How could this be done? According to a recent peer-reviewed study at the University of Oxford, a plant-based diet accounts for 75% less greenhouse gas emissions than the diet of someone who consumes more than 3.5 ounces of meat a day (Scarborough, 2023). The above chart shows a total of 52.4 billion tons of CO₂e, but that comes from 2018 data (the chart is still useful as the relative percentages of emission sources is about the same today), so we will use the 2022 number of 59 gigatons (Rothenberg, 2023). If the 26% of the 59 gigatons of CO₂e global emissions come from animal agriculture, that gives us roughly 15.3 gigatons of CO₂e. Multiply that by one quarter, and we have 3.8 gigatons. That means our new total percentage of emissions due to agriculture would be 3.8/47.5 (the 47.5 gigatons comes from 59-(15.3-3.8)=47.5), which comes out to 8.0%. In summary, this means that if the global population shifted to a plant-based diet, CO₂ emissions would be down a massive 18 percent! That’s more than all emission due to transportation (cars, trains, planes, etc), which account for 16.2% of global emissions (Ritchie, 2020).

Of course, this change would never happen overnight. That doesn’t mean it shouldn’t be pursued at all, however. In fact, no meaningful positive change for the environment will happen overnight, and certainly not the global shift to electric vehicles and a solar/wind powered electric grid. To best protect our world, the environment, and our future, all of these reductions in emissions should be pursued in tandem and with great vigor.

Not convinced that an 18% decrease in global greenhouse gas emissions is enough of an incentive to change your diet? Well, you’re not alone. After all, 80% of the world’s population has been eating meat, dairy, and eggs their entire lives. It’s a deeply ingrained and accepted aspect of society. But should it stay that way?

You may have noticed that so far this article has often referred to a plant-based diet, but it has not used the words: vegan diet. Don’t these mean the same thing? What is a vegan, anyways? According to the Vegan Society:

            “Veganism is a philosophy and way of living which seeks to exclude—as far as is possible and practicable—all forms of exploitation of, and cruelty to, animals for food, clothing or any other purpose…” (Definition of Veganism, 1988).

This means that someone who is vegan has not just made a diet change, but also follows an ethical principle to avoid the exploitation of animals. This means a vegan would also not buy or wear leather, purchase a dog from a breeder (adopt don’t shop!), or visit/support a zoo. Your initial reaction might be that this sounds preachy and annoying, but bear with me for a moment.

If you’ve made it this far in this article, odds are that you are an individual who cares about and is motivated to prevent climate disaster and protect our environment. Still, you may be wondering: “Why should I change my lifestyle so dramatically for a cause that only accounts for 18% of global carbon emissions?” That’s a good question, but first it is worth asking yourself why you are so motivated about protecting the environment to begin with.

Perhaps you are motivated by empathy when you hear the tragic mating call of the last Kaua’I ‘o’o bird, a species that, like over 880 other animals species (that we know of), is now extinct due to humans. Perhaps you are motivated by the fact that over 1 million plant and animal species are threatened with extinction within the next few decades (United Nations, 2019). Perhaps you are motivated by rainforest deforestation (Cattle ranching is responsible for 80% of rainforest deforestation across all Amazon countries (Amazon Aid, 2022)). Or perhaps you are simply motivated by a desire to not see humanity itself go extinct itself.