Determining the primary energy demand and greenhouse gas emission of carrots : Comparing organic and conventional small scale carrot production and supply in Sweden
Sammanfattning: This study assessed the environmental performance of organic and conventional carrots produced and supplied in Sweden, as well as mapping out and describing the local carrot production and supply in Sweden to lay the roundwork for a decision support, primarily aimed at Swedish farmers and consumers. A life cycle assessment (LCA) methodology with the system boundary from carrot cultivation to consumer gate and a functional unit (FU) of 1 kg of carrots at the farm was applied, using the LCA software SimaPro 8.5.2. The information necessary for the life cycle inventory (LCI) was partially obtained from a literature review and partially from two questionnaires that were devised. Additionally, a sensitivity analysis focusing on the assumptions pertaining to the transportation has been made. The life cycle impact assessment (LCIA) focused on two impact categories: cumulative energy demand (CED) and global warming potential (GWP). The LCIA results indicated that, in the organic case, CED and GWP values were 4.45 MJ and 0.193 kg CO2 eq per FU respectively. The obtained values for CED and GWP for the conventional carrot case were 4.82 MJ and 0.216 kg CO2 eq per FU respectively. This means that the organic carrot case had less impact (about 92% in terms of CED and 89% in terms of GWP), compared to the conventional carrot case. The transportation accounted for the largest impact, especially in terms of GWP, followed by the post-harvest processes and agricultural production for the organic carrot case. For the conventional case however, the agricultural production had a larger impact than the post-harvest processes. The largest contributing factors to the impact of the agricultural production of organic carrots were identified as the plastic used for mulching and the diesel use, while the largest contributing factors for the agricultural production of conventional carrots were identified as the plastic used to package pesticides and fertilizer, the fertilizer itself, electricity use and diesel use. The largest contributing factor to the CED of the post-harvest processes was identified as the electricity use, whilst the plastic packaging had the highest impact in terms of GWP. Finally, the single largest contributing factor was identified as the transportation from retailer to household, accounting for about 84% of the GWP and 88% of the CED from the transportation stage. This is equivalent to the transportation between retailer and household amounting to about 67% of GWP and 47% of CED for the organic carrot life cycle, as well as about 60% of GWP and 43% of CED for the conventional carrot life cycle.
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