|Abstract: ||過去100年來，造成全球暖化的主因是溫室氣體過量的排放，其中CO2的影響最顯著。在減緩暖化的建議解決方案中，科學技術層面的減碳、碳捕捉與碳封存等有關碳的掌握與操控以及人文法律層面的排放限制成為不可或缺的考量與措施。 本研究蒐集各種學術領域有關全球暖化的研究報告，對碳源與碳沈積的看法進行整理分析，並分別將大氣與海洋的碳預算進行重估更新。同時以實驗分析四種經濟二枚貝的貝殼與其碳酸鈣組成，連同世界糧農組織與台灣漁業年報二枚貝的漁業統計資料，評估貝類養殖所具有的碳隔離能力對降低大氣CO2含量的潛力，並與森林的碳沈積能力、其他鈣化生物的鈣化能力以及碳捕捉與碳封存等建議的解決方案進行比較。 資料分析結果顯示，扣除海洋與陸地生態的吸收，目前的大氣每年增加46.7億噸碳的CO2。從實驗結果與漁業統計資料估得全世界二枚貝的養殖包括牡蠣、文蛤、孔雀蛤與蜆的碳隔離能力分別為225,200、182,000、78,800、以及2,436噸碳，加上其他海水二枚貝合計其碳隔離能力可達53萬噸碳，可減少大氣CO2增加量的0.0113%，此能力相當於1,100萬公頃的造林。在單位面積的碳隔離能力方面，本研究以台灣的養殖產量與面積估計牡蠣、文蛤、與蜆的碳隔離能力分別達0.126、0.256、與0.712噸碳/公頃/年、與森林的0.479噸碳/公頃/年相比較並不遜色，蜆的碳隔離能力甚至高於森林。然而異於森林受面積、生物量容量、及生態演進的限制，貝類的碳隔離成效卻可進行長期的持續累積。二枚貝的碳隔離能力雖不及珊瑚生態系的1.8噸碳/公頃/年，然而對於目前的全球暖化或海洋酸化，珊瑚易受傷害不易復育，而二枚貝的養殖產量卻未受影響，由此更突顯以二枚貝來進行碳隔離的優越性。另外貝類養殖本身已具經濟價值，不需為了碳隔離額外付出成本，又可賺取碳權，此種一舉數得的作法，在經濟考量上應具吸引力而值得去推廣。|
The main reason for the global warming over the past century is the excessive emission of greenhouse gases, among which CO2 plays the major role. Among the proposed solutions to lessen global warming, either by technical ways to reduce carbon footprints and implement carbon capture and storage (CCS) or by social and legal means to constrain CO2 emission becomes indispensable. This study gathered information about global warming from various sources, identified and reexamined major carbon source and carbon sink, and updated the estimation of carbon budget in the atmosphere and ocean. Furthermore, we analyzed shell and calcium carbonate composition of four economic bivalves, oyster, hard clam, blue mussel and freshwater clam. Together with fishery statistics from Food and Agriculture Organization of the United Nations and Taiwan Fisheries Yearbook, we evaluated the capacity of carbon sequestration capacity from bivalve aquaculture, compared that with carbon sink capacity from forests, calcification capacity of other calcifying organism and concluded its feasibility to reduce CO2 in atmosphere. Literature review and synopsis indicated yearly CO2 increment in atmosphere is 4.67 Gt C, after the deduction from absorption by ocean and terrestrial ecosystem. The estimation from experiment and fishery statistics showed that global carbon sequestration capacity from bivalve culture would be 225,200, 182,000, 78,800 and 2436 tC for oyster, clam, mussel, and freshwater clam, respectively. When other bivalves were included, total CO2 sequestrated would be 530,000 tC, or 0.0113% of the CO2 increment in the atmosphere. This amount is equivalent to 11 million hectares’ restoration of forest. From bivalve aquaculture statistics in Taiwan, we estimated the carbon sequestration capacity be 0.126, 0.256, and 0.712 tC ha-1yr-1 for oyster, clam, and freshwater clam, respectively, of which the last one is even higher than that for forest, 0.479 tC ha-1yr-1. While carbon sequestration and its accumulation in forest is limited by area, biomass containment and ecological succession, no such constraints applied on bivalve aquaculture. Although the carbon sequestration capacity of coral ecosystem (1.8 tC ha-1yr-1) is higher than that of bivalve aquaculture, coral is fragile to global warming and ocean acidification and hard to restore and recover its ecosystem. On the contrary, global bivalve aquaculture production for the past 50 years only showed increasing trend, unaffected by global climate change. This further demonstrates the biological superiority of bivalve aquaculture for carbon sequestration. Moreover, bivalve aquaculture per se is economically valid, no extra cost is necessary to pay for carbon sequestration, and along its production carbon credit is earned. Therefore, for the aforementioned multi-benefits, bivalve aquaculture should be attractive for the investors and promoted for carbon sequestration.