We'd need another Canada-sized chunk of fertile land, scientists say, in order to meet those requirements.
If the entire world were to follow the United States' recommended dietary guidelines, there would not be enough land to grow it all. In fact, an additional gigahectare of fertile land would be needed to produce that much food, roughly the size of another Canada (3.8 million square miles).
Researchers from the Universities of Guelph and Waterloo in Ontario, Canada, examined crop yield data at national, continental, and global levels. They based their study on U.S. dietary guidelines because those were most readily available when the study began six years ago. What they found was a bigger problem than what they'd expected. As they wrote in the scientific journal PLOS ONE:
"Our analysis shows that there is not enough land for the world to adhere to the USDA guidelines under current agricultural practices. This is despite the fact that the USDA guideline diet is already less land-intensive than the current U.S. diet."
What that means is that, even if inhabitants of North and South America and Oceania reduced their meat consumption to meet guideline levels (they currently exceed those amounts considerably), extra land would still be needed in order for inhabitants of Africa, Asia, and the European Union to increase meat intake to meet guidelines levels. Specifically, "Australia, Brazil and the United States could spare the most land, while India, Mozambique and Saudi Arabia required the most land to meet the USDA guidelines." (via CBC)
One obvious problem is that the U.S. dietary guidelines are hardly considered a pinnacle of health, even if they are prominent and well-entrenched. The study owners are aware of this, pointing out that a better model does exist:
"The fact that Europe is sparing land by avoiding a USDA guideline diet suggests that there may be sustainable ways to improve diets in the poorest countries avoid malnourishment, while also sparing land compared to the USDA guideline diet."
The two concluding recommendations are:
1) The formulation of dietary guidelines must be based on more than human physical health. It should include consideration of sustainable global land use, equity, and natural ecosystem conservation.
2) Dietary guidelines should be coordinated internationally. Since international agricultural trade is growing and fertile land is in increasingly high demand, this would "incentivize country-level improvements in dietary habits that result in global land sparing, similar to how countries are beginning to coordinate reductions in their greenhouse gas emissions."
This is all very fascinating, since health and the environment are usually addressed as separate issues, while in reality they're deeply intertwined. What we eat shapes the land around us, and as the land degrades so will our health inevitably.
Study co-author Evan Fraser described the findings as a "wakeup call". He was quoted by CBC:
"Feeding the world over the next generation is one of the biggest global challenges that we face. And this is not an easy problem to solve. It's right up there with climate change and international trade issues and all these big, thorny issues of the 21st century. [This study] gives us some sense of the scale of the problem."
It would make sense, then, that eating a more planet-friendly diet is the logical way forward, as no extra Canada-sized chunks of land are about to appear out of nowhere, nor will the atmosphere thank us for perpetuating the current state of agriculture. The study reminds us that "global agricultural production accounts for nearly 30% of total greenhouse gas (GHG) emissions [and] livestock alone are responsible for 18% of GHG emissions, which is higher than the share from transportation."
Is it our job to eat less meat in order to free it up for people with protein-deficient diets? Or do we reduce meat consumption for the sake of shrinking our individual footprints and attempting to slow global warming? Perhaps we eat less meat because we believe it's healthier, contrary to what the USDA guidelines may tell us. There's no right answer -- no doubt each person will have their own opinion -- but the point is that we do need to think about it.
Because if we don't start thinking about health in terms beyond our physical bodies, we'll soon be forced to, and that will be a whole lot harder.