Abstract
The global food system is a significant contributor to greenhouse gas emissions that drive climate change. Animal agriculture accounts for a large share of food-system emissions, both directly and through the production of animal feed. Global population growth and rising incomes imply a further increase in demand for animal-source foods if current trends persist. Limiting global warming to the targets set by the international community will not be possible without the rapid reduction of a substantial share of animal-source foods. We show that the rapid adoption of alternatives to animal-source foods, such as plant-only diets or plant-based, cultured, or fermentation-derived analogs to animal products, can be consistent with climate goals while satisfying global demand for calories and protein. Importantly, timing is crucial: the longer the delay in adopting alternatives, the larger the share of the diet that must shift away from animal-source food by 2050 for the food system to remain within its carbon budget.
Generated Summary
This study investigates the impact of adopting alternatives to animal-source foods (ASF) on reducing greenhouse gas (GHG) emissions and achieving climate goals. The research employs a dynamic quantitative analysis of the global food industry, modeling GHG emissions under various dietary scenarios. The methodology incorporates population growth, caloric intake, and regional dietary preferences. The study focuses on the potential of plant-based diets, as well as cultured and fermentation-derived analogs to animal products, to meet global demand for calories and protein while remaining within a specified carbon budget. The core of the analysis revolves around the timing and extent of dietary transitions and their effects on cumulative emissions, with the Gompertz model used to simulate consumer adoption rates of novel food products.
Key Findings & Statistics
- The global food system is responsible for as much as a third of global anthropogenic greenhouse gas (GHG) emissions.
- Eliminating greenhouse gas emissions from livestock and allowing native ecosystems to regrow on the land currently used to feed livestock would be equivalent to a 68% reduction in carbon dioxide emissions.
- Replacing just 50% of major animal products with alternatives by 2050 is estimated to reduce land use GHG emissions by 31% compared to 2020.
- Projections lead to an estimated cumulative emissions from the food system between 2020 and 2050 of 607 GtCO2e if diets converge to 3220 kcal per person, or 639 GtCO2 if diets converge to 3515 kcal per person.
- If the goal is to keep global temperature rise under 1.5 degrees C with a 67% probability, IPCC estimates the remaining carbon budget at 1170 GtCO2e.
- Assuming the food sector continues contributing about a third of global GHG emissions, this leaves a carbon budget of 390 GTCO2e for the food sector.
- Rapid adoption of alternatives starting before 2023 with 60% of ASF replaced by 2050, rapid adoption starting 2026 with 100% of ASF replaced, will keep the food system within the 390 GtCO2e budget.
- Transition to a plant-only diet, without alternatives to ASF, must begin no later than 2025 with convergence to 100% plant-only diet by 2050 to keep the food system within 390 GTCO2e budget.
- The EAT-Lancet Healthy Diets scenario transition alone, regardless of start date, does not remain within the 390 GTCO2e budget, even with 100% convergence and fast transition pace.
- Substitution of ASF with alternatives corresponds to a reduction of global food system GHG emissions relative to the business-as-usual scenario by 33% if alternatives to ASF are used to match caloric intake, and by 31% if the replacement is with standard plant products.
- The largest increases in both total calories and in the share of calorie-dense foods are in Sub-Saharan Africa (SSA).
- For the world as a whole, the study estimates an increase in total calorie demand of 24% in 2050 compared to 2020.
- Calories from meat specifically increasing by 77%.
- Annual emissions from the global food system could double between 2020 and 2050 under a business as usual scenario.
- Replacing all animal-source foods with alternatives by 2050 without changing the composition of the average diet can reduce food system emissions from 607 Gt CO2e to 405 Gt CO2e in our benchmark scenario (a 202 Gt CO2e reduction).
Other Important Findings
- The study emphasizes the disproportionate GHG emissions from animal-source foods, highlighting that reducing reliance on these foods can drastically lower food system emissions.
- Consumer behavior in adopting new food products follows a non-linear path, with initial slow adoption followed by rapid expansion.
- The timing of the transition to alternative foods is crucial, with earlier adoption resulting in lower cumulative emissions.
- Plant-based and cultured alternatives have the potential for substantially lower emissions compared to ASF, particularly with clean energy.
- The study highlights the need to shift dietary patterns toward more plants and fewer animal products to meet climate goals.
- The EAT-Lancet Healthy Diets scenario, despite promoting healthier diets, does not keep the food system within the carbon budget due to high GHG emissions from ASF.
- The research acknowledges that the reduction of GHG emissions can be enhanced by considering the potential for carbon sequestration resulting from land restoration.
- Substantial emission reductions can be achieved by replacing ASF with alternatives or with a plant-only diet.
- Alternatives to ASF are likely the most promising path to food system sustainability.
Limitations Noted in the Document
- The study’s estimates are conservative and do not account for potential carbon sequestration from land restoration.
- Uncertainty exists regarding consumer behavior paths.
- The study focuses on caloric and protein intake and does not fully address micronutrient goals or the financial aspects of dietary transitions.
- The analysis does not incorporate the financial aspects of dietary transitions, such as the initial investment needed for alternatives to ASF, which could affect the overall cost-effectiveness of the proposed strategies.
- The analysis does not include the impacts on land use and degradation, water depletion and pollution, and biodiversity loss, which are also important environmental considerations.
Conclusion
The research underscores the critical role of dietary shifts, specifically the adoption of alternatives to animal-source foods, in achieving global climate goals. The findings emphasize that relying on business-as-usual practices, which include rising consumption of animal-source foods, will make it impossible to meet the emission targets set by the international community. The study’s key insight is the importance of the timing of the transition: delaying the adoption of alternatives will necessitate more extensive shifts away from animal-source foods to meet the same carbon budget. The success of alternatives hinges on their ability to match the attributes of animal products, primarily price and taste, which will drive consumer acceptance and large-scale adoption. The models used for consumer adoption dynamics reveal that early action is critical to minimize the cumulative GHG emissions. The study projects that replacing animal products with alternatives or plant-based diets can significantly cut emissions. The research also points to the need for strong policy interventions to support the adoption of alternatives to ASF. These interventions should mirror those that fostered the growth of alternative energy sources. Such measures include financial incentives, research grants, and regulatory support to improve the quality and affordability of alternatives. The focus on consumer behavior models, rather than emission reduction scenarios, underscores the practical relevance of this analysis. The study concludes by emphasizing that the shift to alternatives is not just a technological or environmental imperative, but also a strategic one. By emphasizing consumer preferences and market dynamics, the research outlines pathways towards a sustainable food system. This approach, which focuses on what consumers are willing to accept, offers a practical strategy for aligning food production with the goals of climate change mitigation. This focus, combined with reducing waste, will yield the most impact on the food industry emissions, and the planet as a whole.