Nov 4, 2011
Biofuels made from vegetable oils are as bad as fossil fuels when it comes to carbon emissions, a study says.
Researchers at Leicester University have found that emissions associated with palm oil plantations are 50 per cent worse than previously thought because the land releases carbon that was previously trapped in peat for thousands or even millions of years.
Producing biofuels from other vegetable oils such as rapeseed and soya also has high associated emissions because using them for fuel indirectly leads to an increase in palm oil farming to meet demand for cooking oil.
‘A tropical forest contains a lot of carbon in its biomass, so to grow the oil palm you need to chop the forest down and replace it with something that stores less carbon,’ Ross Morrison, one of the study’s authors, told The Engineer.
‘So there’s a loss of carbon when you deforest but the largest loss is from the old carbon being released. The only reason the peat is stable is because it’s waterlogged all the time. Once you drain it you allow oxygen into the peat and this causes very rapid microbial decomposition and that releases CO2.’
Biofuels are typically thought of as having low net greenhouse gas emissions because when they are burnt they release carbon dioxide only recently captured from the atmosphere. Previous estimates put their associated emissions at 50 tonnes of CO2 per hectare per year.
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