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New Studies Question Cellulosic Biofuels

March 5, 2009
A new study from MIT’s Joint Program on the Science and Policy of Global Change examines what it calls the Unintended Environmental Consequences of a Global Biofuels Program. Unintended consequences seems to be the watchword of the year. The authors posit that there will be a feedback loop from climate change and policies that promote biofuels to address it. Climate change itself will affect the productivity of land, shifting agricultural production to new areas, and causing land use change, according to the authors. At the same time, a growing population will create additional demand for food while climate change policies promote biofuels, both of which require more land, causing land use change and associated emissions, which in turn affects the ability of farmers to meet food and fuel demand.

The authors develop a “deforestation” scenario, in which new agricultural land comes from the cheapest, most readily available source, which includes ecologically sensitive forest land. They develop another “intensification” scenario, in which ecologically sensitive hotspot lands are protected, but new agricultural land again comes from the cheapest source.

The authors expand even further the idea of indirect land use. Unlike earlier papers that assume that use of grain for biofuels in the United States will require farmers elsewhere to grow additional grain to meet market demand, leading to land use change, the current authors define indirect land use as “when biofuels production moves on to croplands or pastures, and causes new forest clearing to relocate agriculture.” By attributing land use change to any use of land, rather than food crop market mechanisms, they apply the land use change theory to cellulosic biofuels.

This isn’t the first time members of this group have raised the question of “unintended consequences” for cellulosic biofuels. See my earlier post regarding “Sustainable Biofuels Redux” in Science. Brent Erickson here at BIO corresponded with the authors at that time, urging clarity about the term “carbon debt”:

This is atmospheric carbon generated by the expansion of agriculture throughout the world to meet increased demand (for food, feed and fiber as well as biofuels) and to take advantage of higher prices for agricultural production.”

Though the letter was not printed in Science, the authors did send a formal response, noting first that “meeting new demand does not necessarily mean that large carbon debts are inevitable” and further:

We also know that carbon debt can be minimized or avoided if we can increase crop yields on lands already being used for agriculture (including degraded pastures) or on abandoned agricultural lands if we employ innovative management techniques, including the use of advanced biotechnology. A number of researchable questions about carbon debt remain to be answered. Our primary argument is that we should take the time and care to get it right from the start, and pay attention to early indications of environmental regret and synergy.”

The Food Before Fuel Coalition in mid-February issued a list of principles for further development of biofuels, including:

Proceed with caution by engaging in serious and practical research on 'advanced biofuels' to ensure we avoid the same kind of 'unintended consequences' that have resulted from the push to expand production of corn ethanol.”

Members of that coalition, the Worldwatch Institute and the Sierra Club, also issued a report, Smart Choices for Biofuels, saying in a press release:

The steps proposed in the report include an accelerated transition to cellulosic feedstocks such as switchgrass and the use of more effective agricultural practices to decrease erosion and soil nutrient depletion.”

A post by John Guerrerio of the Examiner takes a look at the proposal by the Sierra Club and Worldwatch:

The claims made by the Sierra Club and the Worldwatch Institute in their report are widely seen as valid. They are, however, part of a process that may be used to delay biofuel production and ultimately drive the final nail into the coffin of a dying industry."

Though environmental groups profess support for cellulosic and advanced biofuels, the continued expansion of the definition of “indirect land use change” appears to constitute a divide and conquer strategy – undermine support for conventional ethanol, and then let cellulosic biofuels fall by themselves.

Indirect land use change continues to be a moving target with no clear definition and no direct evidence to support it.