Why would renewable bioenergy not be climate neutral? Are studies that have questioned the carbon neutrality of bioenergy based on some sort of sleight of hand or an alternative truth to natural science? Let’s think about it.
When talking of the climate effects of bioenergy, the crux of the matter is summed up in the word “effect”. According to the general understanding of causality, an effect is always the result of a cause. Therefore, the climate effects of bioenergy are caused by the use of bioenergy. However, the causality, or the relationship of cause and effect of any one matter, cannot, as such, be determined from the observed or presumed state of the matter. Consequently, the climate effects of bioenergy are not caused by any scientifically measured carbon flows that are realised when bioenergy is used. Instead, the effects are caused by the discrepancy between two realities: that in which bioenergy is used, and in which it is not used.
In assessing the climate effects of bioenergy, there is no need for an alternative truth to natural science. Instead, the description of an alternative reality for bioenergy is crucial. There may be numerous variables between these mutually alternative realities or scenarios. According to most studies, the most important of these are related to how the production of bioenergy changes the carbon storages of terrestrial ecosystems and the use of fossil fuels. The methods of natural science are not alone sufficient to describe these scenarios, and must be aided by a multidisciplinary approach that combines the understanding of natural sciences, engineering, economics and social sciences in the most useful possible way.
As a discipline, the assessment of the climate effects of bioenergy is connected to industrial ecology, while its methodology does well to lend from the principles of life cycle assessment. The results of the assessment are inevitably founded on presumptions that may be more or less consistent and reliable. The same applies for conclusions formed by interpreting the results of the assessment. In my three-year research project funded by the Kone Foundation, my aim is to investigate the significance of these factors on the conclusions reached in studies on the climate effects of the use of forest resources.
Bioenergy is not neutral in terms of its effects on climate. On the contrary, the climate effects of bioenergy may be relatively high for several decades if production results in the significant reduction of carbon storages in terrestrial ecosystems, or if the replacement of fossil fuels remain at a low level. Increase of the use of biomass in energy production is further restricted by its limited availability and by concerns related to the preservation of biodiversity, security of food supply, and urgency of mitigating climate change. The question, then, is where this line should be drawn.
Sampo Soimakallio, D.Sc. (Tech.) is the Head of the Sustainable Use of Natural Resources Unit at the Finnish Environment Institute. He also holds the title of Docent at the University of Helsinki.