Science magazine this week published an exchange between Vinod Khosla, the venture capitalist who has invested a great deal in alternative energy, and Timothy Searchinger and coauthor Richard Houghton critiquing and defending the February 2008 study, “Use of U.S. Croplands for Biofuels Increases Greenhouse Gases Through Emissions from Land-Use Change” The exchange reveals some of the nuances of indirect land use change arguments that have not been addressed.
Khosla’s comments raise two important issues, allocation and system boundaries, though they go largely unexplored. He writes,
It is inaccurate and misleading to allocate the cutting down of Brazilian rainforest, which is done often for timber production, to biofuels use. The economic signals driving biofuels or agricultural land-use changes are different from the timber-driven economic signals driving land-use change patterns. The deforestation estimates of Searchinger et al. are appropriate for biodiesel production in the Far East.”
Deforestation in Malaysia can be allocated appropriately to biodiesel production, in Khosla’s view, because ecologically sensitive land has been converted to palm oil plantations in part to meet demand for biodiesel. The system boundaries of that supply and demand dynamic are clear. Moving from U.S. biofuel policy, which emphasizes domestic production of biofuel over imports, to deforestation in Brazil is a broader system where responsibility must be allocated more carefully, taking into account the direct causes of deforestation such as Brazilian policy.
In their response, Searchinger and Houghton avoid the problem of allocation and instead raise a moral issue:
Biofuels that use good cropland anywhere in the world raise crop and meat prices and help spur the actual conversion to pasture or cropland by increasing their net economic return.”
The sentence does little to support the theory that U.S. biofuel production is tied indirectly to deforestation in Brazil. What it does is seek to set the system boundary for biofuel production at a worldwide level. In order to examine the effects of U.S. biofuel production in this system, all causes of increased crop and meat prices, as well as all policies to encourage or discourage deforestation, must be taken into account and allocated properly.
Searchinger and Houghton further reveal the moralistic tone of their argument in another part of their response:
Khosla correctly notes the capacity to boost yields in many developing countries, but the world must already unleash that capacity to feed a larger, selectively richer, world population while also reducing deforestation.”
This reminds me of when my mother told me as a child to clean my plate because there were starving children in Bangladesh. It’s a snarky comment, I know, but Searchinger and Houghton are attempting to argue that an interdependent worldwide market for food, land and carbon emissions already exists and can be modeled according to economic equilibrium principles. They need to present more evidence and avoid moral arguments.