Engineered carbon removal has the potential to contribute significantly to addressing the climate crisis, but it is unlikely to be a stand-alone solution. The climate crisis is a complex issue that necessitates a multifaceted approach that includes both mitigation and adaptation strategies.
A new IIASA-led study investigated the fairness and feasibility of deep mitigation pathways with novel carbon dioxide removal, while taking institutional capacity to implement mitigation measures into account.
Meeting the Paris Agreement’s 1.5°C target will necessitate bold climate action this decade. Difficult questions remain about how to limit warming while respecting nations’ common but differentiated responsibilities and respective capabilities on the path to a sustainable future. To meet this challenge, significant emissions reductions are required to achieve net-zero emissions globally.
Among the new options being investigated in the scientific literature, engineered Carbon Dioxide Removal (CDR) such as Direct Air Capture of CO2 with Carbon Capture and Storage (DACCS) is a potentially promising technology that could help bridge this gap. DACCS captures carbon by passing ambient air through chemical solvents, and can be considered a form of CDR if the captured carbon is permanently stored underground. However, whether these novel technologies can help make lofty goals more attainable, or whether they can help achieve them more equitably, remains to be seen.
Our results show that new technologies for removing carbon from the atmosphere can play a role in ambitious climate policy, but they won’t be a silver bullet for solving the climate crisis.
Matthew Gidden
An interdisciplinary research group led by IIASA scientists developed new scenarios exploring fairness and feasibility in deep mitigation pathways, including novel CDR technologies, in their study published in Environmental Research Letters. For the first time, the team used DACCS in a well-known integrated assessment model called MESSAGEix-GLOBIOM to investigate how this technology might impact global mitigation pathways under various scenarios of environmental policy effectiveness based on country-level governance indicators.
“In current policy debates, concerns about the political feasibility and fairness of the current generation of climate mitigation scenarios are raised, and DACCS is often proposed as a possible solution. In our study we quantified under what conditions and how DACCS might address those concerns,” explains Elina Brutschin, a study co-author and researcher in the Transformative Institutional and Social Solutions Research Group of the IIASA Energy, Climate, and Environment Program.
When considering novel forms of CDR, the researchers emphasize that the goal of limiting warming to 1.5°C remains unchanged. The research team investigated how novel CDR interacts under different assumptions of techno-economic progress and the evolution of the regional institutional capacity to gain a broader perspective on pathways to limit warming. The researchers emphasize the risks of relying on unproven carbon removal technologies while also discussing the future role of novel CDR and similar technologies for developing countries.
When such risks are taken into account, the results show that novel CDR can keep pre-Paris climate targets within reach, but that increasing institutional capacity beyond historical trends is required to limit warming to the Paris Agreement’s 1.5°C goal, even with novel CDR processes. If new forms of CDR do not emerge in the near future, the study suggests that significantly improving institutional capacity to implement environmental policies, regulations, and legislation is critical to keeping warming below 2°C.
The authors go on to say that even after accounting for the potential future evolution of novel CDR technologies as well as inherent risks, the ‘fairness’ of overall outcomes did not improve significantly. DACCS had no effect on near-term global mitigation ambition, and additional carbon removal in developed economies accounted for only a minor portion of the mitigation required to meet stringent climate targets. This is because carbon dioxide removal in these areas does not compensate adequately for their historical emissions by mid-century.
The inability of DACCS to improve the fairness of outcomes, such as cumulative carbon emissions, in 1.5°C scenarios emphasises the idea that meeting global climate targets is a global effort that necessitates a ‘all-of-the-above’ mitigation strategy. When it comes to achieving climate goals, there is no room for manoeuvring.
However, the results show that engineered removals can help to make the post-peak temperature stabilisation (or decline) phase more equitable. This means that the full timeframe for accounting is critical for pursuing fair outcomes that are acceptable to the vast majority of Parties to the United Nations Framework Convention on Climate Change (UNFCCC).
“Our results show that new technologies for removing carbon from the atmosphere can play a role in ambitious climate policy, but they won’t be a silver bullet for solving the climate crisis. Developed countries especially need to cut emissions by more than half this decade, primarily by reducing existing sources of emissions while scaling up CDR technologies to be in line with the Paris Agreement,” says study lead author Matthew Gidden, a researcher in the IIASA Energy, Climate, and Environment Program.
The researchers emphasise the importance of the modelling community assessing the role of novel CDR in a structured manner in order to better understand robust outcomes and insights versus observations related to a given model framework or approach. In the future, these issues can be explicitly addressed in scenario design to achieve more equitable outcomes while taking into account the political realities of governments’ and institutions’ ability to enact strong climate policy.
