Christian Schader

Environmental impacts of organic and conventional agricultural products – Are the differences captured by life cycle assessment?

Comprehensive assessment tools are needed that reliably describe environmental impacts of different agricultural systems in order to develop sustainable high yielding agricultural production systems with minimal impacts on the environment. Today, Life Cycle Assessment (LCA) is increasingly used to assess and compare the environmental sustainability of agricultural products from conventional and organic agriculture. However, LCA studies comparing agricultural products from conventional and organic farming systems report a wide variation in the resource efficiency of products from these systems. The studies show that impacts per area farmed land are usually less in organic systems, but related to the quantity produced impacts are often higher. We reviewed 34 comparative LCA studies of organic and conventional agricultural products to analyze whether this result is solely due to the usually lower yields in organic systems or also due to inaccurate modeling within LCA. Comparative LCAs on agricultural products from organic and conventional farming systems often do not adequately differentiate the specific characteristics of the respective farming system in the goal and scope definition and in the inventory analysis. Further, often only a limited number of impact categories are assessed within the impact assessment not allowing for a comprehensive environmental assessment. The most critical points we identified relate to the nitrogen (N) fluxes influencing acidification, eutrophication, and global warming potential, and biodiversity. Usually, N-emissions in LCA inventories of agricultural products are based on model calculations. Modeled N-emissions often do not correspond with the actual amount of N left in the system that may result in potential emissions. Reasons for this may be that N-models are not well adapted to the mode of action of organic fertilizers and that N-emission models often are built on assumptions from conventional agriculture leading to even greater deviances for organic systems between the amount of N calculated by emission models and the actual amount of N available for emissions. Improvements are needed regarding a more precise differentiation between farming systems and regarding the development of N emission models that better represent actual N-fluxes within different systems. We recommend adjusting N- and C-emissions during farmyard manure management and farmyard manure fertilization in plant production to the feed ration provided in the animal production of the respective farming system leading to different N- and C-compositions within the excrement. In the future, more representative background data on organic farming systems (e.g. N content of farmyard manure) should be generated and compiled so as to be available for use within LCA inventories. Finally, we recommend conducting consequential LCA - if possible - when using LCA for policy-making or strategic environmental planning to account for different functions of the analyzed farming systems.

Impacts of feeding less food-competing feedstuffs to livestock on global food system sustainability.

Increasing efficiency in livestock production and reducing the share of animal products in human consumption are two strategies to curb the adverse environmental impacts of the livestock sector. Here, we explore the room for sustainable livestock production by modelling the impacts and constraints of a third strategy in which livestock feed components that compete with direct human food crop production are reduced. Thus, in the outmost scenario, animals are fed only from grassland and by-products from food production. We show that this strategy could provide sufficient food (equal amounts of human-digestible energy and a similar protein/calorie ratio as in the reference scenario for 2050) and reduce environmental impacts compared with the reference scenario (in the most extreme case of zero human-edible concentrate feed: greenhouse gas emissions −18%; arable land occupation −26%, N-surplus −46%; P-surplus −40%; non-renewable energy use −36%, pesticide use intensity −22%, freshwater use −21%, soil erosion potential −12%). These results occur despite the fact that environmental efficiency of livestock production is reduced compared with the reference scenario, which is the consequence of the grassland-based feed for ruminants and the less optimal feeding rations based on by-products for non-ruminants. This apparent contradiction results from considerable reductions of animal products in human diets (protein intake per capita from livestock products reduced by 71%). We show that such a strategy focusing on feed components which do not compete with direct human food consumption offers a viable complement to strategies focusing on increased efficiency in production or reduced shares of animal products in consumption.

Strategies for feeding the world more sustainably with organic agriculture

Organic agriculture is proposed as a promising approach to achieving sustainable food systems, but its feasibility is also contested. We use a food systems model that addresses agronomic characteristics of organic agriculture to analyze the role that organic agriculture could play in sustainable food systems. Here we show that a 100% conversion to organic agriculture needs more land than conventional agriculture but reduces N-surplus and pesticide use. However, in combination with reductions of food wastage and food-competing feed from arable land, with correspondingly reduced production and consumption of animal products, land use under organic agriculture remains below the reference scenario. Other indicators such as greenhouse gas emissions also improve, but adequate nitrogen supply is challenging. Besides focusing on production, sustainable food systems need to address waste, crop–grass–livestock interdependencies and human consumption. None of the corresponding strategies needs full implementation and their combined partial implementation delivers a more sustainable food future.Organic agriculture requires fewer inputs but produces lower yields than conventional farming. Here, via a modeling approach, Muller et al. predict that if food waste and meat consumption are reduced, organic agriculture could feed the world without requiring cropland expansion.

When experts disagree: the need to rethink indicator selection for assessing sustainability of agriculture

Sustainability indicators are well recognized for their potential to assess and monitor sustainable development of agricultural systems. A large number of indicators are proposed in various sustainability assessment frameworks, which raises concerns regarding the validity of approaches, usefulness and trust in such frameworks. Selecting indicators requires transparent and well-defined procedures to ensure the relevance and validity of sustainability assessments. The objective of this study, therefore, was to determine whether experts agree on which criteria are most important in the selection of indicators and indicator sets for robust sustainability assessments. Two groups of experts (Temperate Agriculture Research Network and New Zealand Sustainability Dashboard) were asked to rank the relative importance of eleven criteria for selecting individual indicators and of nine criteria for balancing a collective set of indicators. Both ranking surveys reveal a startling lack of consensus amongst experts about how best to measure agricultural sustainability and call for a radical rethink about how complementary approaches to sustainability assessments are used alongside each other to ensure a plurality of views and maximum collaboration and trust amongst stakeholders. To improve the transparency, relevance and robustness of sustainable assessments, the context of the sustainability assessment, including prioritizations of selection criteria for indicator selection, must be accounted for. A collaborative design process will enhance the acceptance of diverse values and prioritizations embedded in sustainability assessments. The process by which indicators and sustainability frameworks are established may be a much more important determinant of their success than the final shape of the assessment tools. Such an emphasis on process would make assessments more transparent, transformative and enduring.

How the organic food system supports sustainable diets and translates these into practice

Organic production and consumption provide a delineated food system that can be explored for its potential contribution to sustainable diets. While organic agriculture improves the sustainability performance on the production side, critical reflections are made on how organic consumption patterns, understood as the practice of people consuming significant amounts of organic produce, may also be taken as an example for sustainable food consumption. The consumption patterns of regular organic consumers seem to be close to the sustainable diet concept of FAO. Certain organic-related measures might therefore be useful in the sustainability assessment of diets, e.g., organic production and organic consumption. Since diets play a central role in shaping food systems and food systems shape diets, the role of organic consumption emerges as an essential topic to be addressed. This role may be based on four important organic achievements: organic agriculture and food production has a definition, well-established principles, public standards, and useful metrics. By 2015, data for organic production and consumption are recorded annually from more than 160 countries, and regulations are in force in more than 80 countries or regions. The organic food system puts the land (agri-cultura) back into the diet; it is the land from which the diet in toto is shaped. Therefore, the organic food system provides essential components of a sustainable diet.

Environmental performance of organic farming

As a typical cradle-to-cradle approach, organic farming suits the notion of a green technology. However, a generally valid quantification of the environmental performance of organic agriculture is difficult because there is a high variability between countries, regions, farm types, and products. Furthermore, different assessment methods lead to partly contradicting conclusions on the environmental impacts of organic farming. This chapter gives an overview on the environmental impacts of organic agriculture compared with those of conventional agriculture based on state-of-the-art literature and discusses methodological implications for the comparison of environmental impacts of farming systems. According to most of the reviewed literature organic farming performs better in terms of biodiversity, soil fertility and air quality, mitigating resource depletion, climate change mitigation, and groundwater pollution as compared with conventional agriculture. However, there are single environmental indicators in some of the above-mentioned fields, against which organic agriculture performs equally or even worse (N2O emissions and CH4 emissions per unit of product produced), depending on the assumptions and methodology of the study. Finally, this paper highlights nine common methodological problems of quantifying environmental impacts of farming systems that have been identified in the reviewed literature and suggests solutions for improvement.

The role of multi-target policy instruments in agri-environmental policy mixes

The Tinbergen Rule has been used to criticise multi-target policy instruments for being inefficient. The aim of this paper is to clarify the role of multi-target policy instruments using the case of agri-environmental policy. Employing an analytical linear optimisation model, this paper demonstrates that there is no general contradiction between multi-target policy instruments and the Tinbergen Rule, if multi-target policy instruments are embedded in a policy-mix with a sufficient number of targeted instruments. We show that the relation between cost-effectiveness of the instruments, related to all policy targets, is the key determinant for an economically sound choice of policy instruments. If economies of scope with respect to achieving policy targets are realised, a higher cost-effectiveness of multi-target policy instruments can be achieved. Using the example of organic farming support policy, we discuss several reasons why economies of scope could be realised by multi-target agri-environmental policy instruments.

Farm- and product-level biodiversity assessment of conventional and organic dairy production in Austria

The novel method developed for this study evaluates the impact of farming practices on farmland biodiversity, allowing for the assessment of the biodiversity potential of dairy farms at farm and product levels. We linked farming practices as pressure indicators to the species number and abundance of 11 indicator species groups (ISGs), evaluated semi-quantitatively by expert judgements. We calculated biodiversity potential based on food–web relationships between the ISGs, using Monte Carlo simulations for the analysis of uncertainty of expert assessments. We applied the assessment model to 8925 dairy farms from seven different Austrian regions, using official statistical data sets at farm level and interviews with farmers and experts. The results show that the approach can be used to identify differences in the biodiversity potential of farms and milk. Milk from organic farms received 4–79% higher biodiversity scores than milk from conventional farms in all regions. The application showed that in the case of Austrian dairy production, the approach can be used for assessments of both farms and products. However, the approach needs validation and, for product-level assessment, further development to cope with longer supply chains or compound products from different bio-geographic regions.

Societal Demand for Commodity and Non-commodity Outputs – A Regional Perspective

Societal demand for the multifunctionality of agriculture was analysed in four case-study regions by studying stakeholders’ perceptions of regional priorities. We used the Stakeholder Delphi Approach, which is a qualitative, two-step procedure, based on revealed preferences of a principal consisting of stakeholders and experts from the regions. The results of our case studies imply that demand for functions of agriculture is generally strong. Comparing the priorities among the case studies, we found different demand patterns in each region. Further discussion of the Wielkopolska case study, with a production-focussed demand pattern, and the River Gudena case study, with a post-productivist pattern, illustrates the regional characteristics that have shaped the distinct demand pattern in these regions.