Australian farmers are facing more frosts for longer in a "climate surprise" which has been likened to the increase in cyclones and rainfall bombs.
Australian National University climate change scientist Steven Crimp said the increase in frosts would be most apparent in August when an average of up to five events could be expected.
The frost window is now up to four weeks longer in some parts of the country, with the extension driven more strongly by the period of the last frost, according to Dr Crimp's research.
"This change in frost characteristics represents a climate surprise," he told the Australian Bureau of Agricultural and Resource Economics Outlook conference in Canberra on Tuesday.
Other recent climate surprises include one in 1000-year rainfall rates of 96mm an hour seen in Hurricane Harvey which struck the United States and the simultaneous presence of three category four tropical cyclones in the Pacific Ocean last year.
Dr Crimp said the frequency of frosts and the window in which they occur are currently at levels which are predicted to continue until about 2030.
"After 2030 there tends to be a significant change in frost frequency as the warming signal overtakes the frost behaviour," he said.
Peter Holding, who crops and runs sheep on his family property at Harden on the NSW southwest slopes, is a long-time advocate for action on climate change.
He said if stagnating yields due to lower rainfall continued, cropping would become "extremely difficult".
"There's going to be large areas of the wheat belt which I predict will become unproductive," Mr Holding said.
"We need to act decisively and we need to stop emissions before it's too bad."
