Steffen Fritz of the International Institute for Applied Systems Analysis near Vienna and colleagues explain that growing concern about how production of biofuels will impact food security has led to a realization that increased production of biofuels must take place on so-called "marginal land," acreage not suitable for growing food crops, but capable of growing switch grass and other feed stock crops.
However, they said, previous estimates were targeting some areas where land is not marginal, so they did new estimates based on more complete data.
Their analysis, published in the American Chemical Society's journal Environmental Science & Technology, suggests previous studies had overestimated the amount of arable land, had underestimated the amount of land already being cultivated and had not fully considered competing uses for land other than farming, they said.
Their revised estimates show that between 140 million and 2.6 billion acres of additional land could be cultivated for biofuel production, compared with previous estimates of 800 million to 3.5 billion acres.
The analysis highlights the large uncertainties in estimating land availability and such estimates should be used with caution, the researchers said.