Study shows: No efficiency loss when combining land and ocean CDR

A new paper by Yiannis Moustakis, Tobias Nützel, and Julia Pongratz has been published in Nature Communications. Titled "No compromise in efficiency from the co-application of a marine and a terrestrial CDR method", the research presents the first Earth System Model-based analysis of large-scale combined deployment of land- and ocean-based carbon dioxide removal (CDR) methods.

Key Findings: Combined CDR Keeps Its Efficiency

Achieving the Paris Agreement’s climate targets will require the large-scale implementation of CDR methods, both on land and in the ocean. Until now, it remained uncertain how Earth system feedbacks would respond to such combinations at scale. This new study addresses that knowledge gap by running simulations with two Earth System Models, analyzing various CDR deployment scenarios through the 21st century.

The research team conducted 42 simulations under a high-emissions trajectory, evaluating Afforestation/Reforestation (AR) and Ocean Alkalinity Enhancement (OAE) separately and in tandem. Results show that global carbon fluxes increase linearly as CDR is scaled up, even when methods are combined—indicating that joint application of land- and ocean-based approaches does not reduce carbon removal efficiency.

Lead author Yiannis Moustakis highlights: “Our results are very encouraging. “They suggest that we can design more diverse CDR portfolios including both marine and terrestrial methods without losing effectiveness, despite the emerging Earth system feedbacks. This could help reduce pressure on land systems, which can have severe socioeconomic consequences. To support this process, we urgently need more research also into marine CDR to understand its mitigation potential and environmental impacts. And we must be clear: CDR is no substitute for steep emissions reductions – it's a necessary complement.”

Why the Results Matter for Climate Strategy

The findings have significant implications for future climate policy and CDR strategy design:

• They suggest Increased flexibility in selecting and combining CDR options.
• They suggest that there is no trade-off between combining methods and maintaining effectiveness.
• They allow for more sustainable land use pathways by integrating ocean-based CDR methods

The authors emphasize the importance of continued research, especially on marine-based CDR, to better understand its functioning and ecological consequences.

Authors: Yiannis Moustakis, Hao-Wei Wey, Tobias Nützel, Andreas Oschlies, Julia Pongratz

Published in: Nature Communications

Read the article: https://www.nature.com/articles/s41467-025-59982-x