The food we consume has a massive impact on our planet. Agriculture takes up half the habitable land on Earth, destroys forests and other ecosystems, and produces a quarter of the world’s greenhouse gas emissions. Meat and dairy specifically account for around 14.5 percent of global greenhouse gas emissions.
So changing what we eat can help reduce carbon emissions and promote sustainable farming. But there are several “climate-friendly” diets to choose from. The best known are the completely plant-based vegan diet, the vegetarian diet (which also allows eggs and dairy) and the pescetarian diet (which also allows seafood).
Which diet should you choose?
Let’s start with a new fad: the climatarian diet. One version was created by the not-for-profit organization Climates Network, which says this diet is healthy, climate friendly and nature friendly. According to the publicity, “with a simple diet shift you can save a tonne of CO₂ equivalents per person per year” (“equivalents” just means methane and other greenhouse gases are factored in alongside carbon dioxide).
Meat, especially highly processed meat, has been linked to a string of major health issues including high blood pressure, heart disease and cancer.
Sounds great, but the diet still allows you to eat meat and other high-emission foods such as pork, poultry, fish, dairy products and eggs. So this is just a newer version of the “climate carnivore” diet except followers are encouraged to switch as much red meat (beef, lamb, pork, veal and venison) as possible to other meats and fish.
The diet does, however, encourage you to cut down on meat overall and to choose responsibly produced and local meat where possible, in addition to avoiding food waste and consuming seasonal, local foods.
So saving a tonne of carbon dioxide is great but switching to vegetarianism or veganism can save even more. A Western standard meat-based diet produces about 7.2 kilograms of CO₂ equivalent per day, while a vegetarian diet produces 3.8 kg and a vegan diet 2.9 kg. If the whole world went vegan, it would save nearly 8 billion tonnes CO₂equivalent — while even a switch to the Mediterranean diet would still save 3 billion tonnes. That is a saving of between 20 and 60 percent of all food emissions, which are currently at 13.7 billion tonnes of CO₂equivalent a year.
Plant-based diets can save water and land — and they’re healthier
To save our planet, we must also consider water and land usage. Beef, for instance, needs about 15,000 liters of water per kilo to produce. Some vegetarian or vegan foods like avocados and almonds also have a huge water footprint, but overall a plant-based diet has about half the water consumption of a standard meat-based diet.
A global move away from meat would also free up a huge amount of land, since billions of animals would no longer have to be fed. Soy, for instance, is one of the world’s most common crops, yet almost 80 percent of the world’s soybeans are fed to livestock.
The reduced need for agricultural land would help stop deforestation and help protect biodiversity. The land could be used to reforest and rewild large areas, which would become a natural store of carbon dioxide.
One study suggests a move to a global plant-based diet could reduce global mortality by up to 10 percent by 2050.
What’s more, a plant-based diet is generally healthier. Meat, especially highly processed meat, has been linked to a string of major health issues, including high blood pressure, heart disease and cancer. One study suggests that a move to a global plant-based diet could reduce global mortality by up to 10 percent by 2050.
However, meat, dairy and fish are the main sources of some essential vitamins and minerals such as calcium, zinc, iodine and vitamin B12. A strict vegan diet can put people at risk of deficiencies unless they can have access to particular foods or take supplements. Yet both supplements and vegan food products are too expensive or difficult for many people around the world to access, and it would be hard to scale up supplement production to provide for billions of extra people.
So a climatarian or flexitarian approach means there are fewer health risks but it still allows people to exercise choice.
We slaughter around nine animals per person per year — even though the same nutrients can come from plants
One issue that seems to be missing from many food discussions is the ethical dimension. Every year we slaughter 69 billion chickens, 1.5 billion pigs, 0.65 billion turkeys, 0.57 billion sheep, 0.45 billion goats and 0.3 billion cattle for food worldwide. That is over nine animals killed for every person on the planet per year — all for the nutrition and protein that we know can come from a plant-based diet.
So what is the ideal global diet to reduce greenhouse gas emissions, reduce habitat destruction and help you live longer?
Well, I suggest being an “ultra-flexitarian,” a diet of mostly plant-based foods but one that allows meat and dairy products in extreme moderation, with red and processed meat completely banned. This would save at least 5.5 billion tonnes of CO₂ equivalent per year (or 40 percent of all food emissions), decrease global mortality by 10 percent, and prevent the slaughter of billions of animals.
Watch Mark Maslin’s TEDxKingsCross Talk: