Achieving Global Environmental Goals Through Plant-Based Food
The global food system is unsustainable, partly because of the mass consumption of animal products. The consumption of red and processed meats also has an adverse effect on public health in both high- and low-income countries. While the growth of “flexitarianism” is encouraging, promoting a mass dietary shift away from animal consumption remains challenging.
Whereas research consistently shows the local environmental benefits of plant-based eating, few studies have explored the impacts of large-scale alternative protein adoption. This study uses computer modeling to evaluate how a worldwide shift to plant-based alternatives would change the environmental impact of global food systems.
The authors chose a global economic land use model that would simulate global agriculture, bioenergy, and forestry sectors. With this model, they developed different scenarios to explore what would happen if we replaced varying percentages of animal-source foods (like cow meat, chicken meat, pig meat, and milk) with alternative plant-based products through 2050. These scenarios allowed them to examine how such dietary changes could influence GHG emissions, deforestation, and other environmental aspects on a global scale.
When developing their models, the authors chose plant-based products that would be appealing to the general public as well as nutritionally identical to the animal products they replaced. Furthermore, they made sure the ingredients would be feasible to produce within our current global manufacturing and production capabilities.
The study considered different substitution rates, regional variations, and alternative recipes for these novel food products. The authors also investigated whether the dietary shifts could have a rebound effect, where lower demand in one region might lead to lower prices and increased consumption in other parts of the world. They explored the impact of these changes on food security, land use, and biodiversity. The aim was to provide insights into how transitioning to more sustainable diets could help mitigate climate change and support biodiversity conservation, while also recognizing the complex challenges and regional differences involved in such a transformation.
The results of a “business-as-usual” scenario show an increase in global food demand through 2050 primarily as a result of higher incomes and larger populations. Consumption of animal products would increase, with chicken increasing by 38% and milk by 24%, as would demand for crops utilized to feed animals used for food. Land use emissions would increase by 15%. In this business-as-usual situation, higher incomes might lead to improved food security and reduce undernourishment — but only if climate change does not significantly impact global food systems between now and 2050.
In the alternative scenarios, the authors gradually substituted projected animal-based consumption with plant-based alternatives. They found that some plant-based recipes were more economically competitive than others, especially when less meat and dairy were replaced. Total demand for most crops decreased compared to the business-as-usual scenario. The lower demand led to price reductions for food staples and higher food availability, in turn improving food security. These changes would prove significant by 2050 even if plant-based alternatives were substituted at rates of only 25%.
Taking various models of plant-based adoption into account, the study demonstrates that substituting 50% of meat and dairy with novel alternatives could lead to profound impacts in the global food system. Land use emissions would decline by 31%, largely because of methane reductions. Increasing plant-based substitutions beyond 50% could further reduce deforestation and emissions, but only slightly. This is because substituting 50% of meat and dairy would effectively eliminate the land use change driven by animal agriculture.
Further, the 50% scenario could mitigate some of the unequal impacts of climate change. For instance, China could have 25% more abandoned cropland, which would offer opportunities for reforestation. Sub-Saharan Africa could see reductions in forest and natural land loss. Although Sub-Saharan Africa, Brazil, and other South American countries would only consume 22% of plant-based meat in this scenario, they would contribute a 51% reduction in global GHG emissions by 2050.
One major issue leading to the minimum 50% adoption of novel alternatives is cost, as currently plant-based meat and dairy substitutes are more expensive than animal products. However, the authors point out that the industry intends to reach price parity as soon as 2024. The authors suggest that governmental policies would play a critical role in encouraging a speedy transition to novel alternatives. As people make the switch to plant-based food, progressive policies will also be needed to support conservation and carbon sequestration on abandoned agricultural land.
The study does have limitations. For instance, the global land use model utilized by the authors emphasizes agriculture, forestry, and bioenergy, but not other industries potentially relevant to global food systems. The study also does not consider the production costs of novel alternatives outside of crop ingredients or the quantity of animal products that would need to be substituted with vegetable oils. And, while the recipes constructed were designed to match the nutritional profiles of animal products, they could not account for regional variations in calorie content.
All in all, the data is clear: opting for plant-based alternatives to meat and dairy on a global scale is a promising step toward mitigating climate change and environmental destruction.
https://doi.org/10.1038/s41467-023-40899-2