Oyster farming helps reducing China's greenhouse gas emissions for food production

Bivalve farming represents an economically and ecologically beneficial approach to addressing the escalating global food demand. Notably, oysters, which constitute a substantial proportion of cultivated bivalves, exceeding 40 %, demonstrate considerable potential for expansion. Assessing the lifecycle greenhouse gas (GHG) emissions of oyster aquaculture is critical for establishing emission benchmarks and advancing sustainable food systems, yet remains understudied. This study quantifies cradle-to-gate GHG emissions for Pacific oyster ( Crassostrea gigas ) farming in China, spanning algae culture, hatchery rearing, and sea farming. Results reveal remarkably low emissions of 92.97 kg CO 2 -eq per metric ton of fresh oyster. Sea farming (38.75 %) and hatchery operations (37.99 %) dominate emissions, while algae cultivation contributes minimally (1.43 %). Oyster protein production generates just 3.30 % of beef's GHG emissions per kilogram. In 2022, China's oyster farming provided over 0.15 million metric tons of protein, offsetting an estimated 15.33 million metric tons of CO 2 -eq compared to beef. Incorporating renewable energy, optimizing aquaculture practices, improving larval survival rates, and using sustainable materials could reduce emissions by 10–30 %. These findings underscore oyster aquaculture as a low-emission protein source with significant scalability, offering a viable pathway to mitigate food-sector climate impacts while meeting rising global protein demand. • This research endeavor concentrates on the lifecycle greenhouse gas emissions of cultivated Pacific oysters in China, whose oyster production accounted for over 87 % of the global. • In terms of GHG emissions per kilogram of protein produced, oysters contribute a mere approximately 3.30 % of the emissions associated with beef production. • The findings indicate that a total of 17.77 gigatons of CO 2 -eq could be mitigated in the meat production sector between 2020 and 2060.