The MDB is Australia's largest, most economically important and politically complex river system . The MDB supports agriculture worth AUD$24 billion/year, 2.6 million people in diverse rural communities and important environmental assets including 16 Ramsar listed wetlands . Climate change is projected to substantially reduce water resources in the MDB , with the median projection indicating a 20% decline in average annual runoff under 2.2℃ average global warming  . This reduction, plus increased demand for water in hot and dry conditions, would increase the already intense competition for water  .
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report