The Intergovernmental Panel on Climate Change (IPCC) has been tasked by United Nations policymakers to assess hypothetical pathways to limit global temperature rise to levels consistent with the goals established by the 2015 UN Paris treaty. Among the identified pathways in the 2018 IPCC report for keeping warming below either 2.0°C or 1.5°C, almost all require the deployment of still speculative carbon removal and storage methods, also referred to as “negative emissions technologies.”
Yet most carbon removal methods, such as bioenergy and carbon capture with storage or direct air capture, remain at the preliminary research and assessment stage, with a great deal of uncertainty over their technical feasibility, social acceptability, cost, and associated impacts. In addition, some argue that the reliance on unproven carbon removal methods to fulfill climate policy goals creates a false sense of complacency about the need for an immediate and aggressive transition away from fossil fuels. As experts raise considerable doubts about the feasibility of carbon removal technologies, they have also called for a more honest public debate about the contestable assumptions involved in IPCC assessments and the relatively invisible function of scenario modelling and carbon removal methods in current policy debate.
This report looks at why the entire field of carbon removal needs additional scrutiny and how to build a better carbon removal conversation. To inform this conversation, this report:
- Details the role of the IPCC in providing input to policymakers and the arguments in favor of pursuing carbon removal methods.
- Explains three of the most prominent carbon removal methods discussed in policy circles today, why bioenergy with carbon capture and storage (BECCS) in particular plays an outsized role in IPCC reports, and the arguments by critics warning of their uncertain nature.
- Describes the process by which key uncertainties about the feasibility of achieving ambitious global temperature targets were ignored by policymakers at the UN Paris meetings.
- Describes the central function that constructive disagreement and public dialogue must play in making responsible decisions about carbon removal methods.