Editor's Note: (George C. Wang, M.D., Ph.D., is a geriatrician and integrative medicine physician, assistant professor of medicine at Columbia University Medical Center, and adjunct assistant professor of medicine at Johns Hopkins University School of Medicine. The opinions expressed in this commentary are his.)
(CNN) As public attention focuses on the impact of policy changes on the climate, we may overlook an important contributor to the climate crisis: our food systems and the daily food choices we make. It may sound hyperbolic that our roast beef sandwich is contributing to environmental degradation of the planet. But mounting evidence of the impact requires our attention and action as global citizens.
And each of us can do something about it, today, by taking what we eat as seriously as we take climate change.
An assessment by the Food and Agriculture Organization of the United Nations indicated the contribution of the livestock sector to global greenhouse gas emissions exceeds that of transportation.
Emissions from the production of beef and lamb are 250 times higher than those from legumes, per gram of protein, and pork and poultry are 40 times higher than legumes. A large amount of methane and nitrous oxide, gases that are more than 20 times and 250 times more powerful than carbon dioxide as a greenhouse gas, are generated through livestock-raising activities.
The effect of greenhouse gas emissions seems like an intransigent problem to curb, much less to solve. How can we play a role in influencing what humans are doing to the planet? And how can we approach these issues when political and economic forces can undermine efforts to address the climate crisis?
One answer lies in the choices that we make every day: what we eat.
A study published in Nature found that, by 2050, a projected 80% increase in global greenhouse gas emissions from food production can be avoided, if the global diet is an equal-parts mixture of the Mediterranean, pescetarian and vegetarian diets.
Within that spectrum, fewer animal products are what's best for the planet, and our collective future. The Mediterranean diet alone (one that includes lower amounts of animal products) will still result in increased emissions, and the pescetarian diet (a vegetarian diet that includes fish) will lead to only a small degree of reduction in emissions.
However, a global vegetarian diet, the same study showed, would be the most effective of all diets (not including vegan) in achieving a reduction in greenhouse gas emissions, as well as a decrease in agricultural land demand and land clearing.
It follows that the vegan diet, by eliminating dairy and egg, would reduce emissions the most, as confirmed by a subsequent study. Adopting a plant-based diet is, therefore, one of the most powerful choices an individual can make in mitigating environmental degradation and depletion of Earth's natural resources.
Beyond contributing significantly to greenhouse gas emissions that cause rising temperatures and sea levels, here's what eating meat also does to our world: While almost 800 million people suffer from chronic undernourishment and insecure food supplies, 35% of grains worldwide are fed to livestock.
About 80% of all Amazon deforestation is due to cattle-raising. Meanwhile, livestock production plays an important role in the global biodiversity crisis that we are now facing, unprecedented since the end of the last ice age.
So, what keeps us from following a plant-based diet? It requires overcoming our habits and our tastes, learning new ways to cook, planning during travel, and navigating the social aspects of eating and meal sharing. However, when seen through the lens of the fate of Earth's climate and resources, don't these challenges all of a sudden seem minuscule?
Choosing plant-based diets can promote environmental sustainability.
It is rare that a single choice of ours can have a broad and decisive impact on the climate crisis. We have a moral imperative to choose and advocate for plant-based diets for the health of our planet and the well being and survival of generations to come.