Biofuels, considered a sustainable alternative to depleting energy resources, can lead to an increase in greenhouse gas emissions, suggest two studies published in the journal Science

Two studies published recently in the journal Science have found that biofuels can actually produce more carbon dioxide emissions than they save, if they force natural habitats to be converted to cropland, releasing the carbon contained in trees and grasses and in the soil they grow on.

On the other hand, ‘biofuels made from waste biomass or from biomass grown on abandoned agricultural lands planted with perennials incur little or no carbon debt and offer immediate and sustained GHG advantages,’ the studies say.

One study was produced by a team of researchers at the University of Minnesota, and the other was led by researchers from Princeton University.

Both reports conclude that it is not a good idea to clear forests, peatland and grasslands for biofuel crops because these are nature’s premier methods of carbon capture. The world’s forests and grasslands contain an enormous reservoir of carbon, which would add to greenhouse warming if released into the atmosphere. Even switchgrass, if grown on land now being grown to produce corn, could increase emissions by 50% if it forces the clearing of new land to grow food.

The studies have created a furore in scientific circles and, according to a report in the Washington Post, senior scientists have responded to the new studies by sending a letter to US President George Bush and House Speaker Nancy Pelosi urging them to reconsider their energy policies.

‘While politicians in the US and Europe have tried to craft policies dictating that new biofuels will not come at the expense of clearing land, the papers show that sometimes land conversion is often an indirect result of this expansion,’ the 10 scientists wrote. ‘There is an urgent need for policy that ensures biofuels are not produced on productive forest, grassland or cropland.’

Meanwhile, Worldwatch Institute, an environmental research organisation based in Washington DC, has recommended that tax subsidies for food-based biofuels be reduced and subsidies for fuels with a low carbon footprint, such as waste and cellulose-derived biofuels, should be increased.

Writing on the Worldwatch website, Christopher Flavin, President of the Worldwatch Institute, said that what the new studies seem to be suggesting is that ‘the current world agricultural system, like the world energy system, is unsustainable. And unless it’s fixed, rising production of both fuels and food will wreak havoc’.

Source: Worldwatch Institute, February 13, 2008