RFF study challenges ‘Searchinger Hypothesis’ land-use emissions

Source: Amanda Peterka, E&E reporter • Posted: Friday, November 8, 2013

Five years ago, a Princeton University study predicted that ramping up biofuel production to meet the federal renewable fuel standard would increase greenhouse gas emissions by stimulating land-use changes in foreign countries.

Researcher Timothy Searchinger’s study provided the basis for “food versus fuel” concerns raised by opponents of corn ethanol, but it was also used to project that shifting to non-corn-based biofuels would cause the same types of problems. Critics worried that the harvesting of trees for fuel especially would lead to the decimation of forests abroad.

But it doesn’t have to be that way, according to a new study released today by Resources for the Future.

The RFF study disputes the application of the “Searchinger Hypothesis” to advanced biofuels and finds there is more than enough available land to economically produce second-generation fuels without increasing carbon emissions elsewhere or compromising the ability to produce food.

“Major increases in bioenergy fueled by biomass need not place substantial additional demands on US agricultural lands,” the study found. “This would raise serious doubts about the applicability of the Searchinger Hypothesis, as this finding would imply that increased bioenergy production in the United States will have limited impact on cropland use domestically and thus land conversion abroad.”

The study, published online today, is authored by RFF senior fellow Roger Sedjo, Ohio State University resource economist Brent Sohngen and former RFF research assistant Anne Riddle.

Using U.S. Geological Survey data, the authors analyzed the availability of marginal lands, or those not suitable for profitably planting cash crops, in the United States, and used a model to project how much woody biomass could be produced without compromising food production.

They found that between 500,000 and 1 million hectares could be available for using wood that can be converted to motor fuel. Of that, the large majority of wood production moving to the biofuel sector would come from the existing pulpwood sector.

The large potential use of pulpwood comes from a combination of stagnating demand for paper in the United States and a large existing amount of area dedicated to pulpwood plantations.

“An important implication with regard to the Searchinger Hypothesis is that quite high levels of future bioenergy demand could be met within the United States,” the authors wrote, “through a combination of new fuelwood plantations and the increased use of wood types traditionally used for pulpwood.”

Newly developed land for woody biomass production will play only a small role because of the costs it takes to establish new tree plantations, the authors found.

“These sources can economically produce large levels of biomass without compromising crop production, thereby mitigating the land conversion and carbon emissions effects posited by the Searchinger Hypothesis,” the study found.

The authors note, though, that meeting biofuel demand with wood depends on companies developing economically viable technologies to convert wood into cellulosic ethanol.