Indirect land-use change
The cultivation of energy crops such as wheat, rapeseed, sugar cane or oil palm requires land. It competes with nature. Grasslands or forests are converted into arable land. Such conversion leads to loss of biodiversity. Furthermore, much of the carbon stored in natural vegetation and soil is released into the air as CO2. The EU sustainability criteria prevent this direct land-use change from taking place. However, when arable land used for growing energy crops was used for the cultivation of food crops before, there is no direct land-use change. These displaced food crops have to be produced elsewhere, which does lead to indirect land-use change, and thus to similar negative effects. Currently, the European Commission is studying criteria to deal with these ILUC effects.
Agricultural intensification as a potential solution
An alternative to indirect land-use change from displaced food crop production would be an increase in yields on existing agricultural land. This would require better agricultural management, based on more knowledge and means, especially in developing countries. Therefore, the indirect impact from biofuels is strongly related to global agricultural practices. One of the measures that could increase yields is an increase in the use of fertiliser. However, if using more fertiliser (especially nitrogen) would be the only measure, then this could result in an increase in greenhouse gas emissions of the same order of magnitude. Therefore, it would also be essential to improve the efficiency of fertiliser use.
Uncertainties about indirect effects
It is not easy to determine the actual indirect effects from biofuel use exactly. These impacts cannot be monitored directly and calculations are quite complicated. One of the complicating issues are the by-products, especially feed. Energy crops such as rapeseed or wheat provide feed as well as biofuel. This feed could replace feed production elsewhere, leading to a possible reduction in indirect land-use change. New products on the energy and feed markets, inducing not easily predictable changes in prices, lead to several other cause-effect chains in the global system as well. Next to indirect land use change, changes may also occur in energy and meat consumption. Integral models can be a supportive tool to assess these effects, but because of the large number of model assumptions they would provide a range of results
A complicating factor in the introduction of an ILUC emission factor as a sustainability criterion for biofuels is that the indirect emissions follow from the interaction between biofuels and the global system, and are not a characteristic of biofuel itself.
Preventing biodiversity losses often is the goal of sustainability criteria. Excluding direct use of natural land is a way to do so, but indirect land-use change cannot always be prevented. Actual indirect impact on biodiversity is the result of a combination of factors. For the two main factors related to biofuels, land-use change and greenhouse gas emissions, a quantitative approach is used based on ‘naturalness’, an indicator which represents one of the aspects of biodiversity. In the case of net emission reductions in the long term, the negative climate effect would be reduced. This would have to compensate for short-term loss from indirect land-use change, and this compensation may take hundreds of years. Additional agricultural intensification or the use of land with a low biodiversity, would reduce this period, significantly.
The Netherlands Environmental Assessment Agency (PBL) published a series of five brief reports on the issue of indirect effects of bio-energy. The series includes a survey on indirect effects, an assessment of the impact of feed by-products, the role of global agricultural intensification, a quantitative analysis of the impact on global biodiversity, and of the suitability of integral models for the calculation of ILUC factors.
- The contribution of by-products to the sustainability of biofuels
- Indirect effects of biofuels: intensification of agricultural production
- Are models suitable for determining ILUC factors?
- Evaluation of the indirect effects of biofuel production on biodiversity: assessment across spatial and temporal scales