Chief Climate Commissioner Tim Flannery says South Australian wheat farms will become unviable if more is not done to address climate change.

A recent study has found that a two degrees Celsius increase in average temperatures shortens the growing season by nine days and reduces total yield by up to 20 per cent.

Professor Flannery says if current warming trends continue there will be increasing concern about the future of wheat growing in the state.

"So if we look at 90 years or so, we can see that if we continue emitting globally as we are, that ... cropping may just not be possible throughout most of the state and that we'd see catastrophically large declines in productivity," he said.

Professor Flannery says the state has achieved a lot in terms of wind-powered electricity generation but more needs to be done in other areas for cropping to remain viable.

"As we look into the future for South Australia, with increasing temperatures, declining water availability and changing seasons, there are some real threats to wheat cropping, particularly in South Australia, but also productivity through the Murray-Darling Basin, particularly the lower end of the basin in South Australia," he said.