As the brunt of climate change begins to be felt globally, efforts are made to reduce greenhouse gas (GHG) emissions to mitigate climate change. One of the proposed approaches is replacing fossil fuels with renewable and climate-friendly energy sources such as bioenergy (energy from plant biomass). For years, fossil fuels have been the major source of energy for homes, transportation and in most industrial applications. However, owing to the enamours amount of carbon (C) emissions associated with this energy option, environmentalists and like-minded groups continue to advocate for the consideration of sustainable energy options such as bioenergy. Although, just like fossil fuels, the production and consumption of energy from biomass emits carbon dioxide (CO2) into the atmosphere. It is, however, understood that the CO2 released through the combustion of bioenergy comes from the C stored by those plants during their lifetime. Hence, bioenergy is a C neutral energy source. Whereas this appears to be a laudable and climate-friendly energy solution option, the sources of biomass for bioenergy, otherwise known as ‘bioenergy feedstock,’ is what has generated recent controversies.
In major biofuel production countries, crops such as corn (Zea mays), sugarcane (Saccharum officinarum), soybeans (Glycine max), oil palm (Elaeis guineensis), canola (Brassica napus) and other oilseeds and cereals have largely been used for bioenergy. In addition to being food crops, these cops are grown on prime agricultural lands, thereby competing with food crops both for land occupation and for end-use. Considering continual issues surrounding food insecurity, which continues to threaten the global population, the question remains if there is and will be sufficient food crops for human and livestock consumption as well as for energy use. Already, there exist enormous pressure to increase food production to meet demand for a growing population. Therefore, diverting food crops and other productive resources from food production towards the production of bioenergy will threaten access and availability of adequate food supplies. One proposed strategy for overcoming this bottleneck is by increasing crop yield through the expansion of agricultural lands and/or the application of mineral fertilizers. However, the emissions of GHGs such as nitrous oxide (N2O) and CO2 associated with the clearance of new vegetation and fertilizer use to increase crop production and yield cannot be discounted. Therefore, what was initially regarded as a solution to a sustainability challenge (energy security and climate change mitigation) now appears to be a sustainability problem itself.
Moreover, there are other arguments which favour the use of on-farm crop residue for bioenergy. It is claimed that doing so will ensure that food crops are not diverted into energy production. On the contrary, crop residues when retained on the farm are an important source of nutrients for subsequent crops. Removing these residues for energy purposes might increase the demand for mineral fertilizers. The result of this practice is not only unsustainable, but it also produces GHG emissions in addition to generating other environmental consequences. So, the question remains: should we feed it and ignore the consequences of climate change or fuel it and ignore the consequences of food security? Alternatively, how do we strike a balance between bioenergy and food security?
A proposed solution to this dilemma seems to lie in a ‘problem worth having’ and that is marginal lands. The conversion of marginal lands to produce non-food crops capable of energy production is an innovative approach of managing these lands to achieve a win-win-win solution of energy security, climate change mitigation, and regenerating these lands without compromising food security. Among some of these non-food crops capable of growing on marginal lands are perennial grasses and woody crops such as switchgrass (Panicum virgatum), miscanthus (Miscanthus giganteus), willow (Salix miyabeana), poplar (Populus spp.), etc. In addition to having higher energy capabilities, these crops rapidly accumulate biomass on marginal lands with little or no external fertilizer requirements. Additionally, their long-term land occupation makes them good candidates for regenerating these marginal lands on which they grow, providing other essential ecosystem services as well.
Presently, a long-term study is ongoing at the Guelph Agroforestry Research Station to evaluate different perennial bioenergy crops established on a marginal. Studies have previously been conducted in these perennial stands of willow, switchgrass, and miscanthus and found out that these crops have high energy and yield potentials on marginally productive agricultural lands. These crops have therefore, been recommended for establishment on marginal lands in southern Ontario for energy use without compromising food security. However, since their long-term GHG implications are not well understood yet, my current PhD study is exploring the GHG emissions associated with these crops and their long-term soil C sequestration potentials. Information on this study will help us to understand the impact establishing perennial bioenergy crops on marginal lands, could have on the climate aside from playing a key role in ensuring food security.
For further reading:
Lutes, K., M. Oelbermann, N. V. Thevathasan, and A. M. Gordon. 2016. Effect of nitrogen fertilizer on greenhouse gas emissions in two willow clones (Salix miyabeana and S.dasyclados) in Southern Ontario, Canada. Agrofor Syst DOI: 10.1007/s10457-016-9897z
Mann, J. D. 2012. Comparison of yield, calorific value and ash content in woody and herbaceous biomass used for bioenergy production in Southern Ontario, Canada. M.Sc. Thesis, University of Guelph, Canada.
Norgrove, L. 2010. Impacts of biofuel production on food security. IUFoST Scientific Information Bulletin SIB.https://www.researchgate.net/publication/232071898_impacts_of_biofuel_production_on_food_security (Accessed Dec. 09, 2019)
Searchinger, T. and R. Heimlich. 2015. Avoiding Bioenergy Competition for Food Crops and Land. Working Paper, Installment 9 of Creating a Sustainable Food Future. Washington, DC: World Resources Institute. Available online at https://wriorg.s3.amazonaws.com/s3fspublic/avoiding_bioenergy_competition_food_crops_land.pdf (Accessed December 09, 2019).
Wise, T. A. 2012. The cost to developing countries of U.S. corn ethanol expansion. Global Development and Environment Institute Working Paper No. 12-02. http://www.ourenergypolicy.org/wpcontent/uploads/2012/10/1202WiseGlobalBiofuels.pdf (Accessed Dec. 09, 2019