Substituting Meat for Plant-Based Alternatives To Cut Global Emissions

If we switched half our meat and milk products to plant-based alternatives, global greenhouse gas emissions (GHG) could fall by up to 31% by 2050, new analysis suggests. A 50% substitution scenario could also reduce water usage and undernourishment levels significantly. The research is published in Nature Communications.

Plant-based foods: more than a novelty?

The recent rise of plant-based alternatives means it’s a good time to be a vegetarian ‒ but could it be a good time for the planet as well?

Plant-based meats (PBMs) are made from mycelium, plants or other non-animal sources in such a way that their taste and texture resemble that of animal meats. Since these products do not rely on traditional animal agriculture – which is responsible for a significant portion of global GHG emissions – many researchers are now beginning to wonder whether the wider adoption of these products could have a positive impact on sustainability and climate goals. 

“Livestock products contribute about 60% of emissions in the food system, and the food system is one-third of global emissions, so reducing these emissions matters for the climate,” Eva Wollenberg, a research professor at the University of Vermont and an author of the new research, told Technology Networks. “Land use is the next major emitter and agriculture is the largest driver of emissions in the land use sector.”

“PBMs have been viewed as a novel food largely limited to urban buyers and restaurants,” Wollenberg continued. “When viewed for their potential global impacts on land use, PBMs can have significant impacts on GHG emissions  and other ecosystem benefits, without reducing food security.”

Current estimates suggest that plant-based milks already make up 15% of the total American milk market, with plant-based meats making up 1.4% of the meat market. In this latest study, the researchers considered what the environmental and food security impacts might be if 50% of the current animal product market – which includes pork, chicken, beef and milk – were to be substituted by plant-based products.

GHG emissions, deforestation and water use could fall significantly

The latest research was based on generic plant-based beef, pork, chicken and milk recipes provided by a leading plant-based food producer, Impossible Foods. The researchers were able to realistically model to what extent a dietary switch to plant-based alternatives would have on food manufacturing and globally available production ingredients. Impossible Foods had no part in the decision-making process for this peer-reviewed study.

Based on this alternative recipe data, the researchers constructed a range of forward-looking scenarios of different dietary changes until 2050. These were analyzed using the Global Biosphere Management Model (GLOBIOM) to explore the impacts of these new dietary habits on GHG emissions, land use, food security and other relevant outcomes.

Compared to 2020, they found that a 50% substitution of meat for plant-based alternatives could result in:

• A 31% decline in GHG emissions, equivalent to around 1.6 gigatons per year on average between 2020 and 2050.
• A 12% decline in global agricultural land area.
• Halting of declines in forest and other natural land areas.
• A 10% reduction in water use.
• A fall in global undernourishment from 3.8% to 3.6%, equivalent to approximately 31 million people.

The researchers also calculated that if additional GHG savings due to land use changes (e.g., tree planting on unused agricultural land) were factored in, the planet could expect to see GHG emission reductions of around 6.3 gigatons per year by 2050.

“The resulting spared land provides an opportunity for increased biodiversity, ecosystem integrity and carbon storage, potentially doubling the mitigation impact,” Wollenberg said. “It would require policy measures however, to ensure that the land is used in a way that offers these benefits.”

“While the scenarios here are aspirational, they expand our vision of what is possible, and that our food systems do not have to be locked in to diets of overconsumption of products that harm the planet,” she added.

Further analysis still needed

While these results do support the more widespread adoption of plant-based alternatives, the authors do note several other factors that must be considered when looking at this work.

For instance, such a major shift in diet is likely to have varying impacts when comparing global regions. It is also important to recognize that livestock are a valuable source of income for many communities in low- and middle-income countries, in addition to having significant roles in local culture. Climate change is already increasingly putting these livelihoods at risk, and so any major shifts to make the global food industry more sustainable must be careful to not leave these groups behind.

“To understand the potential for expansion, [we] need more business case analyses and market studies in different regions of the world,” Wollenberg said.

Consumer behavior is another important aspect that must be considered when it comes to plant-based products.

“We do not know the rate of displacement of meat associated with PBMs,” Wollenberg noted. “It is possible [consumers] will supplement, rather than substitute, for existing meat consumption.”

Reference: Kozicka M, Havlik P, Valin H, et al. Feeding climate and biodiversity goals with novel plant-based meat and milk alternatives. Nat Commun. 2023. doi: 10.1038/s41467-023-40899-2

Eva Wollenberg was speaking to Alexander Beadle, Science Writer for Technology Networks.