Climate change responses benefit from a global food system approach

A food system framework breaks down entrenched sectoral categories and existing adaptation and mitigation silos, presenting novel ways of assessing and enabling integrated climate change solutions from production to consumption.

Food systems1 have not been cast effectively in either the Intergovernmental Panel on Climate Change (IPCC) or the United Nations Framework Convention on Climate Change (UNFCCC) greenhouse gas (GHG) emissions inventory guidelines2,3. Food-related emissions from agriculture, transport, industry and household consumption have traditionally been reported separately, irrespective of fundamental connections between food demand and farm-level production. Unless these are conceptualized as a unified whole, climate change mitigation and adaptation strategies associated with the food system are likely to be inefficient and possibly counterproductive.

IPCC measurement protocols form the basis of national reporting under the UNFCCC and the Paris Agreement4, and the planned global stocktake due in 2023. Yet, a food system approach could be much more useful for countries designing the next stage of their nationally determined contributions as well as for the international community by improving how climate change and agriculture are addressed in three fundamental ways5.

First, it would liberate agriculture from the ‘agriculture, forestry, and other land use’ (AFOLU) category of national greenhouse gas emissions inventories, so that the contribution of the global food system to total anthropogenic GHG emissions can be comprehensively calculated. This provides a much clearer picture of emission sources, thereby allowing for the design of more effective response options and the engagement of an expanded set of actors.

Second, a systemic approach facilitates the design of integrated adaptation and mitigation policies, which bring together supply-side (that is, crop and livestock production, processing, storage and transport) and demand-side (that is, dietary change) measures. Reducing food loss and waste as a response strategy is also best addressed across the entire food system.

Third, it provides the relevant framework to identify, analyse and address synergies and trade-offs among different climate change responses, primarily in relation to the potential competition for land to satisfy projected demand for food versus land to contribute to mitigation of climate change (through bioenergy and carbon sequestration). Relevant assessments involve the combined potential of dietary change, reduction of food loss and waste, and ‘land-sparing’ strategies that enable simultaneous food production, adaptation and mitigation activities.

Food system GHG emissions

The addition of GHG emissions from energy use, supply chains and consumption activities to those emitted within the farm gate provides a much more comprehensive depiction of how food is contributing to climate change (Table 1). The result is an overall contribution of a considerable 21–37% of total anthropogenic emissions, compared to 18–29% from agriculture combined with land-use change for food production (deforestation and peatland degradation) and ~10% from agriculture alone when defined as within-farm-gate crop and livestock production (this includes CH4 from ruminant animals and N2O from fertilizers)5,6. These current assessments, building on earlier syntheses of food systems emissions7,8,9, have significantly expanded the global analysis of key sub-components and their contributions to climate change adaptation and mitigation.

Table 1 Comparison of 2007–2016 mean values and standard deviations of emissions from AFOLU6 and global food system5 emissions by component, including food loss and waste

Food-related response options

The production, supply, and consumption of food extends far beyond farmers’ fields (and producing countries). Hence, the food system approach provides a more appropriate landscape within which policy and response actions can be analysed and implemented. Such a framework favours the link between resilience, adaptation and mitigation at scale, across landscapes and economic activities. This is achieved by complementing the more traditional supply-side responses focused on farm activities with demand-side responses that focus more broadly on consumer and industry behaviour — such as dietary change, reduction of food loss (reduction of edible food during production, postharvest and processing)10 and reduction of food waste (food discarded by consumers and retailers)10.

Dietary change

The EAT Lancet Report raised awareness of the role that dietary choices can play jointly, and thus more effectively, in addressing pressing health and climate change challenges11,12. The consumption of healthy and sustainable diets presents major opportunities for enhancing resilience (for example, through diversification), reducing GHG emissions from the food system (for example, from decreasing production of emissions-intensive animal-sourced products) and expanding climate change adaptation options (for example, by promoting sustainable agricultural management that conserves soil and water). Table 2 shows total technical mitigation potentials — the maximum amount of GHG mitigation achievable through technology diffusion — as well as total economic mitigation potentials at specified carbon prices of both crop, livestock and agroforestry activities (supply side) and dietary changes (demand side).

Table 2 Food system supply-side and demand-side technical and economic mitigation potentials5

Reduction of food loss and waste

About 8–10% of total anthropogenic GHG emissions correspond to food loss and waste5, which comprises twenty-five to thirty per cent of global food production13. Loss of edible food and food discarded by retailers and consumers create additional demand for agricultural production, thereby increasing GHG emissions and overall pressure on natural resources14. Options to reduce food loss and waste can be more easily identified, designed and assessed through a system approach — including technical measures (for example, improved harvesting, on-farm storage, infrastructure, packaging to keep food fresher longer and refrigeration) and behavioural changes (for example, acceptance of less-than-perfect fruit and vegetable appearance, redistribution of food surplus and lowered prices on nearly expired food).

Synergies and trade-offs

Adaptation and mitigation can be jointly achieved across a portfolio of practices, often with added socio-economic co-benefits (Fig. 1). For example, crop management practices such as increasing soil organic matter; erosion control; intercropping; and improved fertilizer, water, and other input management, can all increase crop production and its resilience while reducing GHG emissions. Similarly, livestock options such as better grazing land management and improved manure management contribute to both adaptation and mitigation targets.

Fig. 1: Mitigation, adaptation and co-benefits of food system responses.
figure1

Colours indicate different levels of synergy between mitigation and adaptation to climate change associated with each food system response5,20.

The identification of potential trade-offs and synergies among climate change responses is crucial to their success. A key trade-off involves competition between land use for bioenergy and carbon sequestration, to contribute to climate change mitigation, versus agricultural land use for food production. As analysed by the Agricultural Model Intercomparison and Improvement Project (AgMIP)15, bioenergy and carbon sequestration projects, especially at large scale, might encourage ‘land grabbing’ with negative trade-off effects on smallholder livelihoods and their food security16. These negative effects require parallel actions at the demand level, which can generate the needed counterbalancing ‘land-sparing’ effects. These may include, for instance, large-scale education campaigns and implementation of regulatory environments aimed at promoting dietary changes linked to more efficient and sustainable land use for agriculture.

Further, attention needs to be paid to ‘rebound effects,’ by which gains in GHG emissions efficiencies can be offset by increases in total emissions due to expansion of production linked to the increased efficiencies. Appropriate regulations and incentives, as well as monitoring systems, will need to be put in place to ensure that actual emission reductions in farming systems are taking place17.

Scaling up climate change responses

The food system approach offers significant advances for the implementation of climate change adaptation and mitigation measures. By explicitly recognizing fundamental connections between consumer demand, dietary choices and production, it favours the integration of a much broader set of actors and institutions. Yet, the scaling up of climate responses requires further research.

First, a complete accounting of food system emissions is needed. The recent IPCC Special Report on Climate Change and Land revealed that many GHG sources — such as grain drying, packaging and supply-chain emissions — are less well characterized than those accounted for in AFOLU5. Advanced remote sensing techniques can help in scaling up emissions5.

The dynamics of dietary change and their linkage to climate and health also need to be better understood. Key topics include the contribution of different measures in promoting a shift towards healthy and sustainable diets, the economic impact of such measures in regard to reduced healthcare costs, how and at what rate dietary change can lead to changes in agricultural production, and what are their social and environmental impacts.

Finally, it is essential to find actionable ways to increase adoption of key adaptation and mitigation practices, for example, rigorous testing of the role of incentives and rapid development of innovative techniques such as circular economies. Modelling and ex ante simulations of adaptation and mitigation synergies, such as done by AgMIP, can shed light on what are the potential barriers to implement specific practices, how to avoid competition between climate change mitigation and food security, and which governance structures favour equitable participation in climate change solutions.

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Correspondence to Cynthia Rosenzweig.

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Rosenzweig, C., Mbow, C., Barioni, L.G. et al. Climate change responses benefit from a global food system approach. Nat Food 1, 94–97 (2020). https://doi.org/10.1038/s43016-020-0031-z

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