Streamflow has generally increased in northern Australia and decreased in southern Australia since the mid-1970s  . Declining river flows since the mid-1970s in southwest Australia have led to changed water management . The large decline in river flows during the so-called 1997-2009 Millennium drought in southeast Australia resulted in low irrigation water allocations, severe water restrictions and major environmental impacts . The drying in southern Australia highlighted the need for hydrological models that adequately account for climate change . The decline in streamflow was largely due to the decline in cool-season rainfall   , when most of the runoff in southern Australia occurs.
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report