a number of articles and reports published by Dr Gergis and her team researchers in the Australian Meteorological and Oceanographic Journal, Environmental History and Weather. By publishing their findings and conclusions progressively throughout the project, the researchers aim to influence the ongoing climate debate well before the project’s conclusion in 2012.
�€˜HMS Sirius weathering Tasmans-head, 1791�€™, ink wash and watercolour by George Raper, HMS Sirius�€™ mid-shipman, courtesy State Library of New South Wales