Potential Impact of Dietary Choices on Phosphorus Recycling and Global Phosphorus Footprints: The Case of the Average Australian City.

Changes in human diets, population increases, farming practices, and globalized food chains have led to dramatic increases in the demand for phosphorus fertilizers. Long-term food security and water quality are, however, threatened by such increased phosphorus consumption, because the world’s main source, phosphate rock, is an increasingly scarce resource. At the same time, losses of phosphorus from farms and cities have caused widespread water pollution. As one of the major factors contributing to increased phosphorus demand, dietary choices can play a key role in changing our resource consumption pathway. Importantly, the effects of dietary choices on phosphorus management are twofold: First, dietary choices affect a person or region’s “phosphorus footprint” – the magnitude of mined phosphate required to meet food demand. Second, dietary choices affect the magnitude of phosphorus content in human excreta and hence the recycling- and pollution-potential of phosphorus in sanitation systems. When considering options and impacts of interventions at the city scale (e.g., potential for recycling), dietary changes may be undervalued as a solution toward phosphorus sustainability. For example, in an average Australian city, a vegetable-based diet could marginally increase phosphorus in human excreta (an 8% increase). However, such a shift could simultaneously dramatically decrease the mined phosphate required to meet the city resident’s annual food demand by 72%. Taking a multi-scalar perspective is therefore key to fully exploring dietary choices as one of the tools for sustainable phosphorus management

Animal board invited review: Opportunities and challenges in using GWP* to report the impact of ruminant livestock on global temperature change

Ruminant livestock is a large contributor of CH4 emissions globally. Assessing how this CH4 and other greenhouse gases (GHG) from livestock contribute to anthropogenic climate change is key to understanding their role in achieving any temperature targets. The climate impacts of livestock, as well as other sectors or products/services, are generally expressed as CO2-equivalents using 100-year Global Warming Potentials (GWP100). However, the GWP100 cannot be used to translate emission pathways of short-lived climate pollutants (SLCPs) emissions to their temperature outcomes. A key limitation of handling long- and short-lived gases in the same manner is revealed in the context of any potential temperature stabilisation goals: to achieve this outcome, emissions of long-lived gases must decline to net-zero, but this is not the case for SLCPs. A recent alternative metric, GWP* (so-called ‘GWP-star’), has been proposed to overcome these concerns. GWP* allows for simple appraisals of warming over time for emission series of different GHGs that may not be obvious if using pulse-emission metrics (i.e. GWP100). In this article, we explore some of the strengths and limitations of GWP* for reporting the contribution of ruminant livestock systems to global temperature change. A number of case studies are used to illustrate the potential use of the GWP* metric to, for example, understand the current contribution of different ruminant livestock production systems to global warming, appraise how different production systems or mitigations compare (having a temporal element), and seeing how possible emission pathways driven by changes in production, emissions intensity and gas composition show different impacts over time. We suggest that for some contexts, particularly if trying to directly infer contributions to additional warming, GWP* or similar approaches can provide important insight that would not be gained from conventional GWP100 reporting. © 2023This research is supported by María de Maeztu excellence accreditation 2018-2022 (Ref. MDM-2017-0714), funded by MCIN/AEI/10.13039/501100011033/; and by the Basque Government through the BERC 2022-2025 program. Agustin del Prado is financed by the programme Ramon y Cajal from the Spanish Ministry of Economy, Industry and Competitiveness (RYC-2017-22143) and Ikerbasque. JL acknowledges funding from Wellcome Trust, Our Planet Our Health (Livestock, Environment and People—LEAP), award number 205212/Z/16/Z. FM and SH are funded by the California Air Resources Board (CARB35C10_18ISD025

Mapping phosphorus hotspots in Sydney's organic wastes: A spatially explicit inventory to facilitate urban phosphorus recycling

Phosphorus is an essential element for food production whose main global sources are becoming scarce and expensive. Furthermore, losses of phosphorus throughout the food production chain can also cause serious aquatic pollution. Recycling urban organic waste resources high in phosphorus could simultaneously address scarcity concerns for agricultural producers who rely on phosphorus fertilisers, and waste managers seeking to divert waste from landfills to decrease environmental burdens. Recycling phosphorus back to agricultural lands however requires careful logistical planning to maximize benefits and minimize costs, including processing and transportation. The first step towards such analyses is quantifying recycling potential in a spatially explicit way. Here we present such inventories and scenarios for the Greater Sydney Basin's recyclable phosphorus supply and agricultural demand. In 2011, there was 15 times more phosphorus available in organic waste than agricultural demand for phosphorus in Sydney. Hypothetically, if future city residents shifted to a plant-based diet, eliminated edible food waste, and removed animal production in the Greater Sydney Basin, available phosphorus supply would decrease to 7.25 kt of phosphorus per year, even when accounting for population growth by 2031, and demand would also decrease to 0.40 kt of phosphorus per year. Creating a circular phosphorus economy for Sydney, in all scenarios considered, would require effective recycling strategies which include transport outside of the Greater Sydney Basin. These spatially explicit scenarios can be used as a tool to facilitate stakeholders engagement to identify opportunities and barriers for appropriate organic waste recycling strategies

Shaping food environments to support sustainable healthy diets in low and middle-income countries

The global ambitions to end hunger, achieve food security and improved nutrition, and promote sustainable agriculture demand a complex transition of the current food environments for enabling sustainable healthy diets. The food environments in Low and Middle-Income Countries (LMICs) have been experiencing rapid and dynamic transitions across the globe, necessitating a system-level thinking and systemic approach to understand opportunities for improvement. There is a need for valid, reliable measures of food and nutrition environments for reorienting thinking and data collection toward determinants of food demand, especially the food environment components, which are critical to understand the transforming food systems. Food environment transformations are urgently required to provide consumers with more

Value Chains and Diet Quality: A Review of Impact Pathways and Intervention Strategies

Low and middle-income countries increasingly face a triple burden of malnutrition encompassing undernutrition, micronutrient deficiency, and excessive energy consumption contributing to overweight and obesity. Food systems are also becoming more complex, supported by investments in food processing and retailing. Traditional approaches addressing hunger, typically based on agricultural development, are deemed insufficient alone to address the problem and attention is now being directed to food value chains, although experience is currently limited. To assess the state of science and identify knowledge gaps, an integrative review of the broad topic of value chains and diet quality was undertaken, with particular focus on interventions and their related impact pathways. Interventions were classified according to their primary orientation: to increase the availability, accessibility, or desirability of nutritious food. We identified 24 separate interventions associated with 10 different impact pathways, demonstrating the numerous entry points and large potential for value chain interventions to influence diet quality. However, case study evidence regarding effectiveness remains scant. Most studies addressed individual nutrient-rich commodities that could address a nutritional deficiency in the community of interest. Rarely was overall diet quality assessed, and future studies could benefit from taking a wider perspective of dietary patterns and food substitutions. The value chain analytical approach was deemed valuable due to its consumer orientation that seeks to understand how food products are used and what motivates their choice. The systems perspective is also important as it considers the roles of actors involved in food production, distribution, marketing, and regulation. However, few studies directly engaged with the subject of the local food environment as the bridge connecting food production and food choice. The challenge is to combat the increasing prevalence of processed foods of low nutritional value through interventions that lead to nutritious food becoming more conveniently available, affordable, and desirable

A conceptual framework for modelling the role of livestock systems in sustainable diets and a sustainable planet

The role of livestock in sustainable food systems and sustainable diets is a complex issue. It should be assessed in terms of its impacts on environmental, economic, and social sustainability, as well as the levels of animal performance, the human food supply, and the human food production system. However, such nuanced analyses are made difficult by the lack of multi-metric, multi-domain modelling frameworks and a lack of data on regional variation in livestock production. This paper proposes a conceptual biophysical modelling framework that could be used as a pathway to address existing methodology gaps and improve sustainability analyses across multiple levels. Realising this modelling framework requires clear, transparent, and enforceable frameworks for multi-scale sustainability assessments, as well as long-term investment into region-specific data collection, particularly from under-represented regions. To ensure representativeness and broader utility, this framework must also be able to model variation in both production systems and consumer dietary patterns, and the feedback loops between producer/consumer decisions and on-farm production. Beyond the level of science, this will also require concerted effort by the various actors in the livestock and food-chain sectors such as governmental bodies, the food production industry and local communities. Once realised, this framework could be used to assess trade-offs between potential food-system changes and to ensure that decisions are being made from a big picture, net-benefit perspective, while exploring methods for building flexible, diverse food systems that are sustainable across multiple scales

The WULCA consensus characterization model for water scarcity footprints: assessing impacts of water consumption based on available water remaining (AWARE)

Purpose Life cycle assessment (LCA) has been used to assess freshwater-related impacts according to a new water footprint framework formalized in the ISO 14046 standard. To date, no consensus-based approach exists for applying this standard and results are not always comparable when different scarcity or stress indicators are used for characterization of impacts. This paper presents the outcome of a 2-year consensus building process by the Water Use in Life Cycle Assessment (WULCA), a working group of the UNEP-SETAC Life Cycle Initiative, on a water scarcity midpoint method for use in LCA and for water scarcity footprint assessments. Methods In the previous work, the question to be answered was identified and different expert workshops around the world led to three different proposals. After eliminating one proposal showing low relevance for the question to be answered, the remaining two were evaluated against four criteria: stakeholder acceptance, robustness with closed basins, main normative choice, and physical meaning. Results and discussion The recommended method, AWARE, is based on the quantification of the relative available water remaining per area once the demand of humans and aquatic ecosystems has been met, answering the question “What is the potential to deprive another user (human or ecosystem) when consuming water in this area?” The resulting characterization factor (CF) ranges between 0.1 and 100 and can be used to calculate water scarcity footprints as defined in the ISO standard. Conclusions After 8 years of development on water use impact assessment methods, and 2 years of consensus building, this method represents the state of the art of the current knowledge on how to assess potential impacts from water use in LCA, assessing both human and ecosystem users’ potential deprivation, at the midpoint level, and provides a consensus-based methodology for the calculation of a water scarcity footprint as per ISO 14046

Assessing the rural food environment for advancing sustainable healthy diets: Insights from India

World agricultural production has seen significant growth in the past four decades, yet malnutrition remains a persistent problem, particularly in the global south and more so in the rural areas. Need for a holistic approach to food systems is becoming crucial in designing policies that support the transition to sustainable and healthy diets. The present study is aimed to understand the rural food environment in the Telangana state in southern India by analyzing the combination of external and personal factors affecting food choices, attitudes, and consumption behavior. We developed a scoring-based methodology to assess the external and personal domains and dimensions to understand the food environment. The results showed that rural households favored carbohydrate-rich food groups obtained mostly from their own production or subsidized sources. On the other hand, protein and micronutrient-rich food groups were neglected due to affordability and preference for taste, cultural factors, and the limitations of external food environment. The findings of this study provide a deeper understanding of the food environment in low and middle-income countries (LMICs) conext. By highlighting the interplay between agriculture, food environments, and nutrition outcomes, this study contributes to the ongoing effort to address the global malnutrition crisis and support the development of healthier and more sustainable food systems. These findings can be useful to guide policy actions towards achieving food security and nutrition in the rural regions where food environments are under rapid transitions in the LMICs

Toward healthy and sustainable diets for the 21st century: Importance of sociocultural and economic considerations

Four years after the EAT-Lancet landmark report, worldwide movements call for action to reorient food systems to healthy diets that respect planetary boundaries. Since dietary habits are inherently local and personal, any shift toward healthy and sustainable diets going against this identity will have an uphill road. Therefore, research should address the tension between the local and global nature of the biophysical (health, environment) and social dimensions (culture, economy). Advancing the food system transformation to healthy, sustainable diets transcends the personal control of engaging consumers. The challenge for science is to scale-up, to become more interdisciplinary, and to engage with policymakers and food system actors. This will provide the evidential basis to shift from the current narrative of price, convenience, and taste to one of health, sustainability, and equity. The breaches of planetary boundaries and the environmental and health costs of the food system can no longer be considered externalities. However, conflicting interests and traditions frustrate effective changes in the human-made food system. Public and private stakeholders must embrace social inclusiveness and include the role and accountability of all food system actors from the microlevel to the macrolevel. To achieve this food transformation, a new “social contract,” led by governments, is needed to redefine the economic and regulatory power balance between consumers and (inter)national food system actors