A new analysis of milk options suggests oat and soy are the most sustainable plant-based alternatives to dairy, with almond milk lagging due to high water use. The study, based on Australian data, compares environmental impacts including greenhouse gas emissions, water consumption, and processing.
According to the World Resources Institute, average emissions per cup are 330g for dairy, 122g for soy, 102g for oat, and 98g for almond. Dr Michalis Hadjikakou of Deakin University notes that all plant-based milks have lower emissions than dairy, largely because cows produce methane through digestion.
Water use varies significantly. Oat milk is the best option, as oats are typically rain-fed. Dairy and soy have moderate water footprints depending on irrigation practices. Almond milk, however, requires substantial irrigation, making it the least water-efficient choice.
The ecoSwitch app, developed by the George Institute for Global Health, rates dairy milk at 85 out of 100 for environmental performance, compared to 96 for soy milk. Oat and almond milks are not yet rated due to data gaps, but soy is considered representative of plant-based options.
While plant-based milks generally have a lower environmental footprint, experts caution that choices should also consider nutritional needs and local water scarcity. The findings reflect a broader shift in consumer habits, with Australian dairy milk consumption falling from 100 litres per person in 2015 to 85 litres by 2025.
