For the most part, farmers put their cropland to more intense use rather than convert forests and grasslands because of demand for biofuels in recent years, says a study by the Center for Agricultural and Rural Development. The study say outside of Africa, “15 times more land use change occurred at the intensive margin than at the extensive margin.” Intensive margin “includes increased double-cropping, a reduction in unharvested land, a reduction in fallow land, and a reduction in temporary or mowed pasture” while extensive margin means bringing new land into agriculture.
“The pattern of recent land use changes suggests that existing estimates of greenhouse gas emissions caused by land conversions due to biofuel production are too high because they are based on models that do not allow for increases in non-yield intensification of land use. Intensification of land use does not involve clearing forests or plowing up native grasslands that lead to large losses of carbon stocks,” conclude the authors, Bruce Babcock and Zabid Iqbal.
They say the costs of converting land to agricultural use is high, so more efficient use of existing land is the preferred option. “This finding is not necessarily new and is consistent with the literature that shows the value of waiting before investing in land conversion projects,” say the authors. “However, this finding has not be recognized by regulators that calculate indirect land use.” The study notes the EPA, the EU Commission and California clean-air regulators forecast significant emissions of greenhouse gases due to conversion of forest and pastures into cropland in response to demand for feedstocks for making biofuels.