Next gen biofuels could decimate rainforests
Next gen biofuels could decimate rainforests
mongabay.com
May 27, 2008
Next generation biofuels could decimate tropical forests says a leading ecologist from the University of Minnesota.
Speaking at Stanford University on May 15, Dr. David Tilman said cellulosic ethanol technologies that convert biomass directly into biofuels could put new pressure on forest lands already bearing the brunt of agricultural expansion in the tropics. He estimated that a typical hectare of rainforest with 200 tons of harvestable biomass could yield 15,000 gallons of ethanol once cellulosic technology is commercial. In dollar terms, clear-cutting rainforest for ethanol production could generate more than $36,000 in revenue per hectare and perhaps $7,000 in profit. A million-hectare lot could generate $7 billion in profit.
In other words, cellulosic conversion technology could easily drive deforestation, especially in the tropics where converting natural systems to fuel would be easier than planting potential fuel-crops like oil palm, sugar cane, soybeans, or corn.
 Chart modified from Science. Tilman was co-author of a study published in February 2007 that showed the production of some biofuels can result in emissions greater than those from fossil fuels. The analysis looked at the lifecycle emissions from various biofuel feedstocks and presented the results as a “carbon debt” ranking. |
Still Tilman is hopeful that cellulosic technology can be used in ways that reduce the need to convert sensitive ecosystems and generate fuels from feedstocks that are not used for food. Specifically, Tilman believes use of native species — especially perennial grasses and shrubs — could improve the yields and sustainabilty of biofuel production.
Based on a decade of research at the Cedar Creek Natural History Area, a 2200-hectare experimental ecological reserve operated by the University of Minnesota, Tilman said that diverse mixtures of plants that mimic the native prairie ecosystem are a better source of biofuels than corn ethanol or soybean biodiesel.
“High diversity grasslands produced 238 percent more biofuels than monocultures,” Tilman said, adding that highly diverse system also sequester carbon from the atmosphere and require fewer agricultural inputs (water, fertilizer, and pesticides) than low diversity systems like monocultures.
“Biofuels made from high-diversity mixtures of prairie plants can reduce global warming by removing carbon dioxide from the atmosphere. Even when grown on infertile soils, they can provide a substantial portion of global energy needs, and leave fertile land for food production,” said Tilman.
The global food crisis
Tilman also spoke about the global food crisis, offering several “rules of thumb” to ensure that food production meets the needs of future generations.
He said that fertile lands should be used for food, not biofuels, and argued that the world needs to sustain at least linear gains in crop yields by investing in crop breeding and the development of new crops and varieties. In poor countries, technology transfer and improvements in infrastructure and farming techniques could boost productivity and help make small farmers more self-sufficient. Wealthy governments should facilitate the effort by funding research for crop improvements in crops that “are not sufficiently profitable” for seed companies and the private sector, he said. Finally, encouraging dietary shifts away from resource-intensive foods like beef and pork could further reduce the global land footprint for agriculture.
“With forethought, we can secure the food supply, energy, and livable environments that future generations deserve,” he said.
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