As more people reduce their animal product consumption for climate and other reasons, novel plant-based meat and dairy alternatives are gaining a foothold in the global food scene. Their market share is currently small, but you can imagine a future where these alternatives are commonplace in our diets. In our study, Feeding climate and biodiversity goals with novel plant-based meat and milk alternatives, we developed several alternative future scenarios of dietary changes that include more plant-based protein and assessed their contribution to environmental and socio-economic goals. Specifically, we looked at global climate, biodiversity and food security impacts of plant-based meat and milk consumption at large scales while considering the complexity of food systems through 2050.  The scenarios based on plant-based ‘recipes’ for beef, pork, chicken, and milk. The recipes were designed to be nutritionally equivalent to the original animal-derived products and realistic for existing food manufacturing capabilities and globally available ingredients (Fig 1).

We analyzed these scenarios using the Global Biosphere Management Model (GLOBIOM), an economic partial equilibrium model that integrates global agriculture, bioenergy, and forestry sectors and allows for the exploration of the potential for carbon sink and biodiversity restoration under additional land-use policy measures. We started with analyzing a reference (REF) scenario without substitution to the plant-based alternatives using country-level characteristics of food demand to project global dietary developments. We then explored the global impacts of dietary change on indicators such as GHG emissions, land use, biodiversity, food prices, and food security.

 We found that substituting 50% of animal protein consumption would substantially reduce the impacts of food systems on the natural environment by 2050 projected in the reference scenario (Fig 2). The impacts are extensive:  

• Compared to 2020, global agricultural area would decline by 12% instead of expanding.
• The decline in forest areas and other natural land would almost completely stop.
• Nitrogen inputs to cropland, as compared to 2020, would be nearly half of the reference projections.
• Water use would decline by 10% instead of increasing.
• Without accounting for any carbon sequestration on spared land, GHG emissions could decline by 2.1 Gt CO₂eq / year^-1 (31%) in 2050 (on average by 1.6 Gt CO₂eq year^-1 in 2020-2050).
• Undernourishment globally would decline to 3.6%, compared to 3.8% in the reference scenario (reducing the number of undernourished people by 31 million).

Figure 2. Change in emissions between 2020 and 2050 from agricultural and land use. Sinks from land restoration were included in the total emissions calculation. (REF) presents the distribution of emissions in the reference scenario, while (50%) presents results under the 50% global substitution scenario.

We further found that the full environmental benefit of diet shifts can be achieved if the agricultural land spared from livestock and feed production within forest biomes is restored through biodiversity-friendly afforestation. In the 50% scenario, the benefits from reduced land-use emissions without afforestation could double – a total reduction of 6.3 Gt CO₂eq year^-1. The 90% scenario would increase this mitigation potential to 11.1 Gt CO₂eq year^-1 in 2050.

The restoration of forest ecosystems would also improve biodiversity. The 50% scenario would cut future declines of ecosystem integrity in half by 2050. The restored area could contribute 13-25% of the estimated global land restoration needs under Target 2 of the Kunming Montreal Global Biodiversity Framework by 2030. The 90% scenario could even reverse biodiversity loss between 2030 and 2040.

However, impacts across regions could differ due to the differences in the population size and diets, unequal agricultural productivity, and participation in international trade of agricultural commodities. Our results show that the main impacts on agricultural input use are in China, while impacts on environmental outcomes are in Sub-Saharan Africa and South America. These regional differences could be used to design better interventions. While a global introduction of novel alternatives has the most benefits compared to the scenarios with limited product or geographical scope, regional substitution of individual products could be highly effective in achieving regional objectives, especially if combined with local strategies and purposeful selection of ‘recipes’.

While our results support the increased use of plant-based meat and dairy substitutes, it is important to keep in mind that livestock are a valuable source of income and nourishment for people in low- and middle-income countries, and have significant cultural roles, reduce risk, and diversify smallholder income. However, climate change threatens the livelihoods of these communities, requiring rapid policy and management action to avoid environmental risk and support farmers and other livestock value chain actors for a socially just and sustainable food system transition. Understanding the impacts of dietary shifts expands our arsenal of options for reducing greenhouse gas emissions and protecting biodiversity.