Not long ago biofuels were seen as one of the major tools to combat climate change, but a large number of studies in recent years have shown that many first generation biofuels may have little climate benefit—and some are actually harmful—and are also linked to rising food prices. Now, a new study in Nature Climate Change warns that biofuels using fast-growing trees (polar, willow, and eucalytpus) could also exacerbate ground-level ozone pollution.
“Concerns about climate change and energy security are driving an aggressive expansion of bioenergy crop production and many of these plant species emit more isoprene than the traditional crops they are replacing,” the paper states.
Isoprene is a precursor to ozone, which as a ground-level pollutant is believed to cause many health-problems especially among the vulnerable, including premature death. The compound is produced by a number of species of trees, including those most likely to be grown en masse for bioenergy. The paper estimates that growing trees on 72 million hectares of land in Europe could result in 1,400 premature deaths on the continent annually at a cost of $7.1B. Currently, 22,000 people are estimated to die prematurely from ozone pollution in Europe every year. Ground-level ozone also reduces crop yields.
“The extent to which these crops will be grown is still a subject of much debate. Using all the land available (72 million hectare) must be seen as an extreme case, especially when food security is a priority,” Keith Goulding with Rothamsted Research said in response to the paper.
While planting trees for bioenergy would no doubt lead to an uptick in ozone pollution, it should be noted that burning fossil fuels—coal, oil, and gas—is generally seen as a larger and graver contributor to air pollution than tree plantations.
When asked about how potential isoprene pollution would compare to offsetting burning some fossil fuels, the study’s co-author, Nick Hewitt, told the Guardian, “We’re not in a position to make that comparison.”
The researchers do suggest that ozone pollution could possibly be mitigated through genetic engineering or growing the plantations in areas where the pollution wouldn’t have a significant impact.
In the end, research like this helps experts weigh the best option for biofuels, according to Ottoline Leyser, Director of the Sainsbury Laboratory at Cambridge.
“There are many different biofuel crops, cultivation methods, production and processing systems post-harvest, and different final biofuels. Each one has advantages and disadvantages, which must be compared to the advantages and disadvantages of alternative options,” he notes.
CITATION: K. Ashworth, O.Wild and C. N. Hewitt. Impacts of biofuel cultivation on mortality and
crop yields. Nature Climate Change. 2013.
(11/28/2012) The European Commission has approved palm oil-based biodiesel for the renewable fuels standard provided it is certified under the Roundtable for Sustainable Palm Oil (RSPO), a body that sets social and environmental criteria for palm oil production. The move, which could dramatically boost sales of palm oil in Europe, was sharply criticized by environmental activists, who said that without stronger safeguards, increased palm oil production could increase deforestation and greenhouse gas emissions.
(09/13/2012) The European Union may cap the use of crop-based biofuels over fears they can drive up food prices and aren’t effective in reducing greenhouse gas emissions relative to conventional fuels, reports Reuters.
(05/18/2012) The palm oil industry has hired lobbying powerhouse Holland & Knight to help overturn the Environmental Protection Agency’s finding that palm oil-based biodiesel fails to meet greenhouse gas emissions targets under the country’s Renewable Fuels Standard, reports The Hill.
(05/14/2012) Carbon emissions from deforestation vary greatly depending on whether timber stocks are turned into finished wood products, converted into bioenergy feedstocks, or burned outright, reports a new study published in Nature Climate Change.
(04/26/2012) Wilmar International, the world’s largest palm oil processor and trader, has hired a major lobbying firm to overturn the Environmental Protection Agency’s ruling that palm oil-based biodiesel will not meet greenhouse gas emissions standards under America’s Renewable Fuels Standard, reports The Hill.