Abstract
The Paris Agreement’s goal of limiting the increase in global temperature to 1.5° or 2°C above preindustrial levels requires rapid reductions in greenhouse gas emissions. Although reducing emissions from fossil fuels is essential for meeting this goal, other sources of emissions may also preclude its attainment. We show that even if fossil fuel emissions were immediately halted, current trends in global food systems would prevent the achievement of the 1.5°C target and, by the end of the century, threaten the achievement of the 2°C target. Meeting the 1.5°C target requires rapid and ambitious changes to food systems as well as to all nonfood sectors. The 2°C target could be achieved with less-ambitious changes to food systems, but only if fossil fuel and other nonfood emissions are eliminated soon.
Generated Summary
This research, published in Science, investigates the impact of the global food system on greenhouse gas (GHG) emissions and its compatibility with the goals of the Paris Agreement, which aims to limit global warming to 1.5°C or 2°C above preindustrial levels. The study employs a modeling approach to forecast GHG emissions from the global food system, considering factors such as per capita diets, GHG intensity of food production, and global population size. The core methodology involves assessing the cumulative GHG emissions from the food system under various scenarios, including a business-as-usual trajectory and different food system changes, and comparing these emissions to the maximum allowable emissions to meet the temperature targets. The scope of the study encompasses the entire global food system, with a focus on emissions from food production and land use change. The goal is to determine if and how the food system can contribute to or hinder the achievement of the Paris Agreement’s climate goals.
Key Findings & Statistics
- The global food system emits approximately 30% of total global GHG emissions.
- Global food system emissions averaged ~16 billion tonnes (Gt) CO2 equivalents per year from 2012 to 2017.
- The cumulative business-as-usual food system emissions from 2020 to 2100 are estimated to be 1356 Gt CO2-we.
- To have a 67% chance of meeting the 1.5°C and 2°C targets, the cumulative emissions limits are 500 and 1405 Gt CO2-we, respectively. For a 50% chance of meeting the targets, the emissions limits are 705 and 1816 Gt CO2-we, respectively.
- Cumulative food system GHG emissions from 2020 to 2100 can be reduced by 14 to 48% through changes in dietary composition and healthier caloric consumption, increased crop yields, decreased food loss and waste, or through increased emissions efficiency of food production.
- Full adoption of all five strategies (plant-rich diet, healthy calories, high yields, half waste, high efficiency) could reduce cumulative emissions through 2100 by 63% relative to business-as-usual.
- Meeting the 2°C target is plausible through the use of numerous food system strategies, provided that they are also adopted by 2050.
- If full implementation of food and nonfood emission changes were to be delayed by 25 years to 2075, then even 100% adoption of all five strategies would preclude meeting the 1.5°C target.
Other Important Findings
- Reducing emissions from fossil fuels is essential, but not sufficient, to meet the 1.5°C and 2°C temperature targets; changes in the global food system are also crucial.
- Current trends in the global food system, if unchanged, would prevent the achievement of the 1.5°C target and threaten the 2°C target by the end of the century.
- Meeting the 1.5°C target requires rapid and ambitious changes to food systems, as well as to all nonfood sectors.
- The 2°C target could be achieved with less ambitious changes to food systems, but only if fossil fuel and other nonfood emissions are eliminated soon.
- The study identifies five strategies to reduce GHG emissions from the global food system: adopting a plant-rich diet, adjusting caloric consumption to healthy levels, achieving high crop yields, reducing food loss and waste, and increasing the efficiency of food production.
- The benefits of changes in the food system could include: progress towards the United Nations’ Sustainable Development Goals, such as decreased nutrient pollution, reduced water pollution and scarcity, decreased land-use change, and improved biodiversity outcomes.
- Dietary changes, such as adopting plant-rich diets, can greatly reduce emissions.
Limitations Noted in the Document
- The study relies on assumptions about future trends in per capita diets, crop yields, global population, and the GHG intensity of foods, which are subject to uncertainty.
- The analysis does not include emissions from transportation, processing, packaging, retail, and preparation, which account for a minor fraction of total food system emissions.
- The study does not account for regional variations in the adoption of different strategies, which could affect the overall impact.
- The study acknowledges uncertainties in the 1.5°C emissions limit, which could affect the timing of when emissions targets are exceeded.
- The study does not address the political, economic, or social barriers to implementing the proposed changes to the food system.
Conclusion
The research emphasizes that the global food system is a major contributor to GHG emissions and that significant changes are needed to meet the goals of the Paris Agreement. The study’s findings highlight the urgency of addressing food system emissions, as current trends are incompatible with limiting global warming to 1.5°C and could jeopardize the 2°C target. The research underscores the critical role of the food system, alongside efforts to reduce fossil fuel emissions, in mitigating climate change. Key takeaways include the need for rapid and ambitious changes, the importance of a multifaceted approach, and the potential for significant emission reductions through various strategies. The study suggests that a transition to plant-rich diets, improving the efficiency of food production, reducing food waste, and other measures could help to achieve the necessary emission reductions. The study also stresses that any delays in adopting these changes would necessitate more drastic measures later on. The conclusion emphasizes that meeting the climate targets will require a coordinated effort that addresses various aspects of the food system while also considering the needs and customs of different regions and communities. The authors highlight that addressing climate change necessitates comprehensive action in food systems alongside efforts in other sectors to stay within the emission limits and avert the worst impacts of global warming. The work provides a clear call to action, emphasizing the critical role of food systems in the global effort to combat climate change. The key message is that the window of opportunity is closing, and concerted action is required across multiple sectors to meet climate goals.