With a world population pushing past seven billion on its way to who knows what, and an increasing demand for farmland, forests around the world are under pressure. Though roughly thirty percent of the world’s land is still covered in forest, in many areas that forest is sliced through by roads, chopped into by farms, clear cut for lumber, and simply encroached on by human habitation. The result is that much of the world’s forest has been forced into “islands” which are separated from one another by lanes of human activity. This reduces the overall health of the forest, and by limiting the range of animal populations makes them much more susceptible to localized conditions.
Forests support the most diverse populations of plants and animals found on land, but forests also produce a relatively low energy per acre when it comes to making food. So … if we’re going to feed an ever-growing human population, does that mean a world where trees are pulped to make room for more cropland. Not necessarily. According to new research, we can keep the people and the trees.
Safeguarding the world’s remaining forests is a high-priority goal. We assess the biophysical option space for feeding the world in 2050 in a hypothetical zero-deforestation world. We systematically combine realistic assumptions on future yields, agricultural areas, livestock feed and human diets. For each scenario, we determine whether the supply of crop products meets the demand and whether the grazing intensity stays within plausible limits.
You can get a solution that will please both the lunch crowd and the Lorax, but we have to be careful.
Researchers went though more than 500 scenarios, playing out statistical models of how cropland, grazing areas, and forests interact. The good news—make that the great news—is that over half of these scenarios were winners. That is, they provided adequate crops without substantially reducing forested areas. There were winning scenarios down the road where everyone becomes a vegan and insists on organic crops, but there were also winning paths that included substantial portions of animal-based protein in the diet and GMO crops. There were winning scenarios that included a mixed selection.
However, not every scenario was equal. Forty percent wouldn’t work at all. And of those that did work, some worked only by their fingernails. On the one end of the spectrum, there were some very good results.
... all VEGAN scenarios and 94% of the VEGETARIAN scenarios are feasible,
Removing land set aside for grazing cattle and raising animals allowed people to be fed and wild areas to be retained … every time. Scenarios where people refused to surrender their cheeseburgers tended to be less successful. Of those scenarios that assumed a RICH diet (one that’s close to that of Americans today) as the global standard, only 15 percent of scenarios were both successful in producing enough food and preserving wild areas. The biggest reason, well …
Grazing constraints strongly limit the option space.
That would translate to “add a billion cows to the mix, and good luck finding a tree still standing.” While there are many non-vegetarian scenarios that work, getting a large percentage of protein from cattle or other grazing animals just places too high a constraint on the system. With few exceptions, grazing land is also potential crop land, and even low-yield crops still produce more food per acre than you get by running the whole process through a cow.
How crops were produced also made a significant difference. Using crop yields equivalent to the highest for each of the major food crops turned 79 percent of scenarios into winners. Enforcing an organic-only rule and typical yields dropped that count to 39 percent.
One of the trends of the last century has been a “converging diet.” That is, the world population increasingly gets its calories from a very few major food crops. This is a problem because, no matter how you dice up the space, only so much of it is appropriate for growing corn, rice, wheat, and soybeans, and some of the space you need is under wilderness. In just about every case, having a world that moved toward not just “everyone gets a good diet” to “everyone eats the same diet” was a loser.
So it’s not that surprising that one of the most consistent winners is a diet labeled BAU. That’s not some strange diet composed of bacteria, alligator, and unidentifiable materials. It’s “business as usual.” In this case, it means giving everyone a good diet, with both more calories and more protein than are now consumed on average, but keeping that diet more similar to the existing mix of sources instead of forcing everyone to dine like all restaurants are Taco Bell.
… the maximum cropland demand of the RICH diet is similar to the maximum of the BAU diets. However, here, the number of feasible scenarios is considerably reduced by grazing constraints. RICH diets are feasible only with considerable cropland expansion and high cropland yields, whereas the other diet variants are also feasible with low or moderate levels.
In the worst case, a BAU diet can take pretty much the same space as a RICH diet, but because a BAU diet is much more varied in both the crops and the animals it uses, there are a lot more possibilities for fitting it around existing wilderness rather than over.
There’s no doubt about it, you can feed the planet on a vegan diet. You can also feed the planet on a vegetarian diet that includes animal protein sources such as eggs. Perhaps the best news is the success of the BAU solutions: you’ve got about a two thirds chance of both keeping wilderness and feeding the population using a diet that employs a wide variety of food crops and protein sources which vary by region. That’s a scenario that preserves not just wilderness, but diversity in our diets … and in our culture. That has a value that’s hard to measure. Like a forest.
What you can’t do: feed the world like we currently feed America. And honestly, we shouldn’t do it to America, either.