Discussion and conclusions

emission savings are positively related to agricultural production staying within the EU due to its assumed higher emission efficiencies. However, additional emissions from transportation and deforestation related to imported protein feed, that are not captured in our results, could counteract those savings. Even if emissions are reduced in all food waste scenarios compared to the Baseline, it might be questionable whether a policy-induced increase in EU pig production is desirable in the light of pursued sustainability targets (Sandström et al., 2018). Thus, the actual design of policies steering the reuse of food waste, interrelating policies (e.g., regulations on feed imports (Karlsson et al., 2021)), costs for farmers, and the available food waste biomass will influence the overall sustainability outcome of such interventions.

order of their implementation (Papargyropoulou et al., 2014) and the actual interpretation of policy targets. It is an ongoing debate whether valorizing surplus food as animal feed contributes to food waste reduction (e.g., Goossens et al., 2019). The UN SDG 12.3 target to halve food waste refers to uneaten food that “goes to destinations other than animal feed or bio-based materials/ biochemical processing” (Champions 12.3, 2017). Since also the reduction of inedible food parts is envisaged (Champions 12.3, 2017), making increasingly use of valorization options like reuse as animal feed may be necessary to reach this goal.

Some researchers state that only inedible, unavoidable fractions should be valorized (Corrado et al., 2020; Van Zanten et al., 2019). Given that large parts of the arising food waste at the consumption stage are counted as avoidable, it remains questionable whether unavoidable parts represent a sufficient amount for setting up a competitive valorization system. The assessment of our FWfeed scenario reveals that valorizing even all available plant-based food waste biomass is limitedly competitive and environmental benefits are small compared to halving all avoidable food waste occurring at consumption stage. Our valorization scenario is only limitedly comparable to existing studies. We focus on integrating available food waste in the pig diet whereas existing analyses (Röös et al., 2017; Schader et al., 2015) assess scenarios in which animals are only fed by valorized food waste and other ecological leftovers. These studies implicitly restrict animal production and thus result in stronger environmental benefits than in our analysis of a somewhat more likely setting.

3.5.2 Potential non-accounted effects

According to our scenario results, halving avoidable EU consumer food waste decreases agricultural production to a considerable extent abroad, whereas the valorization of food waste as animal feed increases demand for protein-rich feeds such as soya to balance pig dietary requirements.

Environmental impacts from land conversion have not fully been accounted in this assessment such as potential deforestation related to increased feed demand (Escobar et al., 2020; Karlsson et al., 2021). Emission savings from the valorization as animal feed could therefore be smaller than our findings

suggest or even negative. In contrast, emission savings related to halving avoidable consumer food waste might be even underestimated as also unaccounted emissions might be saved due to the declined food demand.

Applying a PE model, we do not fully account for rebound effects.

Consumers may use expenditure savings to consume higher value, non-food products (Kuiper and Cui, 2020; Philippidis et al., 2019) which might offset the agricultural emission reductions. Saved emissions from reduced incineration or landfilling of food waste (Birney et al., 2017) are neither accounted for in our analysis. Also, we do not consider compliance, opportunity, or policy implementation costs (De Laurentiis et al., 2020).

Costs and emissions related to setting up a food waste handling, collection and treatment system in order to valorize food waste as animal feed (Spinelli and Corso, 2000) are roughly captured in the price sensitivity analysis. In our analysis we abstract from implications related to the choice of food waste treatment technology and intra-annual fluctuations regarding the amount and composition of available food waste. Since FWF is complemented with conventional feed to fulfill nutrient requirements of pig diets in the model, we do not assume a deterioration of meat quality. We do not account for potential differences in the willingness to pay for pork produced with FWF (Kurishima et al., 2011). The national average consumers and producers in the model are represented as rational, economic agents and their behavior is calibrated based on historic data. Heterogeneity in food intake, waste, or rebounds (Chitnis et al., 2014) between consumers is beyond the scope of this analysis. At country level we account for a potential link between affluence and food waste behavior. However, the validity of this relationship is subject to ongoing discussions (UNEP, 2021) and requires further research (Appendix C). Except for food waste-related behavior, preference changes toward more sustainable consumption and production choices are not accounted for in our analysis. Considering diets shifting increasingly toward plant-based choices (Saari et al., 2021), other valorization options for food waste than the reuse as animal feed, such as the production of fertilizers (Slorach et al., 2019), could become increasingly relevant. While our results are specific to the EU agricultural-food market, the intervention logic and the direction of effects could be transferrable to other large high-income regions.

3.5.3 Sustainability tradeoffs and policy implications

If we combine both interventions in the FWcombi scenario, our model projects the largest EU agricultural emission savings of our scenarios (4%).

By accounting for market and trade feedbacks, we find additional emission savings abroad as consequence of such a considerable decline in EU demand, whereas the valorization of plant-based food waste as pig feed promises comparably small environmental benefits.

The consideration of market feedbacks results in lower environmental benefits from food waste reduction and valorization within the EU compared to the embedded impacts in the previously wasted food. Globally however, our assessment shows that reducing avoidable consumer food waste might achieve an over-proportional reduction of GHGE due to considered regional differences in emission-efficiencies of agricultural production. Given the global nature of the problem, GHGE reductions contribute to climate change mitigation wherever they are achieved. In contrast, the described trade feedbacks limit the reduction of local environmental pollution like nitrogen surpluses. Therefore, complementary production-side interventions could be implemented to achieve environmental improvements “domestically”.

EU food waste reduction and valorization lead to lower food prices across product groups which facilitates food access for net consumers, also in low-income trading-partner countries. However, for consumers who already exceed recommended intake levels of some foods (Mertens et al., 2018), this can have undesirable impacts on nutrition.

Trade effects resulting from potential EU consumer food waste policies can cause increases in exports and competition for producers abroad. Overall, the reduced food demand related to a reduction in food waste negatively affects the income of net producers in the EU — and via trade effects also elsewhere.

If FWF is available at low costs, this can be beneficial for pig farmers.

However, policy-makers need to consider that FWF appears only limitedly competitive compared to conventional feed due to its assumed low protein content and could therefore require subsidization unless a price premium is expected for circular pork. Furthermore, if FWF is available at a

competitively low price, EU pig production might increase. This, accompanied by additional demand for imported protein feed, could offset intended environmental improvements. Our results question whether available plant-based food waste biomass would suffice for setting up a competitive valorization system for pig feed. If this is politically intended, potential benefits should be pre-assessed subject to valorizing only unavoidable food waste and a declining demand for animal products to not compromise other policy aims.

The described tradeoffs will, to some extent, be inevitable in the transformation to a more sustainable EU food system. These tradeoffs must be accounted for in any food waste policy implementation to make these attempts a success across sustainability dimensions. This includes the consideration of additional policies that 1) account for indirect income effects for producers in the food chain in and outside the EU, 2) steer consumers toward compliance with dietary recommendations, 3) avert additional imports of emission-intensive protein feed, and 4) ensure that food waste policy packages are coherent to prevent the creation of unintended competition for food waste biomass.

Acknowledgments

This paper benefitted from discussions in the Expert Panel of Nitrogen and Food of the Task Force on Reactive Nitrogen under the Working Group on Strategies and Review of the UNECE Convention on Long-range Transboundary Air Pollution where CL, AP, AL and HvZ have been members. TH acknowledges the support by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany’s Excellence Strategy - EXC 2070 – 390732324.