Michael Obersteiner looks back on the history of bioenergy with carbon capture and storage (BECCS).

Twenty years ago, large-scale engineered negative emission technologies were first considered in creating pathways towards more ambitious climate mitigation targets. This came about by the realization that combining bioenergy with CCS is effectively a negative emissions technology. It was Kenneth Möllersten who laid the foundation for this discovery as he was researching the climate mitigation benefits of combining pulp and paper making with CCS.

I remember Kenneth calling me after we met for the first time at a climate conference in Cambridge asking if he could get double carbon credits for running a pulp mill with CCS. I thought about it and realized that this is a negative emission technology (NET) that would make large scale carbon sequestration way more effective and efficient than large-scale afforestation only – something we studied at IIASA at that time. Immediately we started to generalize the technology and eventually called it BECCS. BECCS would also overcome the thorny problem of permanence of forest carbon sequestration.

A game changer

Kenneth and I decided to immediately write a letter to Science magazine as we were convinced that this was a major game changer for climate mitigation and eventually the setting of ambitious climate targets. We talked to our friends in the energy modelling community Keywan Riahi, Christian Azar and Kristian Lindgren who also immediately saw this new potential and together we created the first scenarios where the global energy system would become carbon negative before 2100.

We provided this information in an IIASA interim report, which never received much attention, but laid a foundation for the forthcoming Science letter. However, in retrospect, these early scenarios were the cradle of the types of scenarios we now see underpinning the Paris Climate Agreement. With these scenarios at hand, we had more confidence and submitted our letter to Science, which was published on October 26th, 2001, only some three weeks after my phone call with Kenneth. We invited several colleagues to join the paper who we knew were also supportive of the idea or, in the case of Peter Read, had floated the idea of negative emissions from BECCS even earlier.

BECCS as a climate risk management option

At that time, there was still a consensus that 450 ppmV appeared as an achievable climate target the world should aim for. There was an emerging pressure from climate scientists that a two-degree target would be a safe target, which through aggressive decarbonization would have been still realistic to achieve at that time. We therefore opted to motivate the preparation of large-scale deployment of negative emissions, through BECCS, as a climate risk management option.

The most prevailing tipping point story back then was abrupt climate change with Thermohaline circulation shutdown as the prime example. Thus, we recommended large-scale afforestation as a preparatory measure. In a mode of anticipative climate mitigation, we envisaged that science would have progressed enough 20-30 years down the line and be able to determine thresholds for abrupt climate change. In that case, by 2020-30, the world would be able to avoid a crossing of such thresholds by starting to remove CO2 from the atmosphere using BECCS and other NETs, which we called the basket of negative emission technologies. Furthermore, direct air capture and biochar had started to emerge as potential NETs. Today, the scientific discussion commonly refers to NETs as Carbon Dioxide Removal (CDR).

There were several issues we listed back then that would justify the development of NETs such as BECCS. They ranged from technological surprises, institutional inertia, failure to cooperate on the international level, and intergenerational equity if irreversible climate damage could be avoided.

Since then, a lot has happened.

Not much progress

However, most of the issues we discussed back then have not progressed much. It is rather sobering that today BECCS is considered by many (mostly armchair experts) as a fundamentally unsustainable technology. BECCS is currently associated with large contributions from fast-growing plantations, deteriorating biodiversity, and the jeopardisation of food security.

Although the potential of such trade-offs is real, there are also technical implementation scenarios of large-scale BECCS or bioenergy-based NETs that would create co-benefits rather than trade-offs. Bioenergy-based NETs, including BECCS, appear especially useful for successive restoration measures as well as proactive forest climate adaptation. These are all issues that will need to be discussed and researched more thoroughly in the future and tested in the field.

Time to produce evidence and facts on BECCS deployment

It would be a grave mistake to discard BECCS and other biomass-based NETs from the permissible set of climate mitigation actions. To the contrary, given the opportunities to test and measure the actual impacts of real deployment, society should be guided by actual evidence on all sustainability dimensions rather than poorly informed assumptions. There is still a long journey ahead of us to make BECCS and other NETs truly sustainable and large enough that we can avoid climate break-down. Now in 2021 it is time to experiment with real deployments and learn from the experiences and measured evidence. It is time to confront the debate with facts rather than debating over assumptions.