Current climate efforts are not progressing quickly enough to prevent the world from overshooting the global emissions targets set in the Paris Agreement; accordingly, attention is turning increasingly to options for removing carbon dioxide from the atmosphere – ‘carbon dioxide removal’ (CDR).
Alongside afforestation and reforestation, the main option under discussion is bioenergy with carbon capture and storage (BECCS): processes through which the carbon emissions from burning biomass for energy are captured before release into the atmosphere and stored in underground reservoirs.
This pre-eminent status is not, however, based on a comprehensive analysis of the feasibility and impacts of BECCS. In reality, BECCS has many drawbacks.
Models generally assume that biomass for energy is inherently carbon-neutral (and thus that BECCS, by capturing and storing the emissions from combustion, is carbon-negative), but in reality this is not a valid assumption.
On top of this, the deployment of BECCS at the scales assumed in most models would consume land on a scale comparable to half that currently taken up by global cropland, entailing massive land-use change, potentially endangering food security and biodiversity. There is also significant doubt about the likely energy output of BECCS solutions.
BECCS may still have some role to play in strategies for CDR, depending mainly on the feedstock used; but it should be evaluated on the same basis as other CDR options, such as nature-based solutions or direct air carbon capture and storage (DACCS). Analysis should take full account of carbon balances over time, the requirements of each CDR option in terms of demand for land, water and other inputs, and the consequences of that demand.
There is an urgent need for policymakers to engage with these debates. The danger at the moment is that policymakers are ‘sleepwalking towards BECCS’ simply because most models incorporate it – or, almost as bad, it may be that they are simply ignoring the need for any meaningful action on CDR as a whole.