Australia's average wheat yields, which had more than tripled due to technological advances between 1900 and 1990, did not increase from 1990 to 2015.
Recent research by CSIRO scientists, published in the journal Global Change Biology, found Australia's yield potential (determined by the climate and soil type, managed using best practice and current technology) declined by 27 per cent over the past quarter of a century.
CSIRO team leader Dr Zvi Hochman said the study found Australia's wheat-growing zone had experienced an average rainfall decline of 2.8 millimetres or 28 per cent per cropping season, and a maximum daily temperature increase of around 1 degree celsius from 1990 to 2015.
These observations are consistent with the higher end of future climate change projections for the wheat zone over the coming 26 years.
"Our results are a serious concern to the future livelihood of wheat farmers in marginal growing areas and to the Australian economy, as well as future global food security," Dr Hochman said.
"Wheat farmers are making the most of developments in farming technology and adapting them to their needs. However, their best efforts are merely enabling them to keep pace with the impacts of a changing climate."
He said despite the adverse trend in growing conditions farmers had so far managed to maintain yields at 1990 levels of around 1.74 tonnes per hectare.
This shows that grain growers are closing the gap between potential and actual yield.
"1990 was a watershed year for Australia's wheat industry, with a continued decline trend in yield potential since that year," Dr Hochman said.
The study analysed 50 weather stations with the most complete records across Australia's wheat growing regions, spanning five states from the east to the west coast.
"While some areas have not suffered any decline, others have reduced yield potential by up to 100 kilograms per hectare per year,” Dr Hochman said.