While the map shows that there is huge potential for increasing biofuel production without increasing its footprint, the authors of the report warn that, even if all areas are brought up to median levels of intensification, there would still not be enough production to meet the US biofuels target for 2022, let alone the global target.

"The US biofuels target for 2022 is 136 billion litres," Matt Johnston, from the University of Minnesota in the US told environmentalresearchweb. "Even if all countries across the globe were to increase yields for all 20 of the crops in our study simply to median levels of what was possible in the year 2000, we estimate that global biofuel production could be brought up to only 121 billion litres. This re-affirms the urgent need for next-generation biofuels because agricultural biofuels alone cannot meet the global need."

Using M3 cropland datasets, Johnston and his colleagues calculated median yields and yield gaps for 10 ethanol and 10 biodiesel crops. They produced both global and individual results for 238 countries, territories and protectorates (157 of which are reported in their paper in Environmental Research Letters (ERL)). Instead of relying on plant physiology and optimal interception of solar radiation to determine maximum physiological production potential, their analysis takes a new, data-driven approach based on existing reported yields and cultivated area.

The researchers looked at more than 1200 country/crop combinations to pinpoint which crops in which countries could benefit most from intensification of farming practices. For example, they calculated that in Macedonia 28,900 hectares are currently used for maize production. If the productivity of 20,800 of these hectares was brought up to global median levels, the country could produce an extra 36.2 million litres of ethanol. In another example, if Honduras was to intensify just 9,800 hectares of its 46,500 hectare sugarcane production, it could produce an extra 48.8 million litres of ethanol.

"Our map identifies concentrated areas of low-yielding agriculture that might benefit from targeted implementations of modern agricultural practices," said Johnston. "We hope that it will help researchers and policymakers to more accurately understand spatial variation of yield and agricultural intensification potential. We also hope that our study will help policymakers to better use existing infrastructure and optimize the distribution of development and aid capital so that responsible intensification might be promoted over further expansion of agriculture."