Carbon Footprint ausgesuchter gartenbaulicher Kulturen im Rahmen eines Pilotprojektes zur neuen PAS 2050-1 - Bewertung der Treibhausgasemissionen entlang der Wertschöpfungskette

Carbon Footprint of selected horticultural crops in the context of a pilot project for the new PAS 2050-1 Assessment of greenhouse gas emissions along the value chain Dissertation: Florian Schafer, Institute of horticultural science, University of Bonn The objective of this study is an assessment of greenhouse gas emissions of asparagus, rhubarb and strawberries grown in Germany under different cultivation methods with the aim of earlier harvesting of the crops. For asparagus and rhubarb the use of a soil heating system was assessed in order to compare it with an unheated cultivation. Field grown strawberries were compared with those cultivated under plastic tunnels. In addition an assessment of imported asparagus from Peru by ship and cargo aircraft with the specific Land Use Change (LUC) for Peru was carried out. Biogenic Carbon was included and excluded in the results to show both approaches and the impact on the carbon emissions of horticultural products. The results of the study were a significant part of the pilot project for testing the new PAS 2050-1 Standard, which gives specific guidelines for estimating the carbon emissions of horticultural products. For the calculation, mainly primary data obtained from interviews with the farm managers over three cultivation periods were used. These were supplemented by specific secondary data identified within a desk review. The carbon footprint up to the farm gate was calculated using the PAS 2050-1 (2012) for horticultural products and up to the consumer use phase the PAS 2050:2011 was applied. For asparagus, it emerged that the soil heating system led to a worse carbon footprint within the assessed asparagus cultivation systems due to the amount of plastic and energy required to operate the hot water pumping system. Similarly for rhubarb, where it was the high plastic content of the heating tubes which led to the worse carbon footprint in comparison to the unheated rhubarb cultivation system. The energy required for heating the water for both heating systems was not taken into account because this energy has already been included. The strawberries grown under Haygrove tunnels also had a higher carbon footprint than the field grown strawberries. Asparagus imported from Peru by ship had a much better carbon footprint than that imported by air. When considering the carbon emissions of the horticultural crops throughout the whole life cycle up to the consumer use phase, it turned out that the Product Carbon Footprint (PCF) was influenced up to 50% by the consumer. The use phase with shopping tour, storage in the domestic refrigerator and preparation of products except the asparagus grown with a heating system was in total more than 50% of the PCF. Possible carbon dioxide savings were determined for all crops using the results of the study. For growers there is the possibility of reducing nitrogen fertilization to the optimum, or the use of more durable materials instead of thin plastic foils or tubes for the heating system or irrigation. The consumer could reduce the PCF substantially by handling the product in the life cycle stage he controls in a more climate friendly way. Substituting an environmentally harmful private car by a carbon neutral bicycle, and consuming immediately without a refrigeration period at home could reduce the PCF by up to 50%. Finally recommendations for the reduction of the carbon footprint were given for both growers and consumers. Inhaltsverzeichnis Seite VI