Abstract
Animal husbandry, aquaculture and fishery have major impacts on the environment. In order to identify the range of impacts and the most important factors thereof, as well as to identify what are the main causes of the differences between products, we analysed 52 life cycle assessment studies (LCAs) of animal and vegetal sources of protein. Our analysis was focused only on land requirement and carbon footprints. In a general conclusion it can be said that the carbon footprint of the most climate-friendly protein sources is up to 100 times smaller than those of the most climate-unfriendly. The differences between footprints of the various products were found mainly to be due to differences in production systems. The outcomes for pork and poultry show much more homogeneity than for beef and seafood. This is largely because both beef and seafood production show a wide variety of production systems. Land use (occupation), comprising both arable land and grasslands, also varies strongly, ranging from negligible for seafood to up to 2100 m² y kg−1 of protein from extensive cattle farming. From farm to fork the feed production and animal husbandry are by far the most important contributors to the environmental impacts.
Generated Summary
This research, published in Food Policy, investigates the environmental impact of animal food products and their substitutes, specifically focusing on land use and carbon footprints. The study utilizes a life cycle assessment (LCA) approach, analyzing 52 different LCAs of both animal and plant-based protein sources to identify the main factors contributing to environmental impacts. The core methodology involves comparing and contrasting the carbon footprints and land requirements associated with various protein sources. The scope of the analysis is limited to evaluating the environmental consequences related to the production of these different protein sources, from their origin to the consumer. The study seeks to determine the differences in environmental impacts between products, with a particular emphasis on land requirements and carbon footprints associated with each.
Key Findings & Statistics
- The study examined 52 life cycle assessment studies (LCAs) of animal and vegetal sources of protein.
- The carbon footprint of the most climate-friendly protein sources can be up to 100 times smaller than those of the least climate-friendly sources.
- Land use (occupation) varies strongly, ranging from negligible for seafood to up to 2100 m² y kg⁻¹ of protein from extensive cattle farming.
- 104 Carbon footprints of protein sources are examined.
- 43 Land footprints of protein sources are examined.
- From farm to fork, feed production and animal husbandry are by far the most important contributors to environmental impacts.
Other Important Findings
- Large differences in impact between protein sources were found.
- In the life cycles, in general, the farm phase is the most important.
- Vegetal sources, poultry products, and certain seafood have low carbon footprints.
- Ruminant meat and some types of seafood have high carbon footprints.
Limitations Noted in the Document
- The study focuses primarily on land use and carbon footprints, potentially overlooking other environmental impacts such as water usage, biodiversity loss, and eutrophication.
- The analysis relies on existing LCA studies, which may have varying methodologies, data quality, and scope, leading to potential inconsistencies and limitations in the comparability of results.
- The study doesn’t provide details on the specific production systems and practices that lead to lower carbon footprints or land use, which may limit practical applications of the findings.
- The scope of the study is limited to animal and vegetal sources of protein, potentially neglecting other dietary components and their respective environmental impacts.
Conclusion
This research underscores the significant environmental variability among different protein sources, particularly in terms of their carbon footprints and land use requirements. The study highlights that the carbon footprint of certain protein sources is dramatically smaller than others, with the most climate-friendly sources showing up to 100 times less impact compared to the least environmentally friendly. This disparity primarily results from differences in production systems, such as the distinction between intensive farming methods and extensive cattle grazing. The findings also underscore the importance of the farm phase in the life cycle, as well as the substantial contribution of feed production and animal husbandry to overall environmental impacts. In order to decrease the impacts of food production, this evidence indicates that diets based on vegetables and poultry products may be a superior alternative compared to animal products that carry a greater carbon footprint, such as ruminant meat, and some seafood. Overall, the review suggests that shifting dietary patterns towards more sustainable protein sources can substantially decrease environmental impact.