The question is whether crops belong in your mouth or your gastank? Bioscience has a interesting article from June with National Geographic following on their heals this month. Both are very interesting and worth the read. Nash in Bioscience lays out what are the potential ill effects of moving to biofuels:
- Diversion of food crops such as corn and soybeans into gas tanks
- Release of greenhouse gases
- Conversion of wildlife habitat into energy-crop farmland
- Accelerating soil depletion
- Drawdown of scarce water resources for irrigation
- Spread of invasive species used as energy crops
- Illusion of sustainability despite extravagant energy consumption
- More use of groundwater-polluting pesticides, herbicides, and fertilizers
This quote really caught my eye.
If the whole of the current US soybean and corn crops were diverted to biofuel production, they would satisfy only about 6 percent of the demand for diesel and 12 percent of the demand for gasoline.
The rest of the article finishes with interesting insights about new methodologies like cellulosic ethanol that would allow any plant material, including garbage, paper, sawdust, etc. to be refined into ethanol and the work by Tilman suggesting that restored prairies could be harvested for biofuels.
…Tilman and collaborators linked his earlier research on prairie perennial grasses to cellulosic ethanol. It makes the prairie ecosystem look like a near-miracle: a source of nonfood energy and wildlife habitat that sharply diminishes greenhouse gas emissions; avoids irrigation, as well as pesticide, herbicide, and fertilizer pollutants; and provides resistance to invasives…If they were grown on the degraded soils set aside under federal conservation programs, they wouldn’t even displace food crops. And, the study concluded, they would produce a net energy gain per hectare 50 percent greater than corn grain ethanol from prime soils. “A first step,” Tilman says,”would be allowing farmers to mow their current Conservation Reserve Program grassland for the energy in its hay, and there’s 35 million or so acres of that land.” It could be seeded with prairie species that would be dominant within five years. During the first decade, they build up an immense carbon-sequestering root system. Root growth levels off, but the soil continues to sequester carbon for about a century. Because few or no resource and energy inputs are needed to prod growth, the study’s LCA balance sheets make prairie-grass ethanol look like a bargain compared with other waste-based biomass sources, such as cornstalks.