Assessing the energy trap of industrial agriculture in North America and Europe: 82 balances from 1830 to 2012.

Early energy analyses of agriculture revealed that behind higher labor and land productivity of industrial farming, there was a decrease in energy returns on energy (EROI) invested, in comparison to more traditional organic agricultural systems. Studies on recent trends show that efficiency gains in production and use of inputs have again somewhat improved energy returns. However, most of these agricultural energy studies have focused only on external inputs at the crop level, concealing the important role of internal biomass flows that livestock and forestry recirculate within agroecosystems. Here, we synthesize the results of 82 farm systems in North America and Europe from 1830 to 2012 that for the first time show the changing energy profiles of agroecosystems, including livestock and forestry, with a multi-EROI approach that accounts for the energy returns on external inputs, on internal biomass reuses, and on all inputs invested. With this historical circular bioeconomic approach, we found a general trend towards much lower external returns, little or no increases in internal returns, and almost no improvement in total returns. This "energy trap" was driven by shifts towards a growing dependence of crop production on fossil-fueled external inputs, much more intensive livestock production based on feed grains, less forestry, and a structural disintegration of agroecosystem components by increasingly linear industrial farm managements. We conclude that overcoming the energy trap requires nature-based solutions to reduce current dependence on fossil-fueled external industrial inputs and increase the circularity and complexity of agroecosystems to provide healthier diets with less animal products. Supplementary Information: The online version contains supplementary material available at 10.1007/s13593-023-00925-5.

Assessing the sustainability of contrasting land use scenarios through the Socioecological Integrated Analysis (SIA) of the metropolitan green infrastructure in Barcelona.

Urban development and the sprawl of transport infrastructures have disregarded the crucial function of metropolitan landscape in provisioning human well-being and biodiversity. This research aims to contribute to the challenges of Planning for Sustainability by proposing a Socioecological Integrated Analysis (SIA) to support the Land Use Master Plan in the Barcelona Metropolitan Area, to conciliate urban development with the performance of surrounding open spaces. The paper evaluates four different land cover scenarios (current, trending, alternative and potential), and two kinds of agricultural management (conventional and a socioecological transition towards organic agriculture). The results suggest that although there are significant improvements on job provisioning and nutrient-cycling closures (circular economy), certified organic agriculture is not enough to overcome some trends of industrialized agrarian systems such as low energy efficiency or poor improvements in greenhouse gas emissions. The results also show a crossed effect between social metabolism and landscape ecology where changes in the management could affect the landscape functioning while changes in the land covers are particularly affecting the resource use. Then, deeper changes that consider together land use and metabolic flows are required to promote more sustainable agroecological transitions. The SIA model is an important conceptual and methodological step forward that facilitates the transition towards sustainable land use policies.

Agroecosystem energy transitions in the old and new worlds: trajectories and determinants at the regional scale.

Energy efficiency in biomass production is a major challenge for a future transition to sustainable food and energy provision. This study uses methodologically consistent data on agroecosystem energy flows and different metrics of energetic efficiency from seven regional case studies in North America (USA and Canada) and Europe (Spain and Austria) to investigate energy transitions in Western agroecosystems from the late nineteenth to the late twentieth centuries. We quantify indicators such as external final energy return on investment (EFEROI, i.e., final produce per unit of external energy input), internal final EROI (IFEROI, final produce per unit of biomass reused locally), and final EROI (FEROI, final produce per unit of total inputs consumed). The transition is characterized by increasing final produce accompanied by increasing external energy inputs and stable local biomass reused. External inputs did not replace internal biomass reinvestments, but added to them. The results were declining EFEROI, stable or increasing IFEROI, and diverging trends in FEROI. The factors shaping agroecosystem energy profiles changed in the course of the transition: Under advanced organic and frontier agriculture of the late nineteenth and early twentieth centuries, population density and biogeographic conditions explained both agroecosystem productivity and energy inputs. In industrialized agroecosystems, biogeographic conditions and specific socio-economic factors influenced trends towards increased agroecosystem specialization. The share of livestock products in a region's final produce was the most important factor determining energy returns on investment.

Displaying geographic variability of peri-urban agriculture environmental impacts in the Metropolitan Area of Barcelona: A regionalized life cycle assessment.

Peri urban agriculture (peri-UA) can supply food locally and potentially more sustainably than far-away conventional agricultural systems. It can also introduce significant environmental impacts depending on the local biophysical conditions and resources required to implement it and, on the crops managing practices, which could vary widely among growers. Sophisticated methods to account for such variability while assessing direct (on-site) and indirect (up/down stream) environmental impacts of peri-UA implementation are thus needed. We implemented an attributional, regionalized, cradle-to-gate life cycle assessment (LCA) for which we derive spatially explicit inventories and calculate 14 impacts due to peri-UA using the ReCiPe method. Further, to show the importance of impact assessment regionalization for the environmental assessment of peri-UA, we regionalize eutrophication impacts characterization. We use the Metropolitan Area of Barcelona (AMB) to illustrate these methodological developments. Vegetables and greenhouses, the prevalent peri-UA land uses, had the largest impacts assessed, of all peri-UA land uses. European NPK mineral fertilizer production to cover N demand of these crops drives all impacts. For fruit crops, on-site N emissions drive marine eutrophication impacts and for irrigated herbaceous crops, phosphate runoff drives freshwater eutrophication impacts. Geographic variability of peri-UA metabolic flows and impacts was displayed. Management practices at the plots, which are linked the land use, are responsible for impacts variability. Regionalization of eutrophication impacts highlights the importance of accounting for the biophysical aspects at the geographic scale at which peri-UA takes place, which is a much finer scale than those implemented in current regionalization of impact assessment methods in LCA. This study provides a fundamental baseline needed to assess transition scenarios of peri-UA at an appropriate geographic level of analysis and gives essential knowledge to guide appropriate circular and sustainability strategies for the sector.

An energy-landscape integrated analysis to evaluate agroecological scarcity.

Agrarian landscapes theoretically provide ecosystem services that meet the demands of a wide range of socioecological processes. Consequently, any landscape agroecology approach must tackle the dynamic interaction of land-use distribution and associated social metabolism at different spatiotemporal scales. An agroecological scarcity case study explores how driven agricultural energy flows interact with landscape complexity in arid landscapes of 46 counties in the Qazvin Province (Iran). An Energy-Landscape Integrated Analysis (ELIA) was performed to correlate the energy reinvestment (E) and energy redistribution (I) present within the social metabolism network, with landscape complexity (Le) measured in terms of spatial patterns and related ecological processes. As well, a cluster analysis was run to establish agrarian landscape typologies based on the ELIA indicators. The results of this study provide an explicit sketch of the four strategies that society in Qazvin Province has developed within the dry environments that sustain it. Our findings confirm the hypothesis that there is a positive relationship between optimizing non-dissipative internal energy loops and landscape complexity, which can explain agroecosystem sustainability. This research enables us to define spatially informed agroecological transitions from a territorially explicit socioecological perspective and will make a significant contribution to decisions on agricultural policies given different land-use strategies, especially under scenarios of ecological scarcity.