One of Australia’s top hydrologists says the new IPCC report has implications for water management and flooding. 

The Intergovernmental Panel on Climate Change (IPCC) 6th Assessment Report on Impacts, Vulnerability and Adaptation, was released this week.

It indicates that a projected decline in future winter and spring rainfall in south-eastern Australia will be amplified in the decline in water resources. 

The analysis suggests this will continue to exacerbate the already complex challenges of managing water for competing demands in Australia.

“The future in the Murray-Darling Basin will be hotter and drier, but there is considerable uncertainty around how much and by when, compounding the management and adaptation challenges,” says Dr Francis Chiew, an IPCC lead author, Senior Principal Research Scientist (Hydrologist), CSIRO Land and Water.

“The Murray-Darling Basin is a highly variable system, and we’d expect to see long wet periods and dry periods, but climate change will increase the frequency of droughts that people, and the ecosystems, need to cope with and recover from.

“The impacts of droughts over the recent decades, and projections of a drier future, have accelerated significant water policy reforms - in particular, the Basin Plan. These are positive adaptations as they help buffer the system against drought. 

“But they can also be maladaptive by perpetuating unsustainable water and land use under ongoing climate change. 

“In any case, more will need to be done, with the projected decline in water resources being potentially greater than the water recovered for the environment.

The IPCC report also notes that highly extreme rainfall will become more intense under a warmer climate. 

This will increase flood risk in cities, in built-up urban areas, and in small catchments, where the high rainfall can quickly become flash floods.

“There are good examples of adaptation to changing flood risk, and they are mostly reactive and incremental in response to floods and heavy rainfall events,” Dr Chiew says. 

“Recent initiatives like the Australian Climate Service, the National Recovery and Resilience Agency and Drought Resilience initiatives, are positive steps to helping address risks from floods, fires, droughts and other hazards. 

“These are important because of the cascading and aggregated impacts from multiple hazards on people, infrastructure, services and supply chains.”