A worldwide growth in the price of gold has accelerated the pace of deforestation in some of the most pristine parts of the Peruvian Amazon, where miners are cutting down trees in order to extract the valuable natural resource.
From 2003 to 2009, found a new study, the rate of deforestation in two gold-mining areas increased six-fold alongside record-setting leaps in the international price of gold. During one two-year period, as gold prices climbed steadily, forests disappeared at a rate of 4.5 American football fields a day from one of the two sites.
Alongside the accelerating paces of both mining and deforestation, the study found, there has also been an exponential rise in the use of mercury, which helps miners extract gold from the Earth. As a result, larger quantities of the toxic metal are ending up in the atmosphere and in Amazonian waterways and fish.
Together, the findings point to gold mining as an overlooked source of deforestation and environmental contamination in the Amazon, said lead author Jennifer Swenson, a landscape ecologist at Duke University in Durham, N.C. Until now, researchers have focused mostly on forces like agriculture, oil, logging and road construction.
"It's another blow that was not really anticipated," said Swenson, who added that the situation is particularly complex because Peruvian miners are among the poorest members of society. That makes it hard to recommend that people take measures like boycotting gold, which is unlikely to happen anyway.
"It's not like a big, bad company is doing this," she said. "It's a bunch of really impoverished people that don't have alternatives. What are they going to do for economic gain? There's not necessarily really a good solution. There's not an easy answer."
To see how artisanal mining might be influencing deforestation in the Amazon, Swenson and colleagues looked at satellite images of two gold-mining sites in Madre de Dios, Peru, dating back to 2003. Before that year, the area was a pristine swath of forest.
But over the next six years, from 2003 to 2009, the images showed a loss of more than 6,600 hectares (16,000 acres) to make way for gold mining activity. That was more than was cut down over the same period to make way for settlements in the area. And the trend paralleled a meteoric rise in the price of gold, the researchers report today in the journal PLoS One.
Over the course of the study, gold increased in value by about 18 percent each year, from a price of $300 per ounce in 2003 to $1,100 per ounce in 2010. This week, gold topped $1,500 per ounce, setting records for both the cost itself and the speed at which the price is going up. Since the end of her study period, Swenson said, the annual rate of increase has risen to 29 percent.
Even though gold fetches such high prices, the people who pull it from the Earth are among the poorest of the poor, said William Pan, an expert in global environmental health at the Johns Hopkins School of Public Health in Baltimore. And their jobs are not easy.
Artisanal miners face high risks of malaria, leishmaniasis and other diseases, while working 12-hour shifts for six days at a time. A typical yield is just one gram (0.04 ounces) for every 24 hours of work. And groups of four miners split just 10 percent of the cost of whatever they find.
Meanwhile, gold miners are exposed to large doses of mercury, which binds to gold in the soil, creating hard chunks that are easier to extract. Whatever mercury doesn't get bound up ends up polluting the water. And miners use blowtorches to burn off the bits of mercury that do find gold, infecting both the air and themselves.
There is no limit in Peru to imports of mercury. And the new study found an even stronger link between gold prices and mercury imports into Peru than between gold prices and deforestation. Everyone who lives near these gold mines, Pan said, knows that the fish there are not safe to eat.
Still, the profits are alluring enough to drive miners to dredge ever-larger swathes of Earth in search of gold in the soil. And the effect likely stretches far beyond the limits of the new study.
"This clearly shows that demand for gold and gold pricing might be another driver -- and a major driver -- of deforestation," Pan said.
"They're just capturing a bit of what's going on. It's really an underestimate."