Nov 2 2020
According to a study headed by the University of Queensland, mega-droughts, or droughts that persist for more than twenty years or even longer, are expected to increase due to climate change.
Professor Hamish McGowan gaining access to stalagmites around 120 meters below the surface in the Grotto Cave, NSW. Image Credit: The University of Queensland.
Hamish McGowan, a Professor from the University of Queensland, stated that the results indicated climate change would result in decreased winter snow cover, increased water scarcity, wind erosion, and more frequent bushfires.
The discovery came following an analysis of geological records from the Eemian Period—129,000 to 116,000 years ago—which provided a proxy of what people could anticipate in a hotter and drier world.
We found that, in the past, a similar amount of warming has been associated with mega-drought conditions all over south eastern Australia. These drier conditions prevailed for centuries, sometimes for more than 1000 years, with El Niño events most likely increasing their severity.
Hamish McGowan, Professor, University of Queensland
The research team was occupied in paleoclimatology—the study of historical climates—to analyze how the world will appear due to global warming over the following 20 to 50 years.
The Eemian Period is the most recent in Earth’s history when global temperatures were similar, or possibly slightly warmer than present. The ‘warmth’ of that period was in response to orbital forcing, the effect on climate of slow changes in the tilt of the Earth's axis and shape of the Earth's orbit around the sun.
Hamish McGowan, Professor, University of Queensland
McGowan added, “In modern times, heating is being caused by high concentrations of greenhouse gases, though this period is still a good analogue for our current-to-near-future climate predictions.”
The team collaborated with the New South Wales Parks and Wildlife Service to determine stalagmites in the Yarrangobilly Caves situated in the northern section of Kosciuszko National Park.
Tiny samples of the calcium carbonate powder found inside the stalagmites were gathered, examined, and dated at UQ.
This analysis enabled the researchers to determine periods of considerably decreased precipitation at the time of the Eemian Period.
They’re alarming findings, in a long list of alarming findings that climate scientists have released over the last few decades. We hope that this new research allows for new insights to our future climate and the risks it may bring, such as drought and associated bushfires. But, importantly, if humans continue to warm the planet, this is the future we may all be looking at.
Hamish McGowan, Professor, University of Queensland
The study was part of a project that was financially supported by Snowy Hydro Ltd to develop better insight into climate variability in a warmer world and the effect on the hydroclimate of southeast Australia.
Journal Reference:
McGowan, H., et al. (2020) Evidence of wet-dry cycles and mega-droughts in the Eemian climate of southeast Australia. Scientific Reports. doi.org/10.1038/s41598-020-75071-z.