Carbon footprint assessment of Myrica Rubra fresh fruit based on LCA

The carbon footprint is a measure of the CO₂ equivalent emissions directly or indirectly emitted by the production of a product over its life cycle. In the context of promoting green and sustainable development, product carbon footprint is an important indicator for assessing the environmental impact of products, which helps enterprises and individuals to formulate corresponding emission reduction measures and green development strategies. China is the origin of Myrica rubra, with a history of cultivation and utilisation dating back at least 2,000 years, which have been widely cultivated and produced in a number of regions, and have become a local agricultural speciality and leading industry.This study examined the carbon footprint of fresh Myrica rubra fruit from Huaihua, China, using the life cycle assessment method (LCA). The accounting procedure made use of the PAS 2050 and ISO 14067 carbon footprint accounting techniques. Since Myrica rubra fruit lacks designated carbon footprint of a product-product category rule (CFP-PCR), this study defines the functional unit as producing 1 kg of fresh Myrica rubra fruit based on real-world scenarios. The type from cradle to gate determines the system boundaries. The life processes of raw material acquisition and transportation, waxberry cultivation (weeding, shaping, pruning, fertilization and picking), packaging and warehousing, etc., were covered by the activity level research data that was gathered through on-site inquiry. The emission factors are obtained from the IPCC database, China Life Cycle Basic Database (CLCD), China Product Life Cycle Greenhouse Gas Emission Coefficient Database (CPCD 2.0), and publically released authoritative literature. The product carbon footprint of producing 1 kg of fresh Myrica rubra fruits in the plantation base was calculated to be 0.1853 kg(CO₂^-eq)kg⁻¹, of which the contribution of raw material acquisition, planting process, packaging and storage to the overall carbon footprint was 63.00%, 36.31% and 0.69%, respectively. Comparing the different carbon emission sources, the upstream fertiliser production and the direct emission after fertiliser application are the most important carbon emission sources for the carbon footprint of fresh Myrica rubra fruits, and the cumulative contribution can reach 91.00%, of which the compound fertilizer is 59.91% and the organic fertilizer is 31.09%. Analysing the individual carbon emission sources, it was found that the upstream compound fertilizer production contributed the most to the carbon footprint of the product (42.92%), followed by organic fertilizer production (18.56%), so the reduction and efficiency of compound fertilizer is significant to the carbon emission reduction of Myrica rubra fresh fruits, and is the key link of carbon emission reduction. Uncertainty analysis (assessing the reliability of the data and calculation process) and sensitivity analysis (assessing the impact of different system boundary settings on the final results) were conducted using the methods specified in ISO 14067, The results showed that the uncertainty of the carbon footprint accounting results in this study was small (the variation of the contribution rate was within the range of ±9%). When the activity data of the two fertilizers varied within the range of ±20%, the sensitivity of compound fertilizer was the highest (the variation of the contribution rate was within the range of −8.28% to 7.32%). The second was organic fertilizer (the contribution rate varied within the range of −5.39%~5.04%). Scientific carbon reduction strategies and recommendations have been put forth from the perspectives of raw materials, production, transportation, packaging, etc. in an effort to further lower the carbon emissions of Myrica rubra fresh fruit products and increase their competitiveness in the market. In short, the aim is to further help achieve local carbon peak and carbon neutrality goals by serving as a reference for the scientific management of greenhouse gas emissions in the waxberry sector and the development of low-carbon agriculture.