Soy milk vs Almond milk: Carbon Footprint Compared

Choosing between soy milk vs almond milk is no longer just a matter of taste or nutrition; for many, it is a conscious environmental decision. As more people move away from dairy—which carries a significantly higher carbon footprint than any plant-based alternative—the debate has shifted to which plant milk reigns supreme for the planet.

While both milks are vastly better for the Earth than cow's milk, they impact the environment in different ways. Soy milk is often lauded for its high protein content and land efficiency, whereas almond milk is frequently criticized for its extreme water consumption despite having a very low greenhouse gas emission profile.

The Numbers: Greenhouse Gas Emissions Compared

When we look strictly at carbon dioxide equivalents (CO2e), the comparison between soy milk vs almond milk reveals that both are climate leaders, though almond milk technically has a slightly lower emission profile per liter.

According to data from the University of Oxford (Poore & Nemecek, 2018), here is how they stack up per 1,000ml (1 liter) of milk:

• Soy Milk: ~0.98 kg CO2e per liter
• Almond Milk: ~0.70 kg CO2e per liter

For context, a single liter of conventional dairy milk produces approximately 3.15 kg CO2e. This means that switching from dairy to either soy or almond milk reduces your beverage-related carbon footprint by over 68%.

While almond milk wins on pure carbon emissions, the "footprint" of a food item includes more than just gas. Almonds require significantly more water—roughly 371 liters of water per liter of milk produced—compared to just 28 liters for soy milk. Therefore, if you live in a water-stressed region like California (where 80% of the world's almonds are grown), the carbon-only metric may be misleading.

Why the Difference in Environmental Impact?

The disparity in the soy milk vs almond milk comparison comes down to how these crops are grown and processed.

The Case for Soy

Soybeans are legumes, which means they have a unique environmental advantage: nitrogen fixation. Soybeans take nitrogen from the atmosphere and turn it into nutrients in the soil, reducing the need for synthetic nitrogen fertilizers. Since the production and application of synthetic fertilizers are major sources of nitrous oxide (a potent greenhouse gas), soy has a built-in efficiency. However, the carbon footprint of soy is slightly higher than almond because of the energy required to grind, cook, and process the beans into a shelf-stable liquid.

The Case for Almonds

Almond trees act as a "carbon sink" to a certain extent. Because they are perennial trees that grow for 25 years or more, they store carbon in their woody biomass throughout their lives. This sequestration helps offset some of the emissions from harvesting and transport. The primary reason almond milk has lower emissions than soy is that the "milk" itself is highly diluted; many commercial almond milks contain only 2% to 5% almonds, meaning fewer raw materials are transported per liter of finished product.

Land Use and Biodiversity

Soy is often associated with deforestation in the Amazon. However, it is critical to note that roughly 77% of global soy is grown for livestock feed, not human consumption. Soy milk is typically sourced from beans grown in the US, Canada, or Europe, which are not linked to tropical deforestation. Almonds, meanwhile, require massive monoculture orchards that can be detrimental to local bee populations due to the intensity of the pollination season and pesticide use.

What You Can Do

If you are trying to minimize your environmental impact, the soy milk vs almond milk debate shows that you are already on the right track by avoiding dairy. Here are three ways to optimize your choice:

1. Prioritize Local and Organic: Check the label for the origin of the main ingredient. Soy grown in your region will always have a lower transport footprint than almonds shipped across an ocean.
2. Consider Water Scarcity: If you live in an area prone to drought, soy milk is the ethically superior choice due to its drastically lower water requirements.
3. Minimize Waste: Regardless of which milk you choose, the packaging (usually Tetra Paks or plastic bottles) contributes to the footprint. Opt for larger containers to reduce the surface-to-volume ratio of packaging, or try making your own at home using a high-powered blender and a nut milk bag.

By understanding the nuances of these plant-based alternatives, you can make a choice that aligns with your personal values and regional environmental needs.

To see how your milk choice fits into your overall lifestyle, visit our calculator to estimate your own carbon footprint.