Duncan Brack, Richard King
Decisions about when, where and how to achieve widespread carbon dioxide removal (CDR) are urgently required. Delays in developing the requisite policy and regulatory frameworks increase the risks of overshooting climate goals and will necessitate much larger negative emissions initiatives in the future. Yet the deployment of bioenergy with carbon capture and storage (BECCS) at the scales assumed under most Paris‐Agreement‐compliant emission‐reduction pathways is unlikely. More generally, the sustainability of large‐scale BECCS is questionable given its extensive land, water, and energy requirements for feedstocks and the competing necessity of these resources for the provision of ecosystem services and attainment of multiple Sustainable Development Goals. BECCS on a more limited scale, however, could have more benign impacts if feedstocks were restricted to wastes and residues. There is also widespread recognition that extensive afforestation, reforestation and forest restoration have critical roles in reducing greenhouse gas emissions to net zero. To date there has been little focus on the optimum strategies for integrating land‐based CDR approaches – under which circumstances forest areas are best left undisturbed, managed for conservation, and/or managed for harvested wood products, and how these options affect the availability of residual feedstocks for BECCS. This paper reviews this debate and suggests appropriate policy measures.
Three principal policy implications emerge:
First, the necessity of abandoning the assumption, common in integrated assessment models, that BECCS is the pre‐eminent carbon removal solution. Rather it needs to be analysed alongside all other negative emissions technologies (NETs), on the basis of full lifecycle carbon balances (including dropping the assumption that biomass feedstock is inherently carbon‐neutral), as well as other ecosystem and sustainability co‐benefits and trade‐offs.
Second, urgent action is required to scale up the development and deployment of sustainable NETs. No single NET – whether BECCS, nature‐based, or otherwise – will achieve the scale of CDR required in the vast majority of 1.5°C and 2°C mitigation scenarios, let alone do so sustainably. But portfolios of multiple NETs, deployed sensitively at modest scales, will be invaluable for achieving climate security. This requires designing policy and financial mechanisms that are sufficiently attuned to the contextual specificities of each potential deployment, but which are sufficiently catalytic to galvanise appropriate and complementary actions at adequate scales and with enough urgency.
Third, we need to be absolutely clear that all CDR efforts have to be additional to – not substituting for, or detracting from – urgent acceleration of conventional abatement actions. This means we need to accelerate conventional abatement action as rapidly as possible. There are too many drawbacks and uncertainties associated with BECCS and other NETs to place excessive reliance on them – though carbon removal solutions will undoubtedly be needed.