Growing palm oil trees to make biofuels could be accelerating the effects of climate change, new research shows, adding further weight to claims the crop is not environmentally sustainable.
In a paper published in the journal Nature, an international team of scientists examined how the deforestation of peat swamps in Malaysia to make way for palm oil trees is releasing carbon which has been locked away for thousands of years.
Microbes then penetrate the carbon and the harmful greenhouse gas carbon dioxide is released, which is thought to be the biggest contributor to global warming.
Unsustainable methods of growing crop-based biofuels have come under fire as environmentalists question the emissions savings they make, the agricultural land they occupy and whether the growth of certain crops contribute to deforestation.
More than 80 per cent of palm oil is grown in Indonesia and Malaysia.
According to some estimates, an area the size of Greece is cleared every year for palm oil plantations.
As governments and companies look to biofuels to provide a low-carbon alternative to fossil fuels in transport, the industry has expanded rapidly.
Palm oil is especially attractive because it is cheaper than rapeseed oil and soybean oil for biodiesel.
However, leaked European Union data has shown palm oil biodiesel to be more polluting than conventional gasoline when the effects of deforestation and peatlands degradation is taken into account.
In their study, the research team measured water channels in palm oil plantations in the Malaysian peninsular which were originally peatland swamp forest.
They found ancient carbon came from deep in the soil, then broke down and dissolved into nearby streams and rivers as deforestation occurred.
"We have known for some time that in South East Asia oil palm plantations were a major threat to biodiversity (..) and that the drainage could release huge amounts of carbon dioxide during the fires seen there in recent years," said Chris Freeman, one of the authors of the report and an environmental scientist at the University of Bangor in Wales.
"But this discovery of a 'hidden' new source of problems in the waters draining these peatlands is a reminder that these fragile ecosystems really are in need of conservation," he added.
There are approximately 28,000 sq km of industrial plantations in Malaysia, Sumatra and Borneo and there are even more planned, making them a major contributor to peat swamp deforestation in the region, the paper said.
"Our results are yet another reminder that when we disturb intact peat swamps and convert them to industrial biofuel plantations, we risk adding to the very problem that we are trying to solve," said Freeman.
The research team included scientists from the British universities of Leicester and Bangor, the Met Office Hadley Centre, the Natural Environment Research Council Radiocarbon Facility in Scotland, the University of Palangka Raya in Indonesia and water research institute Deltares in the Netherlands.
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