Bioenergy for climate change mitigation: Scale and sustainability

Open access article in the Journal GCB Bioenergy. Available at: https://onlinelibrary.wiley.com/doi/10.1111/gcbb.12863

Many global climate change mitigation pathways presented in IPCC assessment reports rely heavily on the deployment of bioenergy. Bioenergy plays a key role in decarbonization in modelled future pathways, supporting energy system transformation, especially in hard-to-abate applications such as industry, aviation and shipping, and, when linked with carbon capture and storage (BECCS), can remove CO2 from the atmosphere, next to providing renewable energy. This article reviews the literature on bioenergy use for climate change mitigation, including studies that use top-down integrated assessment models or bottom-up modelling, and studies that do not rely on modelling. The article summarizes the state of knowledge concerning potential co-benefits and adverse side effects of bioenergy systems and discusses limitations of modelling studies used to analyse consequences of bioenergy expansion.

The implications of bioenergy supply on climate change mitigation and other sustainability criteria are context dependent and influenced by feedstock, management regime, climatic region, scale of deployment and how bioenergy alters energy systems and land use. Depending on previous land use, widespread deployment of monoculture plantations may contribute to climate change mitigation but can cause negative impacts across a range of other sustainability criteria. Strategic integration of new biomass supply systems into existing agriculture and forest landscapes may result in less mitigation but can contribute positively to other sustainability objectives. For example, integration of suitable perennial biomass production systems in regions dominated by annual crop cultivation has been shown to have positive benefits across a range of sustainability criteria, including soil health, biodiversity and water quality.

There is considerable variation in evaluations of how sustainability challenges evolve as the scale of bioenergy deployment increases, due to limitations of existing models, and uncertainty over the future context with respect to the many variables that influence alternative uses of biomass and land. Integrative policies, coordinated institutions and improved governance mechanisms to enhance co-benefits and minimize adverse side effects can reduce the risks of large-scale deployment of bioenergy.

Bioenergy and the use of land to produce biomass, is an important part of many climate mitigation strategies but there are limits to its use due to trade-offs with sustainability. At the same time, there are opportunities for win-win response options that can enhance mitigation, increase resilience and co-deliver across a range of sustainability criteria. Nevertheless, it is not possible to maintain current systems and trends in consumption patterns by simply replacing fossil carbon with biogenic carbon. Conservation and efficiency measures for energy, land and biomass can support greater flexibility in achieving climate change mitigation and adaptation.

Key take-aways:

• Bioenergy and BECCS play a key role in long term decarbonisation scenarios.
• There are limits to the use of biomass due to trade-offs with sustainability – limitations are context dependent.
• It is not possible to maintain current systems and trends in consumption patterns by simply replacing fossil carbon with biogenic carbon.
• Integrative policies, improved governance mechanisms can enhance co-benefits, minimize adverse side effects and trigger win-win responses (also supporting other sustainability objectives) in the further deployment of bioenergy.

Full citation: Calvin, K., Cowie, A., Berndes, G., Arneth, A., Cherubini, F., Portugal- Pereira, J., Grassi, G., House, J., Johnson, F. X., Popp, A., Rounsevell, M., Slade, R., & Smith, P. (2021). Bioenergy for climate change mitigation: Scale and sustainability. GCB Bioenergy, 13, 1346– 1371. https://doi.org/10.1111/gcbb.12863