满足城市食物消费需求的农业生产碳排放研究——以宁波为例

食物消费相关的农业生产阶段的碳排放研究,对于探讨气候变化背景下可持续消费模式的选择和低碳农业技术与管理的提升具有重要意义.以宁波市为例,采用生命周期分析与环境投入产出相结合的综合分析框架,对其2012年居民所消费食物在农业生产阶段的直接和间接碳排放进行研究,分析不同食物及不同排放源的排放特征.结果表明,粮食、猪肉、水产品和牛肉对食物消费碳排放总量的贡献最大,分别占28%、25%、10%和9%;粮食、蔬菜和蛋类单位热量和单位蛋白质的碳排放均较小,禽、蛋、水产、鲜奶单位蛋白质的碳排放低于牛羊猪肉;由农业投入品生产所带来的间接碳排放占总量的49%;化肥是多数植物性食物碳排放最大的贡献源,占植物性食物排放总量的33%;饲料是大多动物性食物碳排放的最大来源,占动物性食物排放总量的56%.为促进食物消费和农业生产的碳减排,一方面建议适当增加蛋类、水产品、禽类和鲜奶的消费比重,减少猪牛羊肉的消费比重;另一方面应着重提高农业投入品供应链的能效,推广优化施肥技术与管理,以及提升饲料品质.

Carbon emission of agricultural production associated with urban food consumption:Ningbo as a case study

Carbon emissions of agricultural production associated with food consumption is of great significance in selecting sustainable consumption pattern and improving low-carbon agricultural technology and management in the context of climate change. Using the food consumption of Ningbo city in 2012 as an example, this study examines the direct and indirect carbon emissions of those foods in the stage of agricultural production by employing an integrated Life Cycle Analysis and Environmental Input-Output approach. The emission characteristics by food categories and by emission sources are analyzed. The results indicate that, cereals, pork, seafood, and beef are the main contributors, accounting for 28%, 25%, 10% and 9% of the total carbon emissions of food consumption respectively; cereals, vegetables and eggs are all with low carbon intensity of energy and of protein, and poultry, eggs, seafood and milk have lower carbon intensities of protein than beef, mutton and pork; the indirect carbon emissions in relation to production of agricultural inputs account for 49% of the total; fertilizer is the largest emission source for most vegetal products, accounting for 33% of the carbon emissions of vegetal foods; feed is the largest emission source for most animal products, accounting for 56% of the carbon emissions of animal foods. To facilitate emission mitigation in food consumption and agricultural production, this study suggests properly increasing the consumption proportion of eggs, seafood, poultry and milk and decreasing that of pork, beef and mutton. Increase of energy efficiency in producing agricultural inputs, promotion of optimum fertilization techniques and management, and improvement of feedstuff quality are also recommended.