Ancient human disturbances may skew understanding of Amazon and its impact (Update)
January 10, 2017
Pre-European human populations of the Amazon Basin may have affected our contemporary understanding of the forest's structure and composition, and thus our calculations of its impact on carbon dioxide remediation, according to new findings published in the Proceedings of the National Academy of Sciences.
Researchers at Florida Institute of Technology, the University of Amsterdam, the University of Miami, and Wake Forest University report that forest plots in the Amazon Basin are primarily located in areas with a high probability of ancient human activity.
Our current understanding of the Amazon rainforest comes from a small network of fewer than 1,000 pieces of forest land spread out across the nearly 2.3-million-square-mile basin. Scientists have inventoried biodiversity and have been measuring how much and how fast Amazonian forests can absorb carbon dioxide from the atmosphere with the assumption that the plots were in their most pure state.
But if these plots are likely to have been disturbed by ancient people, which is what the new study implies, how much and how fast untouched Amazon forest can absorb carbon dioxide may not be completely accurate. Given the very long lifespan of some Amazonian trees, with some living for more than 400 years, many forest plot sites may still be recovering from past human disturbances. If so, these sites are growing faster than mature forests and may exaggerate the amount of carbon that can be absorbed by the forest as a whole.
"We have sampled less than 0.0005 percent of the Amazon Basin, and all that we know about its ecology comes from this limited forest plot network," said Crystal McMichael, the lead author and professor at the University of Amsterdam and a former research scientist at Florida Tech. "We may need to reevaluate what we know about biodiversity and carbon budgets given that many of these forests may still be recovering from past disturbance."
There’s no one-size-fits-all solution to climate change
From the Field Museum
New study shows where carbon finance should — and shouldn’t — drive conservation efforts
The world’s forests are crucial to slowing climate change, but they’re often destroyed to make room for farms, mines, and other economic ventures. One possible solution to deforestation is carbon finance: giving companies and countries monetary incentives to reduce their climate change-causing carbon emissions from deforestation. But carbon finance isn’t in place on the large scale yet, and it’s unclear how effective it might be. A new study suggests that potential success for carbon finance varies widely–it can work under the right conditions, but it’s not a one-size-fits-all solution.
“Forests are one of the most important tools available to humanity for mitigating global climate change. This study tells us what the viable solutions might be in different areas,” explains the study’s lead author Ashwin Ravikumar, an environmental social scientist at The Field Museum in Chicago. “No one solution will work everywhere–we need to tailor solutions and funding streams to individual situations.”
In a paper published in Environmental Research Letters, Ravikumar, along with researchers from the Department of Forest Services in Finland and the Center for International Forestry Research in Peru, explores the potential benefits of carbon finance in various landscapes around the world. The team conducted a series of workshops in Indonesia, Peru, Mexico, and Tanzania, asking local farmers, politicians, NGO officers, and businesspeople to come up with their best guesses as to how business and farming might affect land use in the coming decades. The scientists then compared these hypothetical land uses to the current ones and determined how much money could be earned by countries working to conserve forests and reduce their carbon output. The results were hugely varied.
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