INTERNATIONAL scientists have highlighted the urgent need for mitigation to avoid water storage declines and increased droughts and the big role farmers in Australia, particular in the south, stand to play in that.
By the end of this century, the global land area and population living in extreme-to-exceptional drought could more than double, research directed from Michigan State University in the United States has found.
The stark warning emerged from the extensive study, which also points to the largest water declines being in Australia and South America.
The key implication is that climate change mitigation is now critical to avoid adverse water storage impacts and increased droughts, and the need for improved water resource management and adaptation is pressing.
Given that agriculture is the largest land use in Australia and agricultural water use is by far the largest in terms of total global water use, the role of farmers in this space will be crucial, according to one of the key scientists involved in the work, associate professor Yadu Pokhrel, from the department of civil and environmental engineering at MSU.
The study, published this week in Nature Climate Change, looked at the water available globally in lakes and reservoirs, rivers, wetlands, canopies, snow and ice, soil and groundwater - collectively called terrestrial water storage.
"In particular, increased agricultural water use could exacerbate declining TWS in regions like southern Australia where climate change is expected to cause large declines in water availability and increase related droughts," Dr Pokhrel, lead author, said.
The need for improved water management was the key message from the research, he said.
"There is now an urgent need for climate change adaptation, especially by reducing water use in regions where TWS are projected to decline sharply - southern Australia being one of those regions.
"Mitigation is critical to avoid detrimental effects of reduced TWS on a range of systems, including agriculture."
The authors explain TWS modulates the hydrological cycle and is a key determinant of water availability and an indicator of drought.
Future changes in TWS and the linkages to droughts have been largely unexamined to date.
The researchers involved in this study used ensemble hydrological simulations to show that water is expected to decline over the next 80 years, especially in the Southern Hemisphere.
By the late twenty-first century, two-thirds of global land could experience a reduction in TWS.