February 13, 2008
Trendy climate-change policies like ethanol and other biofuels are actually worse for the environment than fossil fuels, according to two studies published in Science, a peer-reviewed journal.
The first study, by ecologists at Princeton University and the Woods Hole Research Center, break new ground by exposing a kind of mega-accounting error:
- Prior studies had never credited the carbon-dioxide emissions that arise when virgin forests, grasslands and the like are cleared to grow biofuel feedstocks.
- About 2.7 times more carbon is stored in terrestrial soils and plant material than in the atmosphere, and this carbon is released when these areas are cleared (often by burning) and the soil is tilled.
- Compounding problems is the loss of "carbon sinks" that absorb atmospheric CO2 in the bargain.
- Previous projections had also ignored the second-order effects of transferring normal farm land to biofuels, which exerts world-wide pressure on land use.
- When the hidden costs of conversion are included, greenhouse-gas emissions from corn ethanol over the next 30 years will be twice as high as from regular gasoline.
- In the long term, it will take 167 years before the reduction in carbon emissions from using ethanol "pays back" the carbon released by land-use change.
The second study comes from the University of Minnesota and the Nature Conservancy, and explores what the authors call the "carbon debt," when native ecosystems are converted to biofuel stock. Until the debt is repaid, biofuels from those fields will be greater net emitters than the fossil fuels they replace:
- The authors find that the debt for corn ethanol in the United States is between 48 and 93 years.
- In Indonesia and Malaysia, which have a 1.5 percent annual rate of deforestation to produce palm oil for Western European biodiesel, the debt is as high as 423 years.
Source: Editorial, "Greenhouse Affect," Wall Street Journal, February 13, 2008.
For Princeton University and Woods Hole Research Center study:
For University of Minnesota and the Nature Conservancy study:
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