You might have heard that a plant-based diet is better for the environment and wondered where nuts fit in, as there are many claims about almonds being bad for the environment.
While some nuts, like almonds, have a big environmental footprint, other kinds, like chestnuts and peanuts, are more sustainable.
Nuts may not be good for the environment, but overall, they’re a more sustainable protein than animal products.
Note: Although peanuts are not nuts but legumes, we still included them in this article since most people regard them as nuts.
Here’s everything you need to know about the environmental impact of nuts.
1. How Do Nuts Affect the Environment?
One of the biggest ways food impacts the environment is transport, as you can find food in your grocery store from all over the world that cannot be grown in your region’s climate.
Food miles refer to how far food travels before getting to consumers’ plates; approximately 6% of greenhouse gas emissions are due to food transportation.
Research found that emissions stemming from food emissions could be reduced by 0.11 GtCO2e and food mile emissions by 0.27 GtCO2e if we were to rely on domestic food.
Many nuts are grown in tropical regions. For example, most of the world’s almonds and pistachios are grown in California.
Even though Spain also produces almonds, the country still imports almonds from California.
Peanuts are also suited to warmer climates, with most peanuts grown in southern US states like Texas, as well as in Asia, Africa, and South America.
Most hazelnuts are grown in Turkey, and Brazil nuts in Brazil, Peru, and Bolivia. Chestnuts are mostly grown in China, Korea, and Portugal.
So, unless you know the nuts were grown locally, they likely traveled a long way before arriving on your grocery store’s shelves.
Not all nuts are grown and harvested the same.
However, some kinds of nuts are often grown as mono-crops, meaning they are the only crop grown in the area.
Monocrops are bad for the environment because they reduce biodiversity, which can leave animals and insects without food and shelter as land is cleared to make way for commercial farming.
Biodiversity can protect plants from pests and disease.
Moncropping can generate huge amounts of waste as it is much easier for pests or diseases to spread throughout the crop, rendering it useless.
This farming method can also leave the soil depleted of nutrients, which reduces the lifespan and yield.
Different kinds of nuts will also have different water requirements.
The water use can also vary depending on species, climate, rainfall, and whether they are organic.
Hazelnuts grown in Oregon in the US were initially grown without the need for irrigation, but as the climate becomes hotter and drier, this has become a more common practice.
In terms of water consumption, cashew nuts perform the worst: at 45,914 liters per kg, they consume the most by far.
They are followed by almonds, pistachios, hazelnuts and walnuts.
Conversely, chestnuts have by far the lowest water consumption per kg, and peanuts also consume significantly less water than the other types of nuts mentioned.
Nut crops can also be treated with pesticides, which can be harmful to the environment.
Pesticides can cause pollution due to run-off and are also harmful to pollinators such as bees.
Exposure to pesticides can reduce populations of these insects, which leaves plants unpollinated.
By extension, this can also mean less food for other animals due to lower yields of other crops and plants in the area.
2. What’s the Carbon Footprint of Nuts?
The carbon footprint of nuts varies depending on the variety and growing region.
A study examined the net CO2 emissions per kilogram of raw nuts.
It turned out that cashew nuts and almonds cause the highest CO2 emissions, followed by pistachios.
Hazelnuts and peanuts, on the other hand, cause significantly less CO2 emissions.
For chestnuts, a Portuguese study found a very wide range of 0.4-2.7 kg CO2e per kg due to different cultivation methods (which is why they are not included in the chart).
Depending on how the nuts are processed, the post-harvest carbon footprint can increase even further as more energy is required to shell, roast, or process nuts into pastes and spreads.
The researchers also pointed out that the carbon footprint of growing nuts could be significantly reduced by energy recovery of the fruit shells.
Because CO2 is bound in the shells, it is released when the shells are left to rot.
3. Which Nuts Are the Most Sustainable?
Cashew nuts, almonds and pistachios use the most water and cause the highest CO2 emissions per kilogram.
At the other end of the spectrum, peanuts, hazelnuts, walnuts and chestnuts use the least water and have the smallest carbon footprint.
When assessing their sustainability, it is also interesting to see how nuts perform as a protein source compared to animal alternatives.
Comparing the water consumption per gram of protein, peanuts are the most water-efficient protein source, while cashews are again the worst in this category.
Besides water consumption, greenhouse gas emissions are of course particularly relevant for assessing the climate effects of different foods.
As this study shows, the contribution of nuts to global warming is negligible compared to animal protein sources.
In the face of the enormous amounts of greenhouse gases emitted by the meat industry, the contribution to global warming by even the most “polluting” nuts such as cashews or almonds ist vanishingly small.