Even with a growing global population, increased meat consumption and government rules mandating biofuels, researchers this week said that the amount of landed needed for agriculture will start to shrink.
Humanity has reached what Rockefeller University scientists, in a new report, call "peak farmland." In the next half-century, a geographical area more than twice the size of France -- or equivalent to 10 Iowas -- will return to its natural state from farmland, they predict.
The findings contradict other reports warning of a "soylent green" scenario, where an increasingly crowded planet tightens agricultural resources.
But the Rockefeller researchers say population growth has slowed considerably since cresting around 1970. Destruction of forests is on the decline, due in part to environmentalist activism, a slide in demand for wood products such as telephone poles and the rise of technologies such as e-publications replacing paper.
Even as humans become more affluent, meat consumption habits haven't kept pace, researchers found. Satisfying the world's carnivores means dedicating crop space for animal feed.
Most important, however, farmers are boosting their yields, making their existing fields more efficient. Improvements in fertilization methods, irrigation technologies, pest control strategies and weather forecasting mean that growers have been able to coax more out of a plot of land without having to expand the size of the space.
Without such trends, however, "unimaginable destruction of nature would have occurred," researchers said.
The projections are also at the mercy of several wild cards.
Regulations requiring more biofuels could eat up more agricultural land, they said. Farming innovations could hit a standstill. Better-fed humans could grow up bigger and taller, requiring more daily calories.
"Expecting that more and richer people will demand more from the land, cultivating wider fields, logging more forests, and pressing nature, comes naturally," researchers wrote.