Bad news for international bio-energy regulators
A team of scientists has found that bio-energy crops such as oil palm can ‘swing’ the balance of their greenhouse-gas emissions depending on how the crop is managed. International regulators concerned with reducing emissions will have to look to the managers if they want to achieve their goals
The greenhouse-gas balance of bio-energy can swing from positive to negative or vice versa depending on key management decisions such as what the land was used for before the crop was planted, how the crop is harvested, when it is harvested and the way it is fertilized.
‘We found that the largest “swing potential” was with oil palm: it all depends on where and how it is grown’, said Dr Sarah Davis, leader of the team of researchers from eight different institutions.
‘This in itself is a major challenge for the regulators of bio-energy. It would be much easier for them if the products of oil palm could be used as indicators of the environmental consequences of the crop. However, it doesn’t seem to be that easy. They will have to take into account human decisions and practices in the crop’s management’.
These high-yielding bio-energy crops such as corn or maize, sugarcane, Miscanthus grass and fast-growing tree species can be managed for greenhouse-gas benefits or losses, suggesting that the bio-energy sector should incorporate evaluation of management techniques into classifications of bio-energy feedstock.
‘The environmentally best and worst palm oil look the same’, added Dr Meine van Noordwijk, one of the researchers.
‘The “swing potential” thus contains both good news—the same product can be obtained from cleaner modes of production—and bad (for regulators): rules need to allow differentiation according to origin and some form of certification of production conditions’.
Bio-energy crops are often classified, and subsequently regulated, according to species that have been evaluated as environmentally beneficial or detrimental but the researchers have shown that, in practice, management decisions rather than species per se can determine the overall environmental impact of a bio-energy production system.
However, while the management swing potential is substantial for many cropping systems, there are some species, such as soybean, that have such low bio-energy yield potential that the environmental impact is unlikely to be reversed by management.
In their study, the researchers reviewed seven different bio-energy cropping systems in temperate and tropical regions.
Bio-energy regulators and managers would be well advised to read the study closely.
Read the research report
The research team
The research team was made up of scientists from Energy Biosciences Institute, University of Illinois, Urbana, USA; EMBRAPA Agrobiologia, Rio de Janeiro, Brazil; Rural Climate Solutions, University of New England and New South Wales Department of Primary Industries, Australia; Natural Resource Ecology Laboratory, Colorado State University, Fort Collins, USA; Institute of Biological and Environmental Sciences, University of Aberdeen, UK; World Agroforestry Centre, Bogor, Indonesia; Wageningen University, The Netherlands; International Livestock Research Institute, Nairobi, Kenya.