USING biofuels instead of fossil fuels will do little to cut carbon emissions, and could even increase them because of the extra land the crops will require.
Joseph Fargione of The Nature Conservancy in Minneapolis, Minnesota, and colleagues looked at the “carbon debt” that will accrue if land is cleared to grow biofuel crops. This leads to carbon being released, initially when forests are felled or bush is cleared, and in the longer term when dead roots decay.
They found that for every 10,000 square metres of Brazilian rainforest cleared for growing soya to make biodiesel, over 700 tonnes of…
