Ticking 'carbon time bomb' has been unleashed in the Amazon rainforest by gold miners

Gold mining in Peru has moved into sensitive wetland areas and is releasing a lot of stored carbon. These wetlands are peatlands, waterlogged soils built from partly decayed plants that lock away carbon for centuries.

Peat loss turns a slow natural carbon vault into a fast source of emissions. That is why scientists are sounding the alarm about new mining scars in remote corners of the Amazon.

Peatlands, carbon, and mining

Peatlands hold an outsized share of the world’s soil carbon and help stabilize climate over long timescales. They cover a small slice of land area yet store a huge fraction of carbon underground.

Lead researcher J Ethan Householder is with the Wetland Department, Institute of Geography and Geoecology at Karlsruhe Institute of Technology in Germany (IFGG).

His team’s field work and satellite analyses focus on peat swamps in southeastern Peru.

The term carbon stocks refers to the amount of carbon stored in plants and soils. In peat, most of that carbon sits below the surface in thick, oxygen poor layers that decompose very slowly.

These peat swamps also support biodiversity, the variety of living species in an ecosystem. When mining drains or digs up peat, both the carbon bank and the living communities take a hit.

What the satellites saw

The study analyzed more than three decades of images from Landsat, a U.S. satellite program that produces consistent pictures of Earth’s surface each year.

That time series lets researchers pinpoint when forests were cleared and when bare mine pits appeared.

They mapped mining scars along rivers in Madre de Dios, a region in Peru that has seen a rapid spread of small operations. The scars are easy to spot because forest gives way to sand and water filled pits.

Massive carbon release from mining

In a new paper, the team reports that mining has removed more than 550 hectares of peatland, with over half of that loss happening in just the last two years.

They estimate that 0.2 to 0.7 million tons of carbon have already been released, and they identify 63 of 219 peatlands showing evidence of mining at their edges.

They also find that mining inside peat now accounts for 9 percent of all mining in the area and could reach 25 percent by 2027 if current trends hold.

The analysis flags more than 10,000 hectares of peat at immediate risk, with a potential release of 3.5 to 14.5 million tons of carbon if those areas are disturbed.

“The rapid proliferation of gold mining inside peatlands appears to be of such scope as to be an existential threat to the entire peatland complex,” wrote Householder. The numbers and the geographic pattern point in the same direction.

The team also tracked where mining is advancing. An outward front has been pushing into the alluvial plain at about 330 feet per year, and that front is reaching the peat rich margins where swamps are most common.

Why mining is pushing into peatlands

Rivers are the main highways in this part of the Amazon, so early mines hugged the banks.

As miners followed gold bearing sediments inland, access paths, machinery, and makeshift camps increased, lowering the barrier to work in wetter ground.

Peatlands sit on the outer edges of the river plain where water pools for most of the year.

Once miners arrive with pumps and hoses, it gets easier for others to follow, especially where law enforcement relies on boats and cannot easily reach new clearings.

Human-driven destruction

A long term remote sensing research record shows that mining has been a major driver of deforestation in southeastern Peru.

Many operations are small and informal, and the work is a source of income for thousands of families.

Processing often uses mercury, a toxic metal that binds to fine gold particles.

One river focused study documented elevated mercury in sediments and fish downstream of mining hubs and found that a large share of carnivorous fish exceeded health guidelines for mercury in tissue.

Communities that rely on river fish face real exposure risks. This adds a public health layer to the climate and ecosystem costs of tearing up peat.

How mining made this carbon bomb

The researchers combined annual vegetation change with a classifier that separates mining from other forest losses. That approach reduced false alarms from seasonal flooding or quick regrowth after storms.

They then overlaid those mine maps with peat maps to see where pits and ponds overlap organic soils. That allowed them to calculate both the area lost and the likely carbon released.

Peat stores carbon more densely than nearby upland forests. When miners dig pits, drain water, or burn cleared vegetation, oxygen speeds up decay and carbon escapes into the air.

Even small patches can have outsized impacts because a few feet of peat can hold as much carbon as a much larger area of non peat forest. That is why a few hundred hectares of loss matter.

What happens next

The results point to three priorities that do not require new technology.

Map the edges of active peatlands at high resolution, monitor hot spots in near real time, and keep heavy equipment out of places where peat depth is greatest.

Local voices and science can work together to steer enforcement and restoration budgets to the areas of highest risk.

Peat that stays wet and shaded keeps its carbon, and that is the simplest way to avoid adding more heat trapping gases to the air.

The study is published in Environmental Research Letters.

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