Despite the proliferation of urban net-zero targets, the integration of CDR into city action plans poses significant challenges, particularly in terms of upholding the integrity of urban climate commitments.
My research focuses on the Climate Neutral and Smart Cities Mission, which involves 112 European cities aiming to reach net-zero by 2030. By assessing the action plans of 103 of these cities, we identified success stories as well as crucial gaps in urban planning for negative emissions, notably on the quantification of residual emissions, the identification of suitable emissions compensation options, and strategic planning. Our analysis reveals that while cities are prioritizing land-based temporary carbon sinks, such as urban revegetation and greening, the use of carbon credits and permanent CDR options is distrusted or underexplored.
To evaluate the robustness of urban CDR strategies, we developed the RESRI index (Residual Emissions Strategy Robustness Index), a lumped index that considers six critical dimensions: the ability to quantify residual emissions, the identification of compensation options, the quantification of sequestration potential, the timing of compensation, MRV provisions, and the overarching governance. The RESRI index provides a comprehensive framework for assessing the effectiveness of urban CDR strategies, and our results show that while some cities are making progress, many face significant challenges in developing robust plans.
Our research also highlights the need for cities to prioritize continued emissions reduction over compensation, diversify CDR portfolios, and engage in peer-to-peer mentorship and multilevel governance. To support cities in this effort, we have released the first-ever guidance on negative emissions for cities, accompanied by a summary for decision-makers.
I look forward to sharing these insights and resources with you and I hope we can explore together how science can support decision making in this fascinating - yet generally ill-understood - domain.