Quantifying the environmental benefits of animal-source food replacement: Integrated assessment of the environmental impact of dietary change to alternative protein sources

Abstract

The environmental impact of diets high in animal-source foods has led to growing interest in potentially more sustainable alternative protein sources, such as plant-based meat analogues, cultivated meat, insect protein, and plant-based dairy. In this study, the IMAGE Integrated Assessment Model is used to evaluate global land use, water consumption, greenhouse gas emissions and global warming for scenarios in which animal-source foods are replaced by different alternatives. The scenarios are compared to each other and to a baseline trend. The results indicate that replacing all meat by alternatives can reduce global agricultural land use by 32-39%, water consumption by 8-12%, CH4 emissions by 60%, N2O emissions by 44%, land-use CO2 emissions by 100%, and reduce global warming by up to 0.45 degrees Celsius. Replacement of milk by plant-based options can reduce agricultural land use by 6-7%, CH4 emissions by 14%, N2O emissions by 14%, land-use CO2 emissions by 44-47%, and reduce global warming by up to 0.1 degrees Celsius. Furthermore, it was shown that dietary change only in the Global North can achieve up to one third of the potential land-use and global warming reduction and up to half of the potential water use reduction of worldwide dietary change. Overall, the differences between different animal-source food alternatives are small, and a sensitivity analysis shows that small variations in the composition and resource demands of the options could change the order in which they are comparatively ranked. The main takeaway is therefore that ultimately, no single alternative is universally preferable, highlighting the need for context-specific choices to promote sustainable dietary transitions.