Is local food more environmentally friendly? The global GHG emissions impacts of consuming imported vs. domestically produced food
With the increased interest in the ‘carbon footprint’ of global economic activities, civil society, governments and the private sector are calling into question the wisdom of transporting food products across continents instead of consuming locally produced food. While the proposition that local consumption will reduce one’s carbon footprint may seem obvious at first glance, this conclusion is not at all clear when one considers that the economic emissions intensity of food production varies widely across regions.
In this paper we concentrate on the tradeoff between emissions associated with the production of food, on the one hand, and those associated with food transportation, on the other. Specifically, we test the following hypothesis: Substitution of domestic for imported food will reduce the direct and indirect Greenhouse Gas (GHG) emissions associated with consumption.
We employ an enhanced version of the GTAP model of global trade, production and consumption. This version accounts for greenhouse gas emissions from all economic activity in all sectors of the economy. Special attention is paid to non-CO2 GHGs which are disproportionately present in the farm and food system. We explore the impacts of shifting consumption from imported to domestically produced food products using a household consumption tax on imports.
We focus first on ruminant livestock, since it has the highest emissions intensity across food sectors, but we also consider other food products as well. We find that variations in regional ruminant production emissions intensities have profound implications for the food miles debate. While shifting consumption patterns in wealthy countries from imported to domestic livestock products reduces GHG emissions associated with international trade and transport activity, we find that these transport emissions reductions are swamped by changes in global emissions due to differences in GHG emissions intensities of production. Therefore, diverting consumption to local goods only reduces global emissions when undertaken in regions with relatively low emissions intensities. For non-ruminant products, the story is more nuanced. Transport costs are more important in the case of dairy products and vegetable oils.
Overall, domestic emissions intensities are the dominant part of the food miles story in about 90% of the country/commodity cases examined here. Therefore, with a few exceptions, one can predict the consequences of a food miles policy simply by comparing the home region’s ruminant meats emission intensity with the import-weighted average the production intensity in the rest of the world.