Biocharred pathways to sustainability? Triple wins, livelihoods and the politics of technological promise

Considerable hype and debate are currently surrounding the potential of biochar (charcoal created through the burning of biomass in low oxygen environments) in climate change mitigation and agriculture. This report attempts to summarise the arguments, assumptions and interests in the biochar debate and offer reflections on its prospects. The report begins by outlining what it calls the triple-win of biochar. The production of biochar can be tuned to release bioenergy or biofuels in the form of syngas and bio-oil, thus providing decarbonised biomass fuel. The burial of biochar can potentially enhance soils significantly, helping to retain nutrients and water whilst reducing the need for fertilisers. It is claimed that biochar resists degradation, thereby sequestering carbon within the soil for hundreds if not thousands of years.  In effect, we can potentially reverse the course of the last few hundred years by returning excess carbon to the ground. Mitigation effectiveness could vary considerably depending on a number of factors, including the type of biomass grown and indirect land use change impacts. For instance, clearing old growth forest to plant biochar feedstock could potentially have negative effects on carbon sequestration. The report concludes that waste-based systems hold the advantage on both technical and sustainability grounds and low-tech projects in developing countries have the greatest cost-effective potential. Risks and uncertainties are also discussed, for example the possibility of land-grabs for the production of biomass feedstock. The final section of the report concerns biochar's capacity to increase agricultural productivity through soil enhancement, which is a topic of considerable debate. The report underlines that while more research is needed, it is important to not allow mere potential to lock-in the favouring of scale and profit over local livelihoods.