Seagrass offers the largest scope for restoration among blue carbon habitats, due to their greater potential extent along with efficient space occupation through their clonal growth. Here we model the upper limit to the value of carbon removal if seagrass were to be restored to approach their maximum global extent, estimated at about one million km 2 to yield up to 17.8 CO 2-eq . This corresponds to a total value of the associated carbon credits of USD 1.13–2.27 trillion, depending on the length of exponential clonal growth. More conservative scenarios, considering lower, updated, carbon sequestration rates, bring down the upper limit to the long-term carbon sequestered by rebuilding seagrass meadows to 20% down to 3.29 Pg CO 2-eq , valued at USD 0.28–0.57 trillion. When this lower carbon sequestration estimate is referred to seagrass recovery to a 1970 baseline, rather than the maximum possible extent, the corresponding carbon removal is further reduced to 1.64 Pg CO 2-eq , valued at USD 0.13–0.27 trillion. These results show that the value of the climate change mitigation potential of seagrass restoration will be sizeable even if only partial recovery and/or a lower average areal carbon removal could be achieved.
Chami et al. (Sun,) studied this question.