Vegan diets aren’t always better?
One of the reasons I initially turned vegetarian was after learning about the environmental cost of the beef industry: livestock production accounts for almost 18 % of all greenhouse gases. Here in Ireland, the meat and dairy industry really packs a punch on the environment. Livestock farming alone makes up about a third of our national greenhouse-gas emissions—mostly methane from cows and nitrous oxide from fertilised fields—and that drives climate change more than any other sector. On top of that, managing all that manure and slurry leaks nitrogen and phosphorus into our rivers and lakes, fueling algae blooms and hurting aquatic life. Intensifying dairy herds to meet global demand also means more tractor traffic, which compacts the soil and reduces its ability to soak up rain, increasing flood risks. Ireland’s love of meat and milk comes with a pretty big ecological price tag.
I’ve always heard that the answer to this problem was simply “go vegan.” While I was never strong enough to go fully vegan myself, I did think that going vegetarian was at least partly helping out. Recently, however, I came across a BBC article titled “Why the vegan diet is not always green” that made me think about whether vegan is really that much better. While a vegan diet generally outshines meat in cutting greenhouse-gas emissions, not all vegan staples are low-impact:
Air-freighted produce (e.g., off-season berries, asparagus) can emit more CO₂ per kilo than some meats.
Water-thirsty crops like avocados (up to ~834 L/kg) and mangoes (~686 L/kg) put huge strain on water-stressed regions.
Energy-hungry cultivation: mushrooms require heated, high-CO₂ grow rooms, and synthetic fertilizers plus tilling release CO₂ and nitrous oxide.
Processing overhead: mycoprotein products can rack up 5.5–6 kg CO₂/kg, half of which comes from post-fermentation processing.
Deforestation for commodities like cocoa drives massive biodiversity loss and can add 11 kg CO₂/kg for chocolate.
Tree nuts (almonds, cashews) demand large water and fertilizer inputs, though their dense nutrition can justify the footprint if you’re mindful of sourcing.
All in all, a plant-based diet is a powerful climate move, to maximise benefits, favour local, seasonal produce, minimise air-freighted or heavily processed items, and be conscious of water-intensive or deforestation-linked crops.
