Climate engineering could change ocean chemistry and marine life

A new study reviewed eight climate intervention methods and found each could alter ocean chemistry and ecosystems; electrochemical ocean alkalinity enhancement showed the lowest direct risk among the approaches reviewed, but no method is free of uncertainty and more research is needed before large-scale ocean deployment.

Climate change is already raising sea levels, warming the ocean and altering marine ecosystems. Researchers reviewed how proposed climate interventions could affect the ocean and marine life. The review grouped interventions into carbon dioxide removal (CDR) methods and solar radiation modification (SRM), which operate in different ways. The authors found that some strategies may carry lower direct risks than others, but all involve uncertainties. Key findings: - Interventions fall into two broad types: CDR approaches that remove or store carbon and SRM approaches that temporarily reduce incoming sunlight; each category affects the ocean differently. - Electrochemical ocean alkalinity enhancement was identified as having the lowest direct risk to marine biology among methods reviewed, though it requires safe handling or neutralization of acidic byproducts. - Biological CDR methods (for example, boosting algal growth or sinking biomass) can change nutrient distributions, risk local oxygen depletion, and alter food-web dynamics, with possible downstream effects on fisheries. - Models used to assess interventions lack data on some biological processes and contaminants; the authors say laboratory studies and small-scale field experiments are needed to improve understanding. Summary: The review indicates that climate interventions could reshape ocean chemistry and the composition of marine communities, with implications that could reach fisheries and other ecosystem services. While electrochemical alkalinity enhancement and adding carbonate minerals were seen as relatively lower-risk options, uncertainties remain about contaminants, nutrient effects and long-term outcomes. The article notes that some commercialization is underway and that further laboratory work, improved models and careful small-scale testing are needed; decisions about large-scale deployment are undetermined at this time.