Applying insights from metrics on circular livestock bioeconomy systems

The use of holistic metrics is needed to understand the impacts of circular bioeconomy systems. A circular technology can result in positive outcomes for the use of an individual resource, but worse outcomes for the system overall. There is a risk of the Jevons Paradox occurring when implementing circularity in livestock bioeconomy systems. Improving the efficiency of livestock bioeconomy systems while sustaining their productivity with a reduced environmental footprint is one of the most complex and challenging problems facing livestock scientists, farmers, and the entire food supply chain today (Bilotto et al., 2024). Often, these demands are seen as two separate objectives, with many measurements and indicators specifically developed to analyze the relative trends and impacts of new approaches to address these demands. One approach that has been promoted to reduce the environmental footprint of livestock bioeconomy systems is the adoption of circular principles (Muscat et al., 2021). However, to disentangle the productivity and environmental impacts of integrating circularity in livestock bioeconomy systems, it is necessary to increase the usage of holistic metrics (Schreefel et al., 2024). By holistic metrics, we mean metrics that elucidate how the many complex processes present in livestock bioeconomy systems, from environmental to social to economic, affect each other at different scales (El Bilali et al., 2021). Holistic metrics can help define the varying impacts on livestock bioeconomy systems as a result of implementing different practices, both circular and beyond. These holistic metrics can offer insight into how different systems can be related to each other, such as how the land use ratio metric can help to distinguish the system-wide impacts of changing feed sources on feed-food competition (van Zanten et al., 2016). Another type of holistic metric can combine different categories of metrics, such as productivity and environmental impact in grams of fat-protein corrected milk over greenhouse gas emissions, to characterize system-wide impacts of changing livestock productivity (Gerber et al., 2011). However, many metrics were developed to analyze specific types of livestock bioeconomy systems and often generate results that are challenging to compare across different systems. Highly standardized metrics, such as life cycle assessment, nutrient use efficiency, or feed conversion ratio, offer results that enable comparisons but lack a holistic perspective. In this, there is a need for the continual development of robust metrics that can assess all types of circular practices (e.g. feeding food waste to livestock or biodigesters of dairy farm effluent) in order to advance the conversation of the holistic impact of circular bioeconomy systems. One example of this is the assessment framework for circular technologies, where circular livestock bioeconomy practices are compared to their linear baseline according to their economic and environmental performance in a specific context (Halpern et al., 2024). This framework allows users to compare substantially different livestock bioeconomy systems without compromising data quality or insights. This framework, while applicable to the Global South, requires significant data input that might not be feasible for widespread use globally. Still, this type of framework does not inherently include second-order system-wide impacts that can result from implementing circular practices. Here, we account for second-order impacts, such as diverting limited byproducts like food waste to animal feed, which may restrict technology adoption and cause greater environmental pollution than the byproduct’s original use (Box 1). In assessing second-order effects on circularity in livestock bioeconomy systems, it has been seen that a rethinking of how common metrics are applied, such as shifting from economic allocation to a food-based allocation in life cycle assessment, can increase insights into changing practices (van Hal et al., 2019). From this point, it is recommended to develop metrics that consider these second-order effects, for instance, through modeling. Implementing circularity in livestock bioeconomy systems must be viewed from the perspective of system-wide impacts on environmental, social, and economic dimensions. Otherwise, individual circular practices, which may be beneficial along each of these dimensions, could result in second-order effects that result in trade-offs and worse outcomes than the original practices (Box 1). In continuation of the example of food waste as a livestock feed, the limited amount of food waste generated in a system can only feed a balanced, healthy diet to a fixed number of livestock. Discounting the previous usage of this food waste (i.e., compost or incineration), the amount of benefits that could be generated in the form of food and labor production from the livestock fed food waste is also limited. Through the substitution of this food and labor into the system, there will be a system-wide benefit along the environmental, social, and economic dimensions. However, along with many similar implementations of technological solutions to systemic problems, there is an immense risk of the Jevons Paradox occurring, which is when increasing efficiency results in increased overall resource use through expanding production (Alcott, 2005). This could occur if technological benefits were used to further expand the livestock bioeconomy system production, increasing the overall environmental footprint of the sector. This risk is particularly important to recognize in these circular systems, as there is an innate limitation to the degree to which these types of circular intervention can be applied due to the limited quantity of circular inputs. Incorporating understanding of these risks is key in proper policy and governance of circular livestock bioeconomy systems. In the system Sankey diagrams (Figure 1), the following relationships exist: The corresponding width of the flows reflects the amount of resource utilization. The color of the end nodes reflects the related environmental impact of the technology (green-low; orange-medium; red-high). The length of the flows reflects the overall environmental impact of the flow of resources for use by the technologies. In System 1: Technology X and Y utilize 90 units of Resource A. The 10 unused units of Resource A have a high environmental impact. In System 2: Technology Z is introduced to utilize the unused units of Resource A. This reduces the overall environmental footprint of the system. In System 3: The Jevons paradox occurs, and Technology Z expands to utilize 20 more units of Resource A. As Technology X and Z can only use Resource A, and there is still a demand for the output from Technology Y, Technology Y utilizes 20 units of Resource B. However, the environmental footprint of Technology Y using Resource B is high, and resulting in a higher overall environmental footprint than System 1 and System 2. Sankey diagram exploring a thought experiment of circular product usage (Box 1). A full systems evaluation of circular livestock bioeconomy systems can reduce the risk of Jevons paradox occurring, such as through consequential LCAs or modeling. While circularity has been modeled at length in Europe, the potential impact of implementing circularity is missing for other regions of the world (van Zanten et al., 2023). Exploring and assessing these systems’ effects on and for other parts of the world, particularly the Global South, will be key to further progress in implementing circularity into livestock bioeconomy systems. Focusing on the similarities and differences in the roles of circularity between the Global North and Global South will greatly aid in this endeavor. Overall, it is important to use a variety of holistic metrics that explore first- and second-order effects in terms of environmental, social, and economic dimensions. However, advocating for specific circular practices based on their individual metrics without assessing the system impacts can lead to unforeseen and possibly undesirable effects. Trans- and interdisciplinary approaches are needed to understand the complexity of actions needed. Through the use of an integrated systems approach in combination with key metrics, it is possible to create sustainable and productive livestock bioeconomy systems that synergistically exist along with nature and our food systems. Clark Halpern is a PhD Candidate in the Environmental Systems Analysis and the Farming Systems Ecology groups at Wageningen University & Research. He has dual MSc degrees in Resilient Farming and Food Systems and Agroecology at Wageningen University and ISARA-Lyon, respectively, and a BSc in Environmental Science and a BA in Biology, specializing in Microbiology from the University of Chicago. His research focuses on the potential of the circular bioeconomy, where he researches the impact of changing technologies and metrics in creating the food systems of our future. He previously consulted at the World Bank Group on livestock development projects and was a Peace Corps Volunteer in Ghana (2017-2019). Tim McAllister received an MSc in Animal Biochemistry from the University of Alberta in 1987 and a PhD in Microbiology and Nutrition from the University of Guelph in 1991. He has worked as a research scientist with Agriculture and Agri-Food Canada since 1996, where he now holds the position of principal research scientist in microbiology and beef cattle production. His team has addressed a variety of topic areas related to optimizing the role of livestock in a circular bioeconomy. These include assessing and mitigating greenhouse gas emissions from agricultural systems, optimizing manure management, utilizing food loss and waste as feed, promoting food safety, and recognizing the role of grassland ecosystems in sustaining biodiversity. His team has been the recipient of numerous societal awards for their contribution to beef cattle production in North America. BarbaraAmon is an Associate Professor for Environmental Engineering and Agricultural Engineering at the University of Zielona Góra, Poland, and a Senior Research Scientist and board representative for research at the Leibniz Institute for Agricultural Engineering and Bioeconomy in Potsdam, Germany. Having had many years of practical, hands-on experience in agriculture alongside extensive research experience, she completed her habilitation in Agricultural Engineering at the University of Natural Resources and Life Sciences in Vienna in 2007. In addition to her research, she sits on many panels looking at sustainable agriculture, including the Intergovernmental Panel on Climate Change, UNEP, and the FAO LEAP partnership. She is also the Co-Chair of the Agriculture and Nature Panel as part of the UNECE Task Force on Emission Inventories and Projections and of the Expert Panel on Mitigation of Agricultural Nitrogen under the UNECE Task Force on Reactive Nitrogen. Loekie Schreefel is a postdoctoral researcher in the Farming Systems Ecology group at Wageningen University & Research. He holds a BSc in Mechanical Engineering, an MSc in Biosystems Engineering, and a PhD dedicated to regenerative agriculture. His research centers on the design, monitoring, and modeling of resilient farming and food systems, with a strong focus on regenerative agriculture. To foster on-the-ground impact, Loekie contributes his expertise as a member of the scientific advisory boards of WeAreTheRegeneration, Soil to Soul, and Regen10. Hannah van Zanten is the Chair Holder of the Environmental Systems Analysis Chair Group at Wageningen University and a visiting professor in the Department of Global Development at Cornell University. Hannah graduated cum laude from Wageningen University in 2009 with a master’s degree in Animal Sciences. Her PhD project focused on the environmental benefits of using human-inedible-sources as livestock feed. Since graduating, cum laude, for her PhD, she continued to work in this research area. With her team, she developed the circular food systems (CiFoS) model, where stakeholders can co-design and evaluate innovative yet attainable food systems that secure human and planetary health. She received several personal grants and prizes such as the NWO Talent Scheme grant and the Global FoodShot prize in 2021. This manuscript is a product of the Livestock Environmental Assessment and Performance (LEAP) Partnership. The authors would like to thank members of the secretariat for their support: Xiangyu Song (Manager), Paolo Medei (Agriculture specialist), Edoardo de Santis (Partnership specialist) and Julie Hanot, and Maud Lebeaupin (Interns). This manuscript was invited for submission by the World Association for Animal Production. The views expressed in this publication are those of the author(s) and do not necessarily reflect the views or policies of the World Association of Animal Production, the journal, the FAO or the publisher. Clark Halpern (Conceptualization, Formal analysis, Writing—original draft, Writing—review & editing), Tim McAllister (Conceptualization, Funding acquisition, Investigation, Project administration, Resources, Writing—review & editing), Barbara Renate Amon (Conceptualization, Project administration, Resources, Writing—review & editing), Loekie Schreefel (Conceptualization, Methodology, Resources, Supervision, Writing—review & editing), and Hannah Van Zanten (Conceptualization, Funding acquisition, Project administration, Resources, Supervision, Writing—review & editing) Conflict of interest statement. The authors declare no real or perceived conflicts of interest.

Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.