From: , Science and Development Network, More from this Affiliate
Published February 18, 2008 09:17 AM

http://www.enn.com/top_stories/article/31344 

Two studies have shown that changes in land use to produce crop-based biofuels can actually result in more greenhouse-gasemissions than burning fossil fuels.

The studies, both published in Science last week (8 February), estimate the impact of converting forests and grasslands into cropland for the production of biofuels.

Both conclude that the resulting carbon emissions, released through decomposition or burning of biomass, create a 'carbon debt' that takes decades or even centuries to be paid back through biofuel usage.

This finding undermines previous claims that substituting fossil fuels with biofuels should offset greenhouse-gas emissions because biofuels sequester carbon while they grow.

According to Timothy Searchinger, researcher at Princeton University and the lead author of one of the studies, previous assessments did not include the carbon storage and sequestration sacrificed when diverting land from its existing use.