Three challenges to marine carbon dioxide removal

Reaching the Paris Agreement target to limit global warming below 1.5 °C requires both decarbonization and the removal of carbon dioxide from the atmosphere. Here, we highlight three challenges to marine carbon dioxide removal (mCDR) (knowledge gaps, ecological and social risks, and inadequate governance), which must be addressed before considering mCDR as a scalable climate solution. Until then, field experiments should remain strictly regulated and limited to advancing scientific understanding.