Artificial algal blooms could remove atmospheric carbon — but can they be used responsibly?

NEWS AND VIEWS

29 July 2026 Artificial algal blooms could remove atmospheric carbon — but can they be used responsibly? Adding iron to the ocean to stimulate carbon-absorbing phytoplankton could have ecological consequences that reach far beyond the intervention site. By Sara Nawaz ORCID: http://orcid.org/0000-0003-4337-1453 0 Sara Nawaz Sara Nawaz is at the Institute for Responsible Carbon Removal, American University, Washington DC 20016, USA, and the Institute for Resources, Environment and Sustainability, University of British Columbia, Vancouver V6T 1Z4, Canada. View author publications PubMed Google Scholar

It is unlikely that global warming levels can be kept below the 1.5 °C or even 2 °C limits set out in the Paris climate agreement without the large-scale removal of atmospheric carbon dioxide1. One way to achieve this might be ocean iron fertilization (OIF), which draws carbon out of the atmosphere by stimulating the photosynthesis of marine algae called phytoplankton. The potential use of this strategy is, however, deeply contested. Writing in Nature, Yu et al.2 report simulations of OIF that show that its effectiveness and ecological impacts would vary between regions, and that implementing it has the potential for far-reaching, unintended consequences.

doi: https://doi.org/10.1038/d41586-026-02126-y

References Intergovernmental Panel on Climate Change. AR6 Synthesis Report: Climate Change 2023 (IPCC, 2023). Yu, J. et al. Nature https://doi.org/10.1038/s41586-026-10795-y (2026). Silverman-Roati, K. & Webb, R. M. A Primer on International Agreements Relevant to Marine Carbon Dioxide Removal (Sabin Center for Climate Change Law, 2026). Arcusa, S. H. & Lackner, K. S. Environ. Sci. Policy 173, 104223 (2025). Buesseler, K. O. et al. Dialogues Clim. Chang. https://doi.org/10.1177/29768659261420631 (2026). Download references

Competing Interests The author declares no competing interests.

Subjects