THE maths are fairly straightforward - global crop production needs to double by 2050 to feed a projected population of nine billion - but the current reality is way off.
Researchers at the University of Minnesota analysed about 2.5 million agricultural statistics from around the world, and concluded that crop yield increases are far below the required rate of gain to meet 2050 targets.
The team, from UM's Institute on the Environment, looked at maize, rice, wheat, and soybean, which are collectively responsible for about two-thirds of the crop calories harvested around the globe.
Their analysis revealed that over the past two decades, average yield improvements for these crops only grew between 0.9 to 1.6 per cent per year, "far slower than the required rates (about 2.4 per cent) to double their production by 2050 solely from yield gains".
Troublingly for Australia, the analysis confirmed that wheat yield growth has declined across the Australian wheatbelt regions.
Although the researchers don't say so, the falling rate of growth in Australia's wheat yield has been influenced by a run of adverse seasons.
If current trends are projected out to 2050, the rate of yield gain in the Australian wheat crop will be negative or negligible.
The biggest rates of gain in wheat are projected to come from the application of technology in regions like China, north-west India and across the black soils of Russia and the Ukraine.
Overall, the researchers concluded, "there is a 90 per cent chance that the total global production increase from yields alone would be between 34-101pc for maize, 21-59pc for rice, 4-76pc for wheat, and 13-84pc for soybean by about 2050".
"Thus, if these yield change rates do not increase, land clearing possibly would be needed if global food security is to increase or even maintained."
Expanding croplands would come at a high environmental cost to biodiversity and carbon emissions, the authors noted.
"Alternatively, additional strategies, particularly changing to more plant-based diets and reducing food waste can reduce the large expected demand growth in food." For more information on "Yield Trends Are Insufficient to Double Global Crop Production by 2050" Deepak K. Ray et al visit www.plosone.org