The environmental impact of milk and plant-based alternatives has been widely discussed over the past decade. However, it was not until recently that this comparison began to rely on harmonised, global and comparable data. Since then, scientific evidence has evolved, providing a much clearer picture of where the main environmental impacts lie and where meaningful opportunities for improvement exist.
This article reviews the scientific evidence behind the environmental footprint of different types of milk, from the study that marked a turning point in the global debate to the most recent research, and connects these findings with the sustainability approach of the DELICIOUS project.
Poore & Nemecek and the context of milk comparisons
In 2018, the study led by Joseph Poore and Thomas Nemecek marked a turning point in how the environmental impact of food is assessed. For the first time, thousands of real production systems were analysed using a harmonised life cycle assessment approach, allowing very different products to be compared under the same methodological framework.
Milk became a particularly relevant case study within this global analysis. Its importance in diets, its economic relevance and the growing availability of plant-based alternatives made it an ideal example to explore how different production systems perform in terms of emissions, land use and pressure on natural resources.
Rather than ranking products as “good” or “bad”, this comparison aimed to identify structural patterns and to better understand the environmental efficiency of different food systems.
What the results show: clear differences between milk types
The global life cycle assessment published in 2018 by Joseph Poore and Thomas Nemecek provides one of the most robust and comprehensive comparisons of the environmental footprint of different types of milk. Beyond headline figures, the study offers a system-level understanding of where impacts come from and why they differ so strongly across production models.
Greenhouse gas emissions
In terms of climate impact, the study shows clear and consistent differences between animal and plant-based milk.
Cow’s milk has an average footprint of around 3 kg CO₂ equivalent per litre, while sheep milk reaches close to 4 kg CO₂e per litre and goat milk slightly above 3 kg CO₂e per litre. These higher values are mainly driven by methane emissions from ruminants and by emissions associated with feed production.
By contrast, most plant-based drinks fall below 1–1.2 kg CO₂ equivalent per litre. Soy and oat drinks are among the lowest-impact options, while rice-based drinks show somewhat higher values, reflecting differences in crop production systems.
Overall, the study shows that animal milk generates around three times more climate impact per litre than most plant-based alternatives.
Land use
Land use is one of the indicators where differences between milk types are most pronounced.
Producing animal milk requires several times more land per litre than producing plant-based drinks. This is largely due to the need to grow feed crops and the inherent inefficiency of converting plant calories into animal-based products.
Plant-based drinks bypass this conversion step, resulting in a much lower land footprint. This has direct implications for deforestation pressure, biodiversity loss and competition for agricultural land.
Water use
Water use shows strong variability across milk types and highlights the importance of context.
Animal milk has a high overall water footprint when the full production chain is considered, mainly driven by irrigated feed crops and the complexity of livestock systems.
Among plant-based drinks, water use depends strongly on the crop and the region of production. Soy and oat drinks tend to show relatively low water use per litre, while almond and rice drinks can require large volumes of water, particularly when cultivated in water-stressed regions.
This finding underlines a key message from the study: plant-based does not automatically mean low-water, and geographical context plays a critical role.
Eutrophication and nutrient pollution
The study also highlights eutrophication as a major environmental pressure associated with milk production. This indicator reflects the impact of excess nutrients, mainly nitrogen and phosphorus, entering aquatic ecosystems.
Animal milk shows a clearly higher eutrophication impact than plant-based drinks. The main drivers are fertiliser use for feed production and manure management in livestock systems, which lead to nutrient losses to water bodies.
Plant-based drinks generally show much lower eutrophication impacts, although agricultural practices remain an important factor.
Variability and system-level insights
One of the most important contributions of the 2018 study goes beyond average values. It shows that environmental impacts vary widely between producers, even within the same product category.
This leads to a critical insight: improving production practices, particularly among the worst-performing producers, can deliver significant environmental gains. In other words, how milk is produced matters as much as what type of milk is produced.
At the same time, the study makes clear that plant-based alternatives are not impact-free. Their performance depends on crop choice, yields, location and farming practices, reinforcing the need for informed, system-level decision-making.
Taken together, these results demonstrate that differences between milk types are not marginal. They reflect fundamental structural differences in production systems, providing a solid evidence base for understanding environmental trade-offs and identifying where innovation can deliver the greatest impact.
What recent studies confirm
Since the publication of the 2018 study, a key question has been whether these conclusions still hold true.
Scientific reviews published in 2024, bringing together and analysing dozens of independent life cycle assessment studies, confirm that the general patterns identified in 2018 remain valid across different regions and production systems.
These reviews consistently show that:
Animal milk maintains higher impacts in terms of emissions, land use, water-related pressures and eutrophication
Most plant-based drinks have lower environmental footprints
Differences between plant-based alternatives are significant and should be assessed case by case
Rather than overturning earlier findings, recent studies consolidate and refine them, reinforcing the need to avoid overly simplistic conclusions.
Sustainability in DELICIOUS: redesigning ingredients to reduce impacts
Within this context of consolidated scientific evidence, the DELICIOUS project addresses sustainability through innovation and ingredient redesign.
One of the environmental challenges associated with many plant-based dairy alternatives is the use of coconut and palm fats. These fats are widely used for their functional properties, but they are associated with relevant environmental impacts, particularly related to land use, biodiversity loss and long supply chains.
DELICIOUS works to reduce and replace these fats by developing novel fermentation-based ingredients that can deliver functionality, texture and sensory performance without relying on raw materials with higher environmental footprints.
This approach makes it possible to:
Reduce dependency on tropical fats
Lower pressure on land use and sensitive ecosystems
Improve the overall environmental profile of dairy alternatives
Maintain product quality, functionality and consumer acceptance
Sustainability in DELICIOUS is therefore addressed across the entire value chain, combining process efficiency, ingredient selection and product design aligned with market needs.
Sources
Poore, J. & Nemecek, T. (2018). Reducing food’s environmental impacts through producers and consumers. Science.
Systematic review on the environmental impact of animal and plant-based milk (2024). Journal of Cleaner Production.
