Out of the blue carbon box: toward investable blue natural capital.

In 2019, we found that the concept of blue carbon had begun to solidify in the preceding decade around activities that could achieve mitigation through conservation and restoration and on ecosystems with high levels of data. Five years later, the available data have increased, and so too have the ecosystems that are included in national carbon markets and carbon market methodologies (e.g. seaweed and supratidal forests). While the implementation of blue carbon strategies continues to advance in both the carbon and emerging biodiversity markets, the scale of investment is inadequate for the action needed to meet global targets of the Paris Agreement and Kunming-Global Biodiversity Framework. The developing finance mechanisms for investment in blue natural capital offer additional potential for action on conservation and restoration of blue carbon ecosystems at large scales, although governance systems are challenged to deliver just and equitable outcomes. Blue carbon research and implementation is characterized by deep collaboration among diverse disciplines and actors, which continues to be crucial to achieving conservation and restoration goals.