Shifting to a diet rich in plants is a demand side solution to global warming that runs counter to the meat centric, highly processed, often excessive western diet broadly on the rise today.
That western diet comes with a steep climate price tag. The most conservative estimates suggest that raising livestock accounts for nearly 15 percent of global greenhouse gases emitted each year; the most comprehensive assessments of direct and indirect emissions say more than 50 percent...
Ruminants such as cows are the most prolific offenders, generating the potent greenhouse gas methane as they digest their food. In addition, agricultural land use and associated energy consumption to grow livestock feed produce carbon dioxide emissions, while manure and fertiliser emit nitrous oxide. If cattle were their own nation they would be the world’s third largest emitter of greenhouse gases...
According to the World Health Organisation, only 10 to 15 percent of one’s daily calories need to come from protein, and a diet primarily of plants can easily meet that threshold.
A ground breaking 2016 study from the University of Oxford modelled climate, health and economics benefits of a worldwide transition to plant based diets between now and 2050, Business-as-usual emissions could be reduced by as much as 70 percent through adopting a vegan diet and 63 percent for a vegetarian diet (which includes cheese, milk and eggs). The model also calculates a reduction in global mortality of 6 to 10 percent. Dietary shifts could be worth as much as 13 percent of worldwide gross domestic product in 2050... Beyond promoting “reducetarianism”, if not vegetarianism, it is also necessary to reframe meat as a delicacy, rather than a staple. Few climate solutions of this magnitude lie in the hands of individuals or are as close as the dinner plate.
Using country level data from the Food and Agriculture Organisation of the United Nations, we estimate the growth in global food consumption by 2050, assuming the lower income countries will consume more food overall and higher quantities of meat as economies grows. If 50% of the world’s population restricts their diet to a healthy 2,500 calories a day and reduces meat consumption overall, we estimate at least 26.7 gigatonnes of emissions could be avoided from dietary change alone. If avoided deforestation from land use change is included an additional 39.3 gigatonnes of emissions could be avoided making healthy plant-rich diets one of the most impactful solutions at a total of 66 gigatonnes reduced.
“Drawdown: the most comprehensive plan ever proposed to reverse global warming”, pp. 39-40.