Protein versus global warming potential – a meta-analysis of the global warming potential and protein ratios for human food
The poster presented at 10th International conference on Life Cycle Assessment of Food 2016, Dublin illustrates the results of a meta-analysis of LCA studies to identify the Global Warming Potential (GWP)/protein ratio for a range of human foods. Attempting to identify what foods offer the highest amount of protein, for the lowest GWP as 1) identifying alternate protein sources is cited as a key reasons limiting a shift away from a high meat based diet, and 2) Previous comparable studies identify a limited range of food types with respect to the diverse range of possible protein alternatives.
The results were generated by expanding on Clune et al.’s meta-analysis of LCA studies to identify the GWP of 98 raw food types with a protein value higher than 3g/100g. These LCA figures were amended to enable a comparative figure for raw food with minimal packaging at the regional distribution centre. The GWP values were then divided by protein figures for raw food provided by the US dietary website. This created 88,994 GWP/protein scenarios which where statistically analysed.
The results of the paper indicate: 1) findings are generally consistent with the hierarchy identified in other papers that legumes and cereals offer the most satisfactory GWP/Protein ratio followed by non-ruminants, and then ruminants, 2) a very large diversity of results occurs between fish species, 3) Processed vegetarian meat alternatives were comparable with some non-ruminant meats, 4) the variation of results within individual food types in some categories is often high, and could be biased if you decided to cite only a limited number of LCA studies, 5) LCA studies are biased towards particular food types, many of the high protein/low GWP foods types have a low number of LCA studies identified, and would benefit from further attention given there potential role as a protein source in sustainable human diets.
Overall, the study provides a broader range of results for the GWP/protein ratio than previous papers to assist in informing sustainable human diets. The results also illustrate food types where limited LCA studies have been completed.
The abstract and poster are available for download below.
Abstract and poster
Clune, S. (2016) Protein versus global warming potential. Presented at 10th International Conference on LCA of Food 2016, Dublin
19th of October 2016