University of Melbourne Magazine

Hot on the trail

  • Hundreds of University staff and students are engaged in critical climate change research. Some operate in far-flung locations, others are much closer to home, writes Tim Thwaites (BSc(Hons) 1974, Trinity College, Janet Clarke Hall).

    Professor David Karoly

    Professor David Karoly has been documenting the changing climate for more than 30 years. Picture: Justin McManus

    For a legion of researchers, the search for clues as to how our climate is warming can be as much about hard toil as hard science.

    And doing it in some of the most remote and inhospitable places on Earth.

    For Dr Michael-Shawn Fletcher it has meant trekking into the Tasmanian wilderness in winter – as he did last year – to drill into the bed of a pristine lake, after first cutting through a 20-centimetre crust of ice.

    Over the past 15 years, Fletcher (BEd(Sec) 1997, PGDipArts 2000, PhD2009), has been extracting sediment cores – with the diameter of a jam jar and up to 10 metres long – from lake beds all over the Southern Hemisphere: in Chile, New Zealand, south-western Victoria, the south coast of NSW and, recently, Litchfield National Park near Darwin.

    Many of his sites are so remote that his floating platform and drilling equipment have to be dropped in by helicopter.

    For his Tasmanian research, Fletcher, from the University’s School of Geography and Resource Management, was operating in Ben Lomond National Park, south-east of Launceston.

    Why do it? “Lakes are receptacles of atmospheric information through time,” he explains.

    “It can be in the form of dust, pollen, or charcoal, or even the products of surface chemical reactions that are absorbed into the plants and animals living in the lake. Eventually all of these settle into the sediments at the bottom.”

    His sediment cores provide clues to what has happened over time.

    The deeper one drills, the further back one goes. Pollen, for instance, tells you what plant species were around; dust contains the minerals that were present and tells you about the erosion they were subject to; and charcoal can show the frequency and extent of fire across time and space.

    All are indicators of past climate.

    Dr Michael-Shawn Fletcher

    Dr Michael-Shawn Fletcher on a frozen lake in Tasmania

    Already, Fletcher has found an astonishing correlation between the occurrence of fires and climate variation across the entire hemisphere, going back tens of thousands of years.

    Earlier this year, he and student Michaela Mariani published a paper that should assist in predicting high-risk fire seasons in Tasmania.

    It linked the drying of western Tasmania and the subsequent increased frequency of bushfires over the past 1000 years with the southward movement of the westerly winds known as the Roaring Forties.

    The recent depletion of the ozone layer in the upper atmosphere, or stratosphere, has previously been shown to be a driver of this process.

    It correlates closely with an increased frequency of fires in the past 30 years. Fletcher believes this is evidence of human-induced climate change at work.

    He is one of hundreds of academic staff, post-doctoral fellows and graduate students at the University of Melbourne studying aspects of what many regard as the world’s most significant challenge.

    They span a broad range of disciplines from physics and chemistry to zoology and botany, engineering and the medical sciences to economics, law and politics, as well as many interdisciplinary teams.

    Their work ranges from the highly theoretical, such as constructing numerical models from basic physics, to the eminently practical, such as studying how best to plant “green” roofs and wall gardens. Some of what they find is being used to guide the University itself.

    “Universities are communities with similar populations to towns and large businesses, facing many of the same challenges of climate-change mitigation and adaptation,” says David Karoly, Professor of Atmospheric Science in the School of Earth Sciences.

    “They can provide a test-bed as to how to successfully transform into a 21st century, climate-adapted, sustainable community.”

    Professor Karoly has been documenting and championing action on climate change for more than 30 years.

    But there is still much work to do. Although the existence of human-induced climate change is as well documented scientifically as almost any phenomenon, he says, we are still unclear as to how it will all work out in detail, particularly at a regional and local level.

    And we also need to know how best to respond to it practically.

    “For instance, one important thing is to understand extreme weather and climate events and the link to human-caused climate change. You can already do this, but only for some events, on some occasions.”

    That’s why a major activity of his research group involves using an international citizen science program, Weather@home ANZ, to develop ways of understanding the connections between climate change and such events as floods, cyclones and heat waves.

    The problem is a lack of available data to compare what is likely to happen due to the current build-up of greenhouse gases against what would have happened without it.

    The solution is to run hundreds of thousands of simulations of different conditions using regional and global climate models on the home computers of volunteers.

    And the result is a growing number of papers showing, for example, that the present devastating coral bleaching event on the Great Barrier Reef has been made 177 times more likely by climate change. And, if we do not act, within a couple of decades such events could occur every two years.

    Apart from leading his own research group, Professor Karoly encourages research in interdisciplinary groups and activities across the University.

    “I saw how I could use what I had learned. And I haven’t looked back.”

    Last year, for instance, he and his colleagues were instrumental in the publication of Appetite for Change, a report on the practical impact of climate change on food production in Australia, together with a cookbook, Planet to Plate.

    It all goes back to why he became interested in the subject in the first place. A city boy, he grew up with a love of outdoor activity – bushwalking, rockclimbing, skiing. This engagement continued at university, where he studied maths and physics.

    Drilling for evidence: Dr Michael-Shawn Fletcher

    Drilling for evidence: Dr Michael-Shawn Fletcher sets up a rig in his hunt for evidence of climate change.

    “On one trip, I stood and watched clouds forming as the wind blew over a ridge. I realised that this was just fluid dynamics at work,” he says. “So, that’s what I chose to do, because it was something meaningful to the average person in the street. I could explain it to my mother, the non-scientist in my family.”

    If Karoly and other researchers need evidence that things can change, they can draw on a recent example.

    Successful international action has raised ozone levels in the stratosphere – helping to heal the Antarctic ozone hole – verification of which was announced in late June.

    This result has been attributed to the Montreal Protocol, signed in 1987, under which the world community agreed to reduce the release of ozone-depleting compounds containing chlorine and bromine, used as refrigerants and in aerosol sprays.

    And that’s where Dr Robyn Schofield, of the School of Earth Sciences, comes in. She originally trained in quantum chemistry, “but I knew that I wanted to do something applied, something that would make a difference some day”.

    That opportunity presented itself when she made a trip to a relatively remote New Zealand observing station in the central South Island, one of five worldwide that measures the “clean” background composition of the upper atmosphere.

    “I saw how I could use what I had learned. And I haven’t looked back,” she says.

    Dr Schofield now specialises in measuring the levels at different altitudes of reactive chemicals and aerosols, typically greenhouse gases other than CO2, such as ozone.

    She does this by studying the variations in the absorption of sunlight, particularly its ultraviolet component, as its path through the atmosphere changes while the sun is setting.

    This research has taken her all over the world, including Antarctica – and it has producing practical results.

    She is now part of a team developing AIR-BOX, a custom-built laboratory that fits into a shipping container to carry out comprehensive atmospheric monitoring and take measurements in difficult places, such as near the Great Barrier Reef.

    Its deployment would be another small step in a massive interdisciplinary effort.

    It’s not that easy being green . . .

    The University has committed to significantly reducing its greenhouse gas emissions.

    Earlier this year, it signed a Sustainability Charter that “sets out the values and principles to be embedded throughout [its] operations, and identifies the commitments required to achieve a sustainable future”.

    But that’s not easy, as Professor David Karoly points out. “How do you grow your business at the same time as continuing to reduce emissions?”

    Devising courses that incorporate sustainability, establishing climate-change research groups, and engineering clever ways to reduce energy use are essentially bread-and-butter activities for universities.

    Sustainability Charter

    But issues such as divestment of fossil fuel stocks and reducing the level of academic travel, he says, are not.

    Still, the University is making headway, with help from its interdisciplinary research bodies, such as the Melbourne Sustainable Society Institute.

    The Institute brings together academics at the forefront of sustainability knowledge and encompasses research groups such as the Melbourne Energy Institute and the Australian-German Climate & Energy College, a partnership between the University and three universities in the Berlin-Potsdam area.

    The University, through the Institute, is also involved in all manner of outreach activities, such as public seminars on climate change policy and research, and support for Climarte, an alliance of people in the arts committed to using their skills to record, reflect and support the struggle for a safe climate.

    Alumni can contribute to the development of the University’s Sustainability Plan – the strategy for meeting the charter’s goals.

    For information go to: sustainablecampus.unimelb.edu.au