The global agrifood system faces increasing pressure due to its heavy reliance on non-renewable energy and resources. While agricultural intensification has boosted productivity, it has also led to significant environmental impacts, exceeding planetary boundaries. Transforming the agrifood system is crucial for sustainability, with livestock systems playing a central role in this transformation. Reducing reliance on fossil fuels, optimizing land use, and improving food distribution are key objectives. Grazing agroecosystems, often perceived as more sustainable alternatives, are increasingly integrated into the global agrifood system. However, their economic viability is often challenged by competition from intensive livestock farming. The Common Agricultural Policy (CAP) in the European Union aims to support rural areas and maintain the profitability of these systems through direct payments and rural development programs. While the economic role of the CAP is frequently considered in socio-economic analyses of grazing systems, its environmental implications are less well-understood. This study addresses this gap by assessing the effect of CAP on the sustainability of grazing agroecosystems using a systems ecology and thermodynamic perspective.

Existing research highlights the increasing energy and material demands of the agrifood system, particularly its reliance on fossil fuels. Studies using national or regional datasets have shown improvements in agricultural efficiency but also a greater use of non-renewable resources, often resulting in stagnant or declining sustainability. Previous research on grazing agroecosystems emphasizes their potential to mitigate some of the negative impacts associated with intensive livestock production, particularly when managed sustainably, using local renewable resources. However, many studies have not comprehensively considered the influence of public agricultural policies, specifically the CAP, on the sustainability of these systems. This paper seeks to rectify this by applying an emergy accounting approach to explicitly incorporate the economic flows and their embedded energy and resources.

This study utilizes Emergy Accounting, a systems ecology and thermodynamic approach, to analyze the sustainability of mountain grazing agroecosystems in three valleys of the Spanish Pyrenees over three decades (1990, 2004, and 2018). Data were collected via face-to-face surveys of 50 cattle farms. Emergy Accounting considers all energy and material inputs, differentiating between renewable/non-renewable and local/imported sources. The emergy of each input is calculated by multiplying the amount of the input by its transformity (solar emergy joules per joule, sej/J, or Unit Emergy Value (UEV) if expressed in mass, currency, etc.). The total emergy supporting the system is the sum of all emergy inflows. Several emergy indicators were calculated (Table 1), including renewability, emergy yield ratio (EYR), emergy investment ratio (EIR), emergy exchange ratio (EER), environmental loading ratio (ELR), and emergy sustainability index (ESI). The Source Diversity Index (SDI) was also used to assess system resilience. The study compared the evolution of these indicators over time and across different farming trajectories previously identified, examining the role of the CAP in shaping the sustainability of the agroecosystems. Statistical analysis (ANOVA and Kruskal-Wallis tests) was used to analyze differences between years and trajectories.

The study revealed a decrease in the proportion of emergy from animal feeds, crop inputs, and labor from 1990 to 2004, coinciding with a shift from dairy to beef production. Conversely, the relative contribution of CAP payments, services, and other inputs (machinery, buildings, energy) increased significantly during this period and remained relatively constant thereafter (Figure 2). The relative contribution of local natural resources decreased over time. Analysis of emergy indicators showed a decrease in the proportion of renewable resources, a reduced contribution to the socioeconomic system, and a significant decline in sustainability from 1990 to 2004 (Figure 3). The dependence on market inputs and the environmental load increased. Market trade status showed uneven exchange, but CAP payments improved this over time. While farms followed different evolutionary trajectories, their overall sustainability performance remained within similar thresholds (Figure 4). The Source Diversity Index (SDI) showed a significant decrease in the diversity of input sources from 1990 to 2004, mainly due to increased reliance on CAP payments (Table 2).

The findings reveal contrasting trends at local and global levels. Locally, farms increased the use of renewable resources by extending grazing periods and reducing purchased feeds. However, this positive local trend was overshadowed by the increased dependence on the broader socio-economic system, largely driven by the CAP. The CAP payments, while ensuring economic viability, masked the environmental cost of the resources embedded in these payments, reflecting the unsustainability of the overall economic system. The study highlights the complex interplay between local farming practices and the broader socio-economic system, emphasizing that local sustainability cannot be achieved without addressing the larger systemic issues of resource consumption and economic structures. The increasing concentration of input sources, particularly the reliance on CAP payments, potentially reduces the resilience of the farming systems.

This study demonstrates that despite shifts towards locally sustainable practices within mountain grazing agroecosystems, the increased dependence on CAP payments and the broader socio-economic system ultimately undermines their overall environmental sustainability. The study underscores the need for policies that promote both economic viability and true environmental sustainability, moving beyond simply subsidizing unsustainable practices. Future research should focus on developing more effective policies that incentivize truly sustainable practices while considering the complex interactions between local systems and the broader global economy.

The study focuses on a specific region of the Spanish Pyrenees and may not be fully generalizable to all European mountain grazing agroecosystems. The reliance on self-reported data from farmers through surveys could introduce potential biases. The Emergy Accounting approach, while comprehensive, relies on certain assumptions and data estimations, which can affect the accuracy of the results. The study's timeframe (30 years) might not capture all long-term impacts of agricultural policies.