A bottom-up approach to model the environmental impact of the last-mile in an urban food-system

Addressing urban consumption and the inherent environmental impacts is considered indispensable for climate change mitigation. However, city-specific insights in urban food-systems are often missing. This study uses a novel bottom-up approach to evaluate the environmental impact of the last-mile of consumers within the food-system. Primary data was gathered by means of a survey (N = 663) to model the last-mile, which was combined with secondary data sets, largely from regional studies. Jointly, they informed our hybrid Urban Metabolism -Life Cycle Analysis (UM-LCA) model. This model allowed us to assess the likely environmental impacts of the food-system on global warming, freshwater quality and land use, in relation to urban food consumption behaviour. In our case study, we found that last-mile movements of consumers account for as much as 5.3-5.8 percent of the food-system?s total global warming potential. This is a considerable share, especially in proportion to the impact share of all other transport for distribution in the system (11.5-15.6 percent). This is a result of the numerous shopping trips, and while the majority of visits is almost equally shared by motorized and active modes, the vast majority of kilometres for the last-mile is travelled by motorized modes (68.2 percent). Furthermore, interesting differences could be found between city districts in terms of transport modes used by households resulting in different last-mile impacts, which is relevant to explore further for potential policy interventions to stimulate active modes. Food will inevitably get on the urban agenda, and therefore it is important to gain city-specific insights in relation to urban food consumption and its impacts. This study confirms that the influence of consumer choices is considerable and therefore it is worth further mapping these to develop adequate sustainability strategies. We argue that the bottom-up approach provides for both a measuring and monitoring tool, as well as an evaluation tool of urban policy and design towards more sustainable food systems. (C) 2020 Published by Elsevier B.V. on behalf of Institution of Chemical Engineers.

Automated summary

This study evaluates the environmental impact of consumer activities at the end of the food system through a novel bottom-up approach. The research finds that last-mile movements of consumers account for 5.3-5.8% of the total global warming potential of the food system. Additionally, differences in transport modes used by households in different city districts result in varying last-mile impacts.