Oceanic Blue Carbon in Seas around Taiwan

Oceanic Blue Carbon in Seas around Taiwan

In order to mitigate the impacts of climate change, achieving carbon neutrality has become paramount. Previously, the estimation of negative carbon emissions was primarily focused on green carbon and yellow carbon. However, the oceans constitute one of the major global carbon pools, absorbing approximately 25-30˜ of the carbon dioxide from the atmosphere. Taiwan is committed to achieving net-zero carbon emissions by 2050, and the contribution of carbon absorption by the surrounding water cannot be overlooked. Therefore, this study aims to comprehensively review research on oceanic blue carbon (carbon sequestration or particulate organic carbon (POC) flux entering the bottom of the euphotic zone) sinks in Taiwan's territorial waters and exclusive economic zone. The results indicated that the carbon sequestration within Taiwan's territorial waters was 4.0±0.7 Mt-CO2 yr−1. Within the exclusive economic zone (EEZ), the carbon sequestration in the East China Sea, the northern South China Sea, and the western North Pacific Ocean were 49.3±14.9, 19.9±4.5, and 26.4±7.8 Mt-CO2 yr−1, respectively. In other words, carbon sequestration by deep-sea blue carbon can account for about 33.5˜ of annual carbon emissions in Taiwan, suggesting that deep-sea blue carbon cannot be ignored in order to achieve net-zero carbon emissions. Estimation uncertainty of oceanic blue carbon in seas around Taiwan can be affected by overlapping EEZs, lateral carbon transport, typhoons, mesoscale eddies, and internal waves, but detailed spatio-temporal investigations in seas around Taiwan are still needed.