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  • Raghav Sand

Will Going Vegan Save Our Planet?

Greenhouse gas (GHG) emissions in the food system came from – ranging from deforestation and land use, through to transport and packaging. The climate impact of diets is usually compared in terms of GHG that are emitted today. But this misses a hidden cost: the carbon opportunity costs of agricultural land.

Meat and dairy products need more land than alternatives, and therefore have a higher opportunity cost. Going vegan, would result in the largest carbon savings, but even just a reduction of meat and dairy consumption – without eliminating it completely – can also have a massive impact. In fact, a diet that replaces chicken for beef and cuts out dairy would achieve almost as much as a fully vegan diet.

Over the last several centuries, agricultural land has expanded into forests, wild grasslands and other ecosystems. The world lost one-third of its forests, and today agricultural land makes up half of the world’s ice- and desert-free land. The loss of these forests and other natural vegetation has released a lot of carbon into the atmosphere.

It can be easy to forget about these emissions that happened decades, centuries, or even millennia ago. We tend to only focus on emissions today. This undersells the role that our agricultural land use could play in tackling climate change. An opportunity cost is the potential benefit you’re giving up by choosing one option over the other. Every decision you make has an opportunity cost – you could be spending your time or money on something else. Spending time watching television comes at the ‘cost’ of not reading a book or not visiting a friend.

Do we need to go vegan to make a big difference? The specific number that answers this question depends on these three factors, but the range of possible answers is not too large: around 25% to 30% of global emissions come from our food systems, and this rises to around one-third when we include all agricultural products.

In the standard framework of counting greenhouse gas emissions, opportunity costs are not taken into account. The ‘carbon footprint’ figures usually reported for different foods are based on greenhouse gas emissions today: how much nitrous oxide is produced when we add fertilizers; methane released by cows; carbon released when we cut down forest and replace it with crops.

Of course, CO2 in the atmosphere is not the only metric we care about: there is a complex range of socioeconomic factors (such as the livelihoods of people who work in the farming sector) to consider. It’s up to society to decide what it should do, given the choices available. People are becoming increasingly aware that their diet comes with a climate cost.

For proper nutrition and health we need to eat a diverse range of foods. Our food system is currently responsible for 13.7 billion tonnes of carbon dioxide equivalents (GtCO2e) each year. That’s one-quarter (26%) of total greenhouse gas emissions. If people decided to cut out beef and lamb, we would reduce emissions by 2.6 GtCO2e per year (a 20% reduction), and save an additional 4.5 GtCO2e by restoring vegetation on abandoned farmland. If we also cut out dairy we could save 12.3 GtCO2e each year – almost as much as global food emissions today.

What’s interesting is that most of the carbon reductions come from cutting out beef and dairy. This means substituting chicken, pork, fish or plant-based substitutes is the most effective way to reduce the land use and carbon impact of your diet. Thankfully there is no trade-off between production emissions and opportunity costs: what reduces emissions the most also results in the greatest reduction in opportunity costs. Shifting to a more plant-based diet achieves both.

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