“Local meat is better than imported plants” (food miles)

Production and transport are separate components

Food miles measure distance, but distance alone does not identify the vehicle, load factor, refrigeration, production system, or land-use emissions. A 2008 U.S. input-output life-cycle analysis estimated that production contributed 83% of the average household food greenhouse-gas footprint, all transport contributed 11%, and final transport from producer to retail contributed 4% (Weber & Matthews, 2008). Within that model, shifting less than one day's weekly calories from red meat and dairy to other protein sources or a vegetable-based diet reduced emissions by more than sourcing all food locally (Weber & Matthews, 2008). The result supports the stub's claim that product choice often has more influence than distance in a typical U.S. diet, not a claim that transport is negligible in every supply chain.

A global multi-region accounting study later estimated approximately 3.0 GtCO2e from food miles, equivalent to about 19% of total food-system emissions when domestic, international, and upstream transport were included (Li et al., 2022). Fruit- and vegetable-related freight contributed 36% of those transport emissions, largely because of the mass and distances moved (Li et al., 2022). The difference between the 11% U.S. estimate and the 19% global estimate reflects different geography, years, databases, and system boundaries; it does not make either percentage universal (Weber & Matthews, 2008; Li et al., 2022).

Why food category often matters more

A life-cycle meta-analysis covering 38,700 farms found up to 50-fold variation among producers of the same product, but the lowest-impact animal products typically still exceeded vegetable substitutes across the assessed environmental indicators (Poore & Nemecek, 2018). Ruminant foods have production-stage sources that transport distance does not remove, including enteric methane, manure, feed production, and land occupation (Poore & Nemecek, 2018). Consequently, proximity by itself cannot establish that local beef has a lower greenhouse-gas footprint than an imported plant food; the complete life cycle and the specific products must be compared (Poore & Nemecek, 2018).

Exceptions and reversals

Transport mode can reverse the usual pattern. A study of five fruit and vegetable commodities supplied to the United Kingdom estimated an average footprint of 10.16 kg CO2e per kilogram for fresh or chilled non-European products transported by air and distributed within the United Kingdom, 9.66 kg more than the locally produced comparison in that study (Michalský & Hooda, 2015). This supports the stub's exception for highly perishable, air-freighted products, but the estimate applies to five commodities and should not be generalized to all imported produce (Michalský & Hooda, 2015).

Season, storage, heated greenhouses, spoilage, and consumer travel can also affect a comparison, while the global food-miles model demonstrates that domestic transport can be consequential as well as international trade (Li et al., 2022). A defensible comparison therefore uses product-specific life-cycle data rather than a local-versus-imported label alone (Poore & Nemecek, 2018; Li et al., 2022).