Carbon footprint of food : a study of sustainable food in Hong Kong

Abstract

In spite of significant public concern and discussions of the environmental impacts of food production overseas, few studies in Hong Kong have systematically compared carbon footprint (CF) associated with food supply, particularly in vegetables. This study is one of few investigations of food CF through life-cycle analysis and aims to critically evaluate the sustainability of vegetable supply in Hong Kong. Semi-structured interviews were also carried out to investigate the reasons behind Hong Kong’s vegetable supply situations and the views from food suppliers, NGOs and government department. Five types of vegetables (sweet pepper, Chinese cabbage, lettuce, water spinach and amaranth) came from four different places (Beijing, Ningxia, Guangdong and Hong Kong) were analysed and CF of vegetables was expressed in functional unit- kg CO2 e/kg (kilogram carbon dioxide equivalent per 1 kilogram vegetable). The results showed that CF of sweet pepper sourced from Beijing had the highest CF (1.011 kg CO2 e/kg), and followed by CF of lettuce and Chinese cabbage sourced from Ningxia (0.941 kg CO2 e/kg and 0.889 kg CO2 e/kg), transportation was the “hotspot” which contributed absolute highest CF among other stages (agricultural production, vacuum cooling, packaging and truck refrigeration) and accounted for 38% to 46% of the total CF of these vegetables. Comparatively, CF of water spinach and amaranth produced from Guangdong had around half of Beijing’s or Ningxia’s (0.414kg CO2 e/kg and 0.507kg CO2 e/kg). Lastly, locally Hong Kong produced water spinach and amaranth had a fraction of the CF of the above vegetables (0.020 CO2 e/kg and 0.111CO2 e/kg). Overall, the result indicated that distance plays an important role in the CF of vegetables, CF increases as the distance from Hong Kong increases. This study suggests that CF of vegetables in summer season of Hong Kong can be reduced through supplying vegetable according to seasonality and from less distant regions within mainland China. In addition, NGOs and retailers indicated that public knowledge and acceptance in sustainable food and environmentally friendly agriculture has improved a lot since the past decades but current situation of Hong Kong’s food sustainability is still disappointing as we faced a dilemma of paying extra price or sacrifice environment. Hence, cooperation between the government, NGOs and stakeholders are imperative to reshape the current food system to a decarbonized one.