Our new research documents the retreat, revealing an accelerating rate of change along Australia's longest coastal dunefield, in South Australia. These beaches are being reshaped in the geological blink of an eye. Wave action is eroding the shoreline and the wind is carrying the sand further inland, where new dunes are being formed. Climate change may be accelerating the rate of change by increasing ocean wind speeds and wave heights. This provides yet another reason to reduce emissions and limit global warming—before our beaches and dunes disappear before our very eyes. Our South Australian study site, the Younghusband Peninsula, is the longest coastal dune system in Australia. It extends some 190km from the Murray River mouth at Goolwa to Kingston in the state's southeast. The shoreline of the central region of the peninsula, near 42 Mile Crossing in the Coorong National Park, started eroding in the early 1980s. Our new research has found the shoreline has eroded about 100 meters since that time, at an average rate of 1.9m per year. Recently this has become much faster and is now up to 3.3 meters a year. That's equivalent to losing a tennis court from the front of your house every seven years. Meanwhile, the dunes are marching inland at an incredible rate of 10 meters a year. This is an extraordinary rate of change. If the shoreline erosion trend continues, it will dramatically change the national park dune system. Dune sands may also invade the iconic Coorong Lagoon, impacting the Ramsar-listed wetland of international significance. Sand could slowly fill the lagoon, transforming the environment and reducing the habitat available for fish, waterbirds and other wildlife. This new field of coastal dunes developed in just over a decade. The landward edge of the dunefield has moved inland more than 100 meters in eight years. Three factors may be causing the shoreline erosion and subsequent dune... |