In all the grim environmental news around the turn of the millennium, few things were worse than the state of the Amazon, with at least 13,000 square kilometers (5,000 square miles) felled each year. In 2006 major purchasers of soy products agreed not to buy soy from newly deforested land. That this contributed to saving a lot of forest was already acknowledged, but a new paper in PLOS ONE indicates the difference it made was much larger than previously realized, pointing the way for future efforts to save the world's most valuable ecosystems.
The Amazon is easily the world's largest rainforest and absolutely essential to the health of the planet. It faces threats from many directions, including cattle ranching, mining and major dams. However, in the early '00s, one of the biggest problems was the clearing of rainforest in Mato Grosso, Brazil to make space for soy bean plantations. Some 85 percent of the Brazilian rainforest cleared for soy was in Mato Grosso province. This one state accounted for up to half the annual clearance in the Amazon as a whole.
Facing pressure from consumers, in 2006 the big soy bean companies agreed not to buy product grown on land that had been rainforest as of July of that year. This promise was known as the "soy moratorium".
Deforestation was trending down across the Amazon at the time and is now around a fifth of what it was at its peak. As encouraging as this is, confusion about the causes of the decrease make it hard to know how stable the situation is, and whether it can be replicated in other threatened regions.
Dr Jude Kastens of the University of Kansas measured the effect using satellite images of the region, confirmed with ground measurements, creating a time series of the area from 2001 to 2014. Each pixel can be identified as forest, cropland or pasture. After the moratorium came into effect the area of forest converted to soy production roughly halved each year. To reflect the fact they could no longer simply go and seize more, farmers started treating land as more valuable, growing two crops a year, where previously one had been more common.
Overall, forest destruction in Mato Grosso reduced after the ban by a factor of 5.7 – more than 80 percent. Where lower resolution studies suggested most of the fall in forest clearing occurred before the moratorium, Kastens' work indicates the timing was much more closely tied to the ban, and probably caused by it.
Recent political upheavals in Brazil have raised concerns the Amazon may be under renewed threats, but Kastens' work raises hopes that international consumer pressure can limit the damage.
Why have this when you can chop it down and grow soy beans on the land instead. Luciano Queiroz/Shutterstock