Organic farming practices have been promoted as, inter alia, reducing the environmental impacts of agriculture. This meta-analysis systematically analyses published studies that compare environmental impacts of organic and conventional farming in Europe. The results show that organic farming practices generally have positive impacts on the environment per unit of area, but not necessarily per product unit. Organic farms tend to have higher soil organic matter content and lower nutrient losses (nitrogen leaching, nitrous oxide emissions and ammonia emissions) per unit of field area. However, ammonia emissions, nitrogen leaching and nitrous oxide emissions per product unit were higher from organic systems. Organic systems had lower energy requirements, but higher land use, eutrophication potential and acidification potential per product unit. The variation within the results across different studies was wide due to differences in the systems compared and research methods used. The only impacts that were found to differ significantly between the systems were soil organic matter content, nitrogen leaching, nitrous oxide emissions per unit of field area, energy use and land use. Most of the studies that compared biodiversity in organic and conventional farming demonstrated lower environmental impacts from organic farming. The key challenges in conventional farming are to improve soil quality (by versatile crop rotations and additions of organic material), recycle nutrients and enhance and protect biodiversity. In organic farming, the main challenges are to improve the nutrient management and increase yields. In order to reduce the environmental impacts of farming in Europe, research efforts and policies should be targeted to developing farming systems that produce high yields with low negative environmental impacts drawing on techniques from both organic and conventional systems.

Normalization and weighting steps used in life cycle impact assessment (LCIA) are often ignored as the weighting factors currently available are seen as being uncertain, subjective and unreliable. This article aims to contribute to the development of a new approach towards weighting, exploring the application of the concept of a planetary safe operating space for human welfare. Based on this approach, the boundaries included in this study relate to: climate change, rate of biodiversity loss, nitrogen cycle, phosphorus cycle, stratospheric ozone depletion, global freshwater use and change in land use. The weighting factors are then applied to a case study comparing environmental impacts of organic, conventional and integrated farming systems with alternative land uses. An integrated farming system that uses a part of the land for natural forest was found to have the lowest total impact score. Conventional farming systems with Miscanthus and managed forest had the highest total impact scores. The main source of uncertainty in the results arose from the wide range of assessments for the safe boundary of the biodiversity loss impact category. As the weighting factors proposed in this paper are not based on the common LCA impact categories, more work is needed to adjust the weighting factors to be suitable for use in LCA studies. More research is also needed for further defining the safe planetary boundaries.

Life cycle assessment (LCA) is commonly used for comparing environmental impacts of contrasting farming systems. However, the interpretation of agricultural LCA studies may be flawed when the alternative land use options are not properly taken into account. This study compared energy and greenhouse gas (GHG) balances and biodiversity impacts of different farming systems by using LCA accompanied by an assessment of alternative land uses. Farm area and food product output were set equal across all of the farm models, and any land remaining available after the food crop production requirement had been met was assumed to be used for other purposes. Three different management options for that land area were compared: Miscanthus energy crop production, managed forest and natural forest. The results illustrate the significance of taking into account the alternative land use options and suggest that integrated farming systems have potential to improve the energy and GHG balances and biodiversity compared to both organic and conventional systems. Sensitivity analysis shows that the models are most sensitive for crop and biogas yields and for the nitrous oxide emission factors. This paper provides an approach that can be further developed for identifying land management systems that optimize food production and environmental benefits.

To ensure a sustainable food supply for the growing population, the challenge is to find agricultural systems that can meet production requirements within environmental constraints and demands. This study compares the impacts of winter wheat production on energy use, land use and 100 years Global Warming Potential (GWP100) under different arable farming systems and farming practices. Life cycle assessment was used to simulate the impacts of organic, conventional and integrated farming (IF) systems along the production chain from input production up to the farm gate. The IF system models were designed to combine the best practices from organic and conventional systems to reduce negative environmental impacts without significant yield reductions. An integrated system that used food waste digestate as a fertiliser, and utilised pesticides and no-tillage had the lowest energy use and GWP per functional unit of 1000 kg wheat output. When the impacts of some specific practices for reducing energy use and GWP were compared, the highest energy use reductions were achieved by replacing synthetic nitrogen fertilisers with anaerobically treated food waste or nitrogen fixing crops, increasing yields through crop breeding and using no-tillage instead of ploughing. The highest GWP reductions were achieved by using nitrification inhibitors, replacing synthetic nitrogen fertilisers and increasing yields. The major contributors to the uncertainty range of energy use were associated with machinery fuel use and the assumed crop yields. For GWP results, the main source of uncertainty related to the N2O emissions. In conclusion, farming systems that combine the best practices from organic and conventional systems have potential to reduce negative environmental impacts while maintaining yield levels.

Cultured meat (i.e., meat produced in vitro using tissue engineering techniques) is being developed as a potentially healthier and more efficient alternative to conventional meat. Life cycle assessment (LCA) research method was used for assessing environmental impacts of large-scale cultured meat production. Cyanobacteria hydrolysate was assumed to be used as the nutrient and energy source for muscle cell growth. The results showed that production of 1000 kg cultured meat requires 26–33 GJ energy, 367–521 m3 water, 190–230 m2 land, and emits 1900–2240 kg CO2-eq GHG emissions. In comparison to conventionally produced European meat, cultured meat involves approximately 7–45% lower energy use (only poultry has lower energy use), 78–96% lower GHG emissions, 99% lower land use, and 82–96% lower water use depending on the product compared. Despite high uncertainty, it is concluded that the overall environmental impacts of cultured meat production are substantially lower than those of conventionally produced meat.

Feeding the world’s growing human population with increased consumption of livestock products would require huge expansion in agricultural production by 2050. This study compared environmental impacts of producing different protein sources for human nutrition, including crops, livestock products, Spirulina, mycoprotein based QuornTM and cultured meat. The results showed that Spirulina and cultured meat have the lowest land use per unit of protein and unit of human digestible energy.
Crops have the lowest energy use and greenhouse gas (GHG) emissions per unit of energy and protein. The energy use in cultured meat production is at the same level with other livestock products, whereas GHG emissions are lower. It is concluded that the overall impacts of replacing livestock products with crops, Spirulina, Quorn and cultured meat would be beneficial for the environment and would potentially improve
food security as less land is needed for producing the same amount of protein and energy.

Cultured meat is produced in vitro by using tissue engineering techniques. It is being developed as a potentially healthier and more efficient alternative to conventional meat. The goal of this study was to estimate energy use, land requirements, and greenhouse gas (GHG) emissions for large-scale cultured meat production. Life cycle assessment (LCA) research method was used for assessing the environmental impacts along the production chain. Cyanobacteria hydrolysate was assumed to be used as the nutrient and energy source for muscle cell growth. The results showed that cultured meat production involves approximately 35-60% lower energy use, 80-95% lower GHG emissions and 98% lower land use compared to conventionally produced meat products in Europe. Conventionally produced poultry had slightly lower energy use than cultured meat. It is concluded that the overall environmental impacts of cultured meat production are substantially lower than those of conventionally produced meat.

Keywords: in vitro meat, environmental impacts, energy use, greenhouse gas emissions, land use

Biofuels have been promoted as a way to reduce greenhouse gas (GHG) emissions, but it is questionable whether they indeed do so. The study compared energy and GHG balances of transport biofuels produced in Finnish conditions. Energy and GHG balances were calculated from a life cycle perspective for biogas when timothy-clover and reed canary grass silages and green manure of an organic farm were used as a raw material. The results were compared with published data on barley-based ethanol, rape methyl ester (biodiesel) and biowaste-based biogas. The energy input for biogas was 22-37% of the output depending on the raw material. The GHG emissions from field-based biogas were 21-36% of emissions from fossil-based fuels. The largest energy input was used in the processing of the biofuels while most of the greenhouse gases were emitted during farming. The GHG emissions of the field-based biogas were emitted mainly from fuels of farming machinery, nitrous oxide (N2O) emissions of the soil and the production of ensiling additives. The energy efficiency was most sensitive to the methane yield, and GHG emissions to the N2O emissions. Biogas had clearly lower energy input and GHG emissions per unit energy output than domestic barley-based ethanol and biodiesel.

The paper presents how opportunity costs of land use can be taken into account when life cycle assessment (LCA) is used to compare environmental impacts of contrasting farming systems. Energy and greenhouse gas (GHG) balances of organic, conventional and integrated farm models are assessed. It is assumed that the farm size and food product output are equivalent in all farm models, and the remaining land that is not needed for food crops is used for Miscanthus energy crop production. The impacts of integrating biogas production into the farming systems are also explored. The results illustrate the significance of taking into account the opportunity costs of land use and suggest that integrating farming systems can have potential to reduce the negative environmental impacts compared to organic and conventional systems.

Key words: organic farming, integrated farming, greenhouse gas emissions, land use, energy balance, bioenergy, biogas