The recent floods in 2020 and 2021 on Australia’s east coast were damaging and destructive. It’s easy to forget that they occurred just a year after a large and sustained drought which affected many of the same regions.
As our climate continues to warm, the challenge of ‘too much’ or ‘too little’ water will be exacerbated by the background trend of increasing temperatures. Climate information and projections are providing essential information for many Australian sectors that need to plan effectively for future water supply.
Here are 5 things you should know about the Hub’s work on drought and water futures over its lifespan of research.
East coast lows that are more intense will likely occur less frequently in the future
East Coast lows (ECLs) are low-pressure systems that form off the East Coast of Australia and can cause heavy rainfall, strong winds, large waves, widespread flooding and coastal erosion.
Projections indicate that we can expect less frequent ECLs in the future, however, this does come with a caveat: ECLs that do occur could be more intense and more destructive.
But rainfall from intense east coast lows is projected to be higher
In a warmer world, the atmosphere holds more moisture, meaning we can expect very intense rainfall events (such as those associated with ECLs) to increase in intensity and volume.
These future changes for ECLs are similar in some ways to what is projected for tropical cyclones, where fewer are projected to occur but with more intense rainfall.
With 85 per cent of Australia’s population living near the coast, increasing rainfall intensity and volume has very real implications.
We produced an updated set of projections of water availability for Australia
While wet and dry years will continue to occur into the future, overall, Australia will experience a hotter climate, and for many Australians, particularly in the south, the future will be drier. To help the water and related sectors adapt and respond to the challenge of water availability, researchers have updated existing projections of water availability across Australia. The projections indicate a significant reduction in streamflow in southern Australia as a result of the background drying trend, while the direction of rainfall and runoff change in northern Australia remains unclear.
We also helped close in on critical gaps in projections of drought
At any given time, regions in Australia are prone to drought. This is primarily a result of our large natural climate variability. However, parts of Australia are likely to spend more time in drought under a warming climate, particularly in the southeast. To help build resilience and preparedness under a changing climate, Hub researchers produced drought projections until the year 2100. These projections included time spent in drought, mean drought duration, drought frequency and drought intensity.
The projections reveal that more severe drought conditions are projected to take place under climate change, including more time spent in drought. However, there may not necessarily be an increase in drought frequency.
And have identified the risk of flash drought at different times in the year
From near-normal conditions to extreme drought in just a few weeks, flash drought seemingly comes from nowhere, with little warning or time for preparation. Vegetation dries rapidly, and crops and pastures wither.
With a focus on understanding when, where and why flash drought occurs, Hub researchers worked to identify the risk of flash droughts for Australia, and the tools most useful for monitoring them.
While they are most prevalent during summer and autumn, Hub research findings indicate they can occur year-round, even during winter in southeast and southwest Australia.
The research captured in these synthesis products was undertaken by the following Hub projects: