![]() Historically, megadroughts have profoundly impacted societies and environments. AP Photo/Rick Bowmer Megadroughts and collapsing civilisationsĬurrently, parts of the United States – including Arizona, Nevada and Utah – are in the throes of a megadrought, lasting some two decades. The exposed rocks from receding waters in the Great Salt Lake in Utah, US, which is currently experiencing a megadrought. However, climate change is putting places that have previously endured megadroughts – such as Australia – at an increased risk of megadroughts in future. There is some uncertainty in climate models about the effect of climate change on rainfall at local and regional scales. In contrast, research suggests human-caused climate change is now playing a more important role in amplifying drought conditions, as rising global temperatures increase evaporation. For example, decades-long La Niña conditions have been linked to medieval droughts in North and South America. Historically, droughts have been defined by rainfall deficits, and these deficits can be largely attributed to complex interactions between oceans and the atmosphere over a long time. To look at previous occurrences of megadroughts, we consolidated findings drawn from such datasets and a range of other long-term records. Scientists can gauge local, yearly climate further back in time, by deciphering clues written in tree rings, corals, and buried ice (known as ice cores), among other archives. In Australia, they cover only the last 120 years or so. Instrumental records only go back so far. #Define hohokam fullUnless we incorporate the full potential of Australian drought into our planning, management and design, their impacts on society and the environment will likely worsen in coming decades. They’ve dealt profound damage to agriculture and water supplies, increased fire risk, and have even contributed to toppling civilisations. We show megadroughts have occurred several times across every inhabited continent over the last two millennia. Megadroughts can also be shorter periods of very extreme conditions. Megadroughts can last multiple decades – or even centuries – with occasional wet years offering only brief relief. These are called “megadroughts”, and they’re likely to occur again in coming decades. But our new research finds over the last 1,000 years, Australia has suffered longer, larger and more severe droughts than those recorded over the last century. #Define hohokam crackedMost Australians have known drought in their lifetimes, and have memories of cracked earth and empty streams, paddocks of dust and stories of city reservoirs with only a few weeks’ storage. University of Tasmania and UNSW Sydney provide funding as members of The Conversation AU. University of Western Australia provides funding as a founding partner of The Conversation AU. Pauline Grierson receives funding from the Australian Research Council (ARC). Jonathan Palmer receives funding from the Australian Research Council (ARC). He is also an Advisory Board Member at Weather Promise. Cook's research, including the article this piece is based on, is funded by NASA. Kathryn Allen receives funding from the Australian Research CouncilĪlison O'Donnell receives funding from the Australian Research Council (ARC)īenjamin I. Research Fellow, School of Biological, Earth and Environmental Sciences., UNSW Sydneyĭirector, West Australian Biogeochemistry Centre Professor School of Biological Sciences, The University of Western Australia ARC Future Fellow, University of TasmaniaĪdjunct Research Fellow, The University of Western Australia ![]()
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