Biofuel production to pollute environment, says study

Ironically, converting new land to produce alternative fuels from crops and grasses can cause emissions of carbon dioxide 420 times more than the annual savings from replacing fossil fuels, according to Minnesota-based scientists.

Policymakers in the European Union and the US have identified biofuels as a tool to fight global warming, as they emit less greenhouse gases than burning fossil fuels.

The US recently enacted legislation boosting biofuel production to 36 billion gallons in 2022 from 7.5 billion gallons in 2012. EU requires 10 per cent of the transportation to use biofuels by 2020.

Converting forests and peatlands that absorb carbon dioxide from the atmosphere to grow the crops may cause emissions that may far outweigh the annual benefits of burning the new fuels, creating a "carbon debt" lasting centuries, the researchers at the University of Minnesota, St Paul and the Minneapolis-based Nature Conservancy said in the journal Science.

"If you're trying to mitigate global warming, it simply does not make sense to convert land for biofuels production,'' lead author Joe Fargione said in a statement. "All the biofuels we use now cause habitat destruction, either directly or indirectly.''

The scientists studied different cases of natural habitat conversion, and used data from previous studies to determine the carbon debt accrued.

They found that converting Indonesian or Malaysian peatlands into palm plantations incurred a carbon debt that took 423 years to neutralise. Replacing tropical rainforests in those two nations with the same crop led to an 86-year debt.

US crops
US biofuels can also lead to a debt lasting decades, the scientists found. When corn for ethanol is planted on grassland, it takes 93 years for the benefits to set in, while placing the same crops on abandoned agricultural land led to a 48-year lag.

In Brazil, the benefits from converting savanna grassland to cultivate soybeans took 37 years to set in, while replacing wooded savanna with sugarcane led to a 17-year lag. When rainforest is felled to grow soybean, a 319-year debt is incurred, they said.

Not all biofuels led to significant carbon debts. Allowing prairie grasses to grow on abandoned or fertile cropland led to a debt lasting as long as a year, according to the study.

"In finding solutions to climate change, we must ensure that the cure is not worse than the disease,'' Jimmie Powell, leader of The Nature Conservancy's energy team, said in the statement. "These findings should be incorporated into carbon emissions policy going forward.''

'Harmful' targets
The scientists are the latest to question the value of cultivating some biofuels to fight climate change, which United Nations scientists have said will cause floods and droughts to occur more regularly and storms to intensify, displacing millions of people.

The UK's national science academy, the Royal Society, said January 14 that UK efforts to boost biofuel usage may not lead to significant reductions in greenhouse gases because of the changes in land-use associated with cultivation of the crops.

A cross-party parliamentary panel of UK lawmakers on January 21 said the UK and EU should scrap their "harmful'' biofuels targets.

In a separate study also published online in Science yesterday, a team led by Timothy Searchinger, a research fellow at Princeton University in New Jersey, found that fuelling vehicles with ethanol made from corn or switchgrass causes more environmental harm than fossil fuels.

Searchinger's team determined that corn-based ethanol almost doubles greenhouse-gas output over 30 years when considering land-use changes to grow corn.

Cellulosic ethanol made in the US from switchgrass, a fuel identified by President George W Bush as a way to reduce the country's dependence on oil, produces 50 per cent more emissions than gasoline, the study said. A group representing members of the biofuels industry disputed the findings of the two studies.

Industry response
"Increasing the availability and use of low-carbon fuels will bring immediate and long-term environmental benefits by lowering greenhouse-gas emissions and encouraging sustainable agricultural practices that provide greater efficiencies and lower costs,'' Brent Erickson, vice president of the Biotechnology Industry Organization, said in a statement.

Searchinger's model projects greenhouse-gas emissions will grow with ethanol demand. US farmers will convert their cropland to grow fuel, which increases food commodity prices. That, in turn, causes rainforests and other undeveloped areas to be levelled and cultivated, the study said.