Researchers suggest that a pipeline to cut agricultural emissions could be combined with soil carbon sequestration to achieve net negative emissions in row crop agriculture.
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Contributed by Gregory P. Asner, September 30, 2013 (sent for review September 14, 2013)
Significance
Commodity gold prices increased substantially following the 2008 global financial crisis. Gold demand has fueled a massive increase in mining activity, some of which is centered in the Amazon basin. Western Amazonian forests of Peru have become an epicenter for mostly illegal gold mining, but the clandestine nature of mining activities has made monitoring and reporting of forest losses extremely challenging. We combined high-resolution satellite and aircraft-based imaging with field surveys to address this issue in one of the highest biodiversity regions on Earth: Madre de Dios, Peru. We found the gold mining extent and rates are far higher than previously reported, with critically important implications for the ecology and environmental policy of this unique tropical rainforest region.
Abstract
Gold mining has rapidly increased in western Amazonia, but the rates and ecological impacts of mining remain poorly known and potentially underestimated. We combined field surveys, airborne mapping, and high-resolution satellite imaging to assess road- and river-based gold mining in the Madre de Dios region of the Peruvian Amazon from 1999 to 2012. In this period, the geographic extent of gold mining increased 400%. The average annual rate of forest loss as a result of gold mining tripled in 2008 following the global economic recession, closely associated with increased gold prices. Small clandestine operations now comprise more than half of all gold mining activities throughout the region. These rates of gold mining are far higher than previous estimates that were based on traditional satellite mapping techniques. Our results prove that gold mining is growing more rapidly than previously thought, and that high-resolution monitoring approaches are required to accurately quantify human impacts on tropical forests.
Footnotes
- ↵1To whom correspondence should be addressed. E-mail: gpa{at}stanford.edu.
Author contributions: G.P.A., W.L., and R.T. designed research; G.P.A. and R.T. performed research; G.P.A. and W.L. contributed new reagents/analytic tools; G.P.A., R.T., and E.R.L. analyzed data; and G.P.A. wrote the paper.
The authors declare no conflict of interest.
This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1318271110/-/DCSupplemental.
Freely available online through the PNAS open access option.
Gold mining in the Amazon
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- Sustainability Science
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