An increased dependence on agricultural policies led European grazing agroecosystems to an unsustainability trap

The paper addresses how sustainability in European mountain grazing agroecosystems has evolved amid rising global dependence of the agrifood system on non-renewable energy and materials. While grazing systems are often promoted for using local renewable resources, European grazing farms have become economically unprofitable within globalized markets and increasingly dependent on Common Agricultural Policy (CAP) payments. The study aims to quantify, from a systems ecology and thermodynamic perspective using Emergy Accounting, the evolution (1990–2018) of environmental sustainability in Spanish Pyrenees grazing farms, evaluate whether different regional farming trajectories lead to distinct sustainability outcomes, and discuss CAP’s role. The central hypothesis is that despite local shifts toward longer grazing and reduced external feeds, increased reliance on socio-economic flows (notably CAP and services largely backed by non-renewable sources) has driven an overall decline in sustainability.

Prior research documents increasing energy efficiency in agriculture accompanied by greater absolute use of fossil fuels and transgression of planetary boundaries. National and regional emergy-based assessments typically find improved efficiency but growing non-renewable dependence, leading to stagnation or decline in sustainability. Grazing systems are posited as alternatives leveraging non-arable lands, local renewables, rural employment, and reduced purchased inputs and environmental burdens when properly managed. However, European grazing farms face competitive disadvantages versus industrial systems, becoming reliant on CAP’s direct payments and rural development funds to maintain profitability. While such socio-economic dependencies are covered in socio-economic analyses, their environmental implications are underexplored; integrating policy-related monetary inflows in environmental accounting (emergy) is necessary to understand real sustainability dynamics.

Study area and sample: 50 cattle farms in three valleys of the Spanish central Pyrenees (Broto, Benasque, Baliera-Barrabés) were monitored via in-depth face-to-face surveys at three time points: 1990, 2004, and 2018, following ethics approval. The valleys represent diverse farming systems and biophysical/socio-economic contexts.

Emergy Accounting: The system boundaries included local renewable inputs (R: sun, deep heat, rain, wind; topsoil/organic matter; natural pastures), local non-renewables (N), purchased inputs (F: animal feeds, crop inputs, machinery/buildings, energy, veterinary/medicines), services and labour (S), subsidies and taxes (monetary flows, including CAP), and product outputs (milk, weaned/fattened calves). All inputs and outputs were converted to emergy (sej) using appropriate transformities/UEVs; total emergy yield (U) sums all supporting inflows. The Global Emergy Baseline adopted was 12.0E+24 sej/yr.

Indicators: Calculated emergy-based indicators include Transformity/UEV, Renewability (%R = R/U), Emergy Yield Ratio (EYR = U/(F+S)), Emergy Investment Ratio (EIR = (F+S)/(R+N)), Emergy Exchange Ratio (EER = U/M), Environmental Loading Ratio (ELR = (N+F+S)/R), Emergy Sustainability Index (ESI = EYR/ELR), and Source Diversity Index (SDI; normalized as SDI/SDImax) to evaluate input-source diversity and resilience.

Analyses: Time evolution (1990, 2004, 2018) was assessed across all farms and within four identified trajectories (one per valley plus a common across-valleys group) using ANOVA or Kruskal–Wallis depending on data characteristics. Statistical analyses and graphics were produced in R (v4.2.2).

• Input composition shifts: From 1990 to 2004 the emergy share from animal feeds, crop inputs, and labour roughly halved, coinciding with a regional shift from dairy to beef; from 2004 to 2018 these shares changed little. Conversely, the relative contribution of CAP payments, services, and other purchased items multiplied between 1990 and 2004 and then stabilized. The relative contribution of local natural resources declined over time, with natural pastures’ contribution stagnating.
• Emergy indicators (1990→2004 main changes, then relative stability): • Renewability (%R) decreased, indicating less reliance on renewable inputs in total emergy support. • EYR (contribution to socio-economic system) decreased; farms’ net contribution diminished. • EIR (market dependency) increased; greater dependence on market-provided resources and services. • ELR (environmental load) increased; higher load relative to local renewable inputs. • ESI (sustainability) approximately halved from 1990 to 2004, remaining in non-sustainable ranges across the 30-year period. • EER (market trade status) indicated uneven exchange; increased CAP inflows in later periods moved farms closer to fair trade (EER ≈ 1). • Variability across farms decreased for most indicators.
• Convergence across trajectories: Despite distinct structural/technical/socio-economic trajectories in the three valleys and a cross-valley group, all followed similar sustainability trends and remained within comparable indicator thresholds, with only minor differences.
• Resilience and input diversity: SDI/SDImax significantly declined over 30 years (p < 0.01), especially from 1990 to 2004, reflecting reduced diversity of input sources due to increased dependence on a few resource-intensive flows (services, CAP) and simplified feeding after the dairy-to-beef transition. Broto trajectory generally showed higher SDI values at each time point.
• Policy/economic context: CAP represented on average about 70% of farm gross margin in 2004 and 2018, highlighting strong policy dependence. Given Spain’s socio-economic system being 86–95% supported by non-renewable emergy (2001–2015), increased monetary and service inflows effectively import non-renewable dependence into farms, offsetting local gains from longer grazing and reduced purchased feeds.

The results demonstrate a decoupling between local management improvements and global sustainability outcomes. Locally, farms extended grazing seasons, expanded agricultural areas, and reduced purchased feeds and crop inputs—actions that should increase direct use of renewables and reduce non-renewables. However, these gains were outweighed by increased indirect dependence on socio-economic flows (CAP and services) predominantly supported by non-renewable energy at the national/global level. Consequently, emergy indicators show declining renewability, rising market dependence and environmental load, reduced net contribution to the economy, and an overall decline in sustainability (ESI), while input-source diversity fell, potentially undermining resilience. The hierarchical nature of coupled human–natural systems constrains farms (lower level) by broader socio-economic structures (higher level), limiting the extent to which farm-level practices alone can deliver environmental sustainability. Nonetheless, grazing systems still use relatively fewer non-renewables than more intensive livestock systems and can contribute to food security and rural livelihoods, but their sustainability remains contingent on wider society’s energy base and policy design.

Integrating biophysical and monetary flows through Emergy Accounting reveals that European mountain grazing agroecosystems transitioned toward locally more sustainable practices (longer grazing, reduced external feeds) yet fell into an unsustainability trap driven by rising dependence on CAP payments and services with high non-renewable backing. Across diverse regional trajectories, sustainability indicators deteriorated mainly between 1990 and 2004 and stabilized thereafter at non-sustainable levels, while input-source diversity declined. Policy implications are clear: to enable genuinely sustainable grazing systems, reforms must reduce the fossil-based underpinnings of socio-economic support and align CAP and related services with renewable-based pathways. Future research should co-design policy scenarios that internalize emergy-informed metrics, assess transitions to lower fossil-energy dependence, and explore strategies that enhance input-source diversity and resilience at farm and regional scales.