Frosts, erosion cause concern

Delegates at the River Reflections annual water conference have heard about the increased risks to agriculture and water infrastructure because of climate change.

In his address, Are we ready? Our changing climate, Professor Mark Howden, the Australian National University’s director of the Institute for Climate, Energy and Disaster Solutions, shared the future watch-points for farmers and water managers.

“We’ve seen a sharp increase in the number and areas affected by extremely high temperatures and this trend is consistent with future projections,” Prof Howden said.

“Somewhat paradoxically — but not news for farmers in this particular region — cold extremes, such as late frosts have also been increasing in the southern (Murray-Darling) Basin because of climate change.

“The risk of damaging late frosts is increasing due to a combination of lower average rainfall and more clear, cold nights along with intensification of the high-pressure systems, which are bringing cold air onto the mainland from deep in the Southern Ocean.

“These late frosts are likely to continue for at least a decade before being overwhelmed by the warming trend.”

Prof Howden said the existing trends towards, on average, less water in the basin — particularly in the south because of lower rainfall — was likely to continue, but would be punctuated by increasing flood extremes.

“Consequently, we will increasingly value our dams and other water infrastructure and have strong incentive to take better care of it,’’ he said.

“Associated with this risk of increasing flood extremes will be increased erosion risk due to higher rainfall intensities.”

He said it was unsurprising that a hotter and drier climate would mean the existing climate ‘drag’ causing lower productivity and profitability of agriculture in the basin was likely to continue and grow.

“What we mean by this is that higher temperatures and reduced rainfall during the growing season is pushing down on potential farm productivity even while improvements in technology and management are pushing them upwards.

“The result is often growth — but much more slowly than would have occurred in the absence of climate change.”

The average reduction of agricultural productivity in Australia from climate change is the same as the global average.

“We expect there will be greatly increased competition for water between agricultural, urban, industrial and environmental users requiring careful attention to policy frameworks and to enhanced water use efficiency,” Prof Howden said.

The inaugural River Reflections conference was organised by the MurrayDarling Basin Authority and held in Griffith in NSW on Wednesday and Thursday, June 9 and 10.

The MDBA said River Reflections provided the space and time for the diverse communities and industries of the Murray-Darling Basin to come together, and was an opportunity to share innovations in water management, knowledge and lessons learned while celebrating achievements.