Global efforts to reduce emissions remain inadequate which resulted in an increasing need for negative emission technologies that actively remove and permanently sequester CO₂ from the atmosphere.

We highlight the rapid growth of commercial mCDR start-ups, despite limited research and potential irreversible harm to marine ecosystems. These activities appear uncoordinated, lack oversight, and show no evidence of compliance with international frameworks such as the London Protocol. Our study underscores the urgent need for its ratification.