In other words, the vegan diet scenario would be best for the environment. The authors also note that the VGN estimate is likely conservative because they "did not account for the beneficial impacts of dietary change on land use through avoided deforestation."
The risks involved with continuing our current system of animal agriculture are becoming increasingly evident with new research. Over the past decade, in particular, numerous studies have looked at the havoc that animal agriculture is wreaking on the planet. Most have them have concluded, to varying degrees, that consuming meat and other animal products has been a major contributor to greenhouse gas (GHG) emissions and climate change problems. Other studies have similarly shown that reducing the amount of animal products we consume could ease pressure on land use, reduce GHG emissions, and improve our personal health (not to mention the positive impact for animals).
Still, not all analyses of how diet impacts the environment are the same. Some are focused on water usage, others on GHG emissions, and still others on economics. In this study, researchers combined environmental and economic analyses. For the former, they connected "data from regional and scenario-specific food type consumption levels to GHG emissions" while also adjusting "for likely future productivity improvements." For the economic analysis, they placed "a monetary value on changes in GHG emissions" through "estimates of the social cost of carbon," as well as "monetizing the health consequences" of eating meat. The researchers used this "coupled modeling framework" to then analyze the environmental and health impacts of "four dietary scenarios in the year 2050."
Scenario one, referred to as REF was "a reference scenario based on projections from the Food and Agriculture Organization of the United Nations." The second scenario, called "healthy global diets or HGD", assumes the adoption of "global dietary guidelines on healthy eating." The final two scenarios look at lacto-ovo vegetarian diets (VGT) and completely plant-based (VGN) diets. Overall, the researchers found that baseline emissions (REF) are expected to increase by 51% between now and 2050. Depending on the scenario, dietary changes could reduce these reference emissions anywhere from 29% (HGD) to 70% (VGN). In other words, the vegan diet scenario would be best for the environment. The authors also note that the VGN estimate is likely conservative because they "did not account for the beneficial impacts of dietary change on land use through avoided deforestation."
Regarding health, the authors say that "changes in the consumption of red meat, fruits, and vegetables and in total energy intake could result in reductions in total mortality of 6–10%," but that they were not able to model the health consequences of all food groups. The implication, however, is that vegetarian and vegan diets could result in avoiding 7.3 million and 8.1 million deaths, respectively. Regarding costs, they found that "the economic value of the health benefits associated with more plant-based diets is comparable with, or exceeds, the value of the environmental benefits." Although there are many factors at play, changing to a vegan diet could result in savings in the upper billions, or even trillions, of dollars.
For animal advocates, this is more than just another study about the dangers of animal agriculture to our planet. This research offers a comprehensive analysis, places a price tag on the environmental impacts of animal agriculture, and looks specifically at how vegan and vegetarian diets can be beneficial. Over and over, in category after category, the researchers find that "changes toward fewer animal and more plant-based foods are associated with significant benefits due to reductions in diet-related mortality and GHG emissions." What's more, they note that "the size of the projected benefits, even taking into account all of the caveats about the unavoidable sources of uncertainty in our work, should encourage researchers and policy-makers to act to improve consumption patterns." The evidence is clear, but will policy-makers listen?
Access to entire article - Analysis and valuation of the health and climate change cobenefits of dietary change