Feeding The World Without Destroying Forests

Safeguarding the world’s remaining forests is often touted as a high-priority environmental goal, both for the general health of the planet, and for wildlife conservation. However, as global population continues to climb and present various problems of scale, the hope of feeding this growing population without further environmental degradation seems increasingly unlikely. Enter a team of researchers from Austria, who sought to assess the options for feeding the global population in 2050 in a hypothetical zero-deforestation world. Realistic assumptions on future yields, agricultural areas, farmed animal feed and human diets were systematically combined to provide 500 scenarios for testing.

The researchers kick-off by issuing an update: three-quarters of Earth’s ice-free land surface is currently under human use. It is well known that human land use is associated with many negative environmental effects such as pollution, biodiversity loss, climate effects or eutrophication (the release of an excessive amount of nutrients in water which leads to a overly dense growth of plant life). In certain areas, these effects have reached levels that actually jeopardize entire ecosystems, and it is especially apparent in forest areas. Forests store more carbon than any other land-cover type per unit of area and, of course, are home to a considerable portion of global species biodiversity. Apparently, a sizeable fraction of global pristine forests have already been converted into agricultural land, mostly in the tropics. The researchers build on top of recent studies which suggest that providing sufficient food without cropland expansion is possible.

In their calculations, the scientists explore the individual roles of supply-side measures such as increasing cropland yields, the cropland area size itself, the efficiency of animal farming systems, and demand-side measures (such as changes in the human diet). For each of these parameters, published forecasts for the year 2050 were collected and incorporated into the model. The researchers define ‘feasibility’ of a scenario as a situation in which global food demand is matched while cropland supply and animal grazing intensity stays within ecological thresholds.

The results should be uplifting for animal advocates: a large range of options exist to feed the world on a no-deforestation model. However, the combination of low cropland-yields and an average diet similar to that of North America was not among the ‘feasible’ ones. While vegan or vegetarian scenarios, were 100% or 94% feasible, respectively, only a small fraction of the North American diet scenarios were found to be feasible.

The results suggest that ruminant-based animal systems are primarily confronted with grazing constraints, whereas grain-based feeding faces cropland constraints. It is noteworthy that the effect of reduced grazing area availability can be compensated, for example, by lower demand for animal products. The use of land that is not directly usable for food production with ruminants could hold important food security potential, though. While on the topic of land, however, vegan diets were found to require less cropland than in the reference year 2000, while the meat-reliant alternatives reached 52% above the current levels.

All in all, deforestation is not a necessary by-product for supplying the world with sufficient food in the year 2050. However, one way or another, dietary change seems to be a prerequisite for sustainable development. Diets with reduced fractions of animal products would render high yields and further cropland expansion unnecessary, and indeed this study suggests that human diets are the strongest determinant of scenario feasibility. A vegan or vegetarian diet was associated with only half the cropland demand, grazing intensity and overall harvest volume of comparable meat-based human diets. From a sustainability point of view, it was shown that even in a zero-deforestation world, low-yielding agriculture such as organic farming is feasible when paired with plant-based diets. Animal advocates have hereby gained yet another resource confirming the positive environmental impacts of plant-based diets.