The debate over the ‘greenness’ of biofuels is gathering pace as critics allege that their development is raising food prices and harming the environment. Advocates point to the importance of the substitute for fossil fuels as oil prices reach record levels and ‘peak oil’ production may have been passed.
However, the critics are using their voice, including Nobel Prize winner Paul Crutzen who in a report says that biofuels production speeds up global warming through the use of industrial farming methods that use fertilisers that can produce nitrous oxide, which is 300 times more insulating than carbon dioxide. Biodiesel derived from rapeseed could produce up to 1.7 times more greenhouse gas than conventional diesel the report, Atmospheric chemistry and physics discussions, claims.
Other critics point to damage to the quality and quantity of water supply in the US. The committee of the US National Research Council found that in terms of quantity, agricultural shifts to growing corn and other biofuels crops in regions that currently have little agriculture could greatly increase pressure on water resources in many parts of the US.
SRI Consulting (SRIC) suggests in its Carbon footprint of biofuels and petrofuels report that, from a global warming viewpoint at least, farmers in Northern Europe should plant trees and burn petrodiesel rather than plant rapeseed for biodiesel. Conversely, it says that greenhouse gas emissions are reduced by converting a Malaysian rain forest into a palm oil plantation rather than filling tanks with petrodiesel.
Mike Arné, assistant director of SRIC’s greenhouse gases initiative said: ‘Generally speaking, where a crop is grown plays a more important role in the biofuel/petrofuel footprint than what type of crop is grown… If rapeseed were grown on former US prairie land normally devoted to corn and soybeans, the choice between petro and bio becomes a tie.’
The difference highlighted above for the same crop but with alternative land uses in the US and Europe, is due to the difference in land carbon capacity. A forest can store tremendously more carbon than can a prairie, the report says.
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