Cradle-to-cooked-edible-meat analysis of greenhouse gas emissions

Abstract

This study aimed to synthesize mean cradle-to-cooked-edible-meat greenhouse gas emission factors for bovine, ovine, pig, and poultry meat through a systematic review process. 64 studies involving 42 countries/regions, published between 1997 and 2015 were identified meeting selection criteria using Cochrane search strategies. Major emission activities were identified and synthesised into a cradle-to-cooked-edible-meat lifecycle system. 270 emission factors were identified from publications and taken as baselines. 67% baseline evaluation boundaries stopped at farm-gate, only 3% at home/restaurants. Baseline emission gaps were identified by comparing baseline evaluation systems against the synthesised system. Emission factors for major activities were identified from publications and mean values were used to fill emission gaps in order to obtain the cradle-to-cooked-edible-meat emission factors, which were then grouped to obtain a mean cradle-to-cooked-edible-meat emission factor for each meat type. Mean emission factors (kg CO₂-eq/kg) for adjusted cradle-to-cooked-edible-meats were: Bovine 61.3 (n = 124), Ovine 61.2 (n = 38), Pig 15.8 (n = 56) and Poultry 9.4 (n = 52), which are significantly higher than the adjusted means for carcass at regional-distribution-centre: Bovine 23.9 (n = 118), Ovine 23.3 (n = 9), Pig 5.0 (n = 51) and Poultry 3.6 (n = 45); or the adjusted means for saleable meat at retail: Bovine 32.3 (n = 122), Ovine 31.2 (n = 36), Pig 7.9 (54), and Poultry 4.2 (n = 50). This study confirmed current meat emission evaluations reflect only a fraction of dietary impacts. Emission factors for cooked-edible-meat could be three times the amount of meat commodities at farm-gate. Emission factors vary significantly within and between meat types.