Do we have enough information to scale up carbon removals sustainably?
As COP29 of the UN Framework Convention on Climate Change (UNFCC) commences in Azerbaijan, the need for effective and sustainable strategies to reduce greenhouse gas emissions is more critical than ever. However, most global scenarios also rely heavily on carbon dioxide removals (CDRs) to keep within the Paris Agreement temperature targets, and many ‘net-zero’ pathways indicated by governments contain a significant amount of CDR.
But do we know what the wider effects of these CDR practices will be, or which approaches might be more or less sustainable?
A new paper, led by Dr Isabela Butnar of UCL and NbSI’s Dr John Lynch, argues that we currently have only limited evidence to address these important questions.
Life Cycle Assessment (LCA) methods, widely used to assess the environmental impacts of products and services, are increasingly used to inform policy decision-making around CDR practices, to suggest which practices are most favourable and whether there may be adverse effects that need to be considered. However, this new analysis highlights the urgent need for more comprehensive and consistent LCA studies to enable comparison between different CDRs and reveal the potential consequences of scaling CDRs up in the future.
Reviewing the Life Cycle Assessment (LCA) literature on CDR, the authors found that while there is much valuable and informative research, which usually covers the full life cycle of removals, studies of different types of carbon removal have different methods and norms, making cross-comparison challenging or impossible. In many cases, research only explored a small number of impacts beyond climate effects, if any, so there is limited data on the wider effects – positive or negative – of many CDR practices. The social and environmental impacts of CDR must be understood in order to scale-up practices that support co-benefits, and do not risk damage to the biosphere or human rights violations. Further analysis on the wider effects of CDR can help to identify practices which prioritise multiple core benefits alongside carbon sequestration, such as biodiversity and ecosystem services.
Finally, LCA papers predominantly take an ‘attributional’ rather than ‘consequential’ approach, meaning that they track impacts at project-scale, but cannot reveal systemic effects: key to understanding whether large-scale roll-out can be sustainable.
The paper concludes that more consistent and comprehensive LCA studies will be vital in determining the roles of different carbon dioxide removal practices in a sustainable future. This evidence would enable us to plan the best way to deploy CDR to achieve our climate commitments while minimising trade-offs and maximising additional benefits.
The work was undertaken as part of the CO2RE greenhouse gas removal hub, in collaboration with the wider GGR-D Biochar, Enhanced Rock Weathering, Peatlands, Perennial Biomass Crops and Woodland Creation & Management, demonstrators.
Read the paper: “A Review of Life Cycle Assessment Methods to Inform the Scale-Up of Carbon Dioxide Removal Interventions”
Read about the need for social and ecological sustainability limits for CDR here.
