January 6, 2013

expert reaction to the impacts of biofuel cultivation on human health and crop yields

Findings published in Nature Climate Change suggest large-scale cultivation of biofuels in Europe could lead to increased human mortality and crop losses. 

Prof Ottoline Leyser, Director of the Sainsbury Laboratory, University of Cambridge, said:

“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. The key is to ensure that the policies driving biofuel development and adoption are properly formulated to take account of these complexities, as described in the 2011 report of the Nuffield Council on Bioethics.”

Dr. Angela Karp, Scientific Director of the Cropping Carbon Institute Programme, Rothamsted Research, said:

“It is well known that many trees emit isoprene and efforts have been placed on reducing this. In our own Institute Strategic Programme grant (Cropping Carbon) we have flagged this up as a target for research, pointing out that reducing isoprene emissions from willow would not only reduce greenhouse gases but reduce loss of carbon from the plant. Having said that, at least one previous publication I know of does not suggest that the levels harm air quality.

“Land use calculations of impacts for willows and poplars need to consider that they are among many biofuels crops being grown (most of which are not trees but grasses) and take into consideration the large land areas already under forests. For all these reasons we do not see that the UK needs to reconsider its interest in biofuels.”

Prof Keith Goulding, Head of the Department of Sustainable Soils and Grassland Systems, Rothamsted Research, said:

“Ground-level ozone results from emissions of NOx and Non-Methane Volatile Organic Compounds (NMVOCs), the latter from trees and other higher plants. This research says that increasing the area of bioenergy crops will increase NMVOC emissions and so ground-level ozone, and makes a valuable contribution to our understanding of the impact of bioenergy crops. However, the extent to which these crops will be grown is still a subject of much debate. Using all the land available (72Mha) must be seen as an extreme case, especially when food security is a priority.”

“Current issues with ground level ozone are summarised well in the recently (2012) published Review of Transboundary Air Pollution (RoTAP): http://www.rotap.ceh.ac.uk/ which states that ‘exposure to typical summer concentrations of ozone has been calculated to reduce the UK yield of wheat and potato production by 7% and 2% respectively’. And goes on to say that ‘for ground level ozone, the benefits of reductions in peak values as a consequence of reductions in European emissions of oxidised nitrogen and volatile organic compounds, have been eroded substantially by emissions elsewhere throughout the northern hemisphere, including from international shipping, which are driving up the background ozone concentrations. To solve ground level ozone problems in the UK and elsewhere, it will be necessary to develop policies and emission control measures at the hemispheric scale.’”

‘Impacts of biofuel cultivation on mortality and crop yields’ by K. Ashworth et al., published in Nature Climate Change on Sunday 6th January.