Next gen biofuels could decimate rainforests
May 27, 2008
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.
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.
Cellulosic energy may trigger dramatic collapse in the Amazon March 11, 2008
Next generation biofuels may trigger the ecological collapse of the Amazon frontier and could have profoundly unexpected economic consequences for the region, warns a paper published in Philosophical Transactions of the Royal Society B. Dr. Donald Sawyer, an associate professor at the Center for Sustainable Development at the University of Brasilia and an associate researcher at the Instituto Sociedade, População e Natureza, writes that "interacting with climate change and land use, the upcoming stage of cellulosic energy could result in a collapse of the new frontier into vast degraded pasture." The shift could increase the incidence and severity of fires, reduce rainfall in key agricultural zones, exacerbate forest die-back and climate change, and worsen social instability.
Biofuels are worsening global warming February 7, 2008
Converting native ecosystems for production of biofuel feed stocks is worsening the greenhouse gas emissions they are intended to mitigate, reports a pair of studies published in the journal Science. The studies follow a series of reports that have linked ethanol and biodiesel production to increased carbon dioxide emissions, destruction of biodiverse forest and savanna habitats, and air and water pollution.
Carbon-negative bioenergy to cut global warming could drive deforestation November 6, 2007
A proposed mechanism for generating carbon-negative bioenergy -- an energy source that reduces atmospheric carbon dioxide levels -- could drive large-scale deforestation in the tropics and undermine efforts to conserve forests for carbon offsets says a biofuel expert.
Biomimicry of native prairie yields more bioenergy than corn ethanol December 7, 2006
Diverse mixtures of plants that mimic the native prairie ecosystem are a better source of biofuels than corn grain ethanol or soybean biodiesel according to a new paper published in the Dec. 8 issue of the journal Science. Led by David Tilman, a biology professor at the University of Minnesota, the research shows that "mixtures of native perennial grasses and other flowering plants provide more usable energy per acre than corn grain ethanol or soybean biodiesel and are far better for the environment," according to a release from the University of Minnesota.
Cellulosic ethanol fuels environmental concerns August 6, 2006
In recent months, high fuel prices and national security concerns have sparked interest in biofuels. Cellulosic ethanol, which can be derived from virtually any plant matter including farm waste, looks particularly promising. The U.S. Department of Energy projects that cellulosic conversion technology could reduce the cost of producing ethanol by as much as 60 cents per gallon by 2015. Green groups see cellulosic ethanol as a carbon neutral energy source that could be used to fight the build up of atmospheric carbon dioxide responsible for global warming.