臺灣西部海岸濕地碳儲存效益

全球二氧化碳（CO2）濃度上升造成之極端氣候已嚴重威脅全球物種的生存。濕地碳儲存功能有助於調適氣候變遷，因此一旦濕地因不當開發而遭受破壞，將為社會帶來龐大成本。本研究透過文獻蒐集與實地調查六個濕地（涵蓋紅樹林、潟湖、潮間帶、鹽田、草澤、魚塭、農地等七種植被類型）內土壤與植物的單位面積碳儲存量，並且應用效益函數移轉估算臺灣西部22處海岸濕地共26,420公頃的碳儲存總量與碳儲存效益。實地調查結果發現：相對其他植被類型，紅樹林濕地之單位土壤碳儲存量較高，其中四草濕地海茄冬區最高約13,318公噸，淡水河挖子尾濕地水筆仔區最低約1,980公噸；而潮間帶僅408公噸。臺灣西部22處濕地的CO2儲存量共約7,758萬公噸，而碳儲存效益以國內碳稅稅率（每公噸CO23,000元）估算約2,327億元；以國際減碳成本估算約157億元；以碳社會成本估算約252～1,352億元。本研究結果提供決策者與社會大眾在權衡濕地保育或開發利用時，瞭解濕地的碳儲存效益相當大，僅有回歸至濕地保育法提倡的明智利用，才能兼顧濕地生態永續與保有生態系統服務提供的經濟效益。 The literature points out climate change has seriously threatened the survival of global species, meanwhile the carbon storage in wetlands plays an important role in climate change adaptation. This paper aims to estimate the amount and benefits of carbon storage for 22 western coastal wetlands in Taiwan, with total area 26,420 hectares. First, we reviewed literature and carried out field surveys to investigate the soil and plant carbon storage per hectare in the chosen six wetlands, which cover seven different vegetation types. Then, we applied the benefit function transfer to other 16 wetlands. The results show that the highest soil carbon storage of per hectare wetlands is 13,318 metric tons in the vegetation type of ‘mangrove', and the lowest is 408 metric tons in the ‘intertidal zones'. The CO2 stored in 22 western coastal wetlands in Taiwan was 77.6 million metric tons in total. The benefit of CO2 storage is estimated NT$232.7 billion with carbon tax, NT$15.7 billion with the carbon price from European emission allowances, and NT$252-1,352 billion with the social carbon cost. This result will provide useful information to help the public and policy makers to wisely choose whether to preserve or develop coastal wetlands.