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In Congo, a carbon sink like no other risks being carved up for oil

Study co-author Corneille Ewango.

Study co-author Corneille Ewango of the University of Kisangani, DRC, takes notes in a peat swamp forest along the Ikelemba River in the DRC. Image courtesy of Bart Crezee/University of Leeds.

  • New research has revealed that the peatlands of the Congo Basin are 15% larger than originally thought.
  • This area of swampy forest holds an estimated 29 billion metric tons of carbon, which is the amount emitted globally through the burning of fossil fuels in three years.
  • Beginning July 28, the government of the Democratic Republic of Congo, where two-thirds of these peatlands lie, will auction off the rights to explore for oil in 27 blocks across the country.
  • Scientists and conservationists have criticized the move, which the government says is necessary to fund its operations. Opponents say the blocks overlap with parts of the peatlands, mature rainforest, protected areas, and a UNESCO World Heritage site.

The world’s largest bank of the partially decomposed plant matter known as peat in the tropics is even more extensive than initially thought, according to a new study.

The peatlands of the Congo Basin cover some 167,600 square kilometers (64,710 square miles) in the Republic of Congo and the Democratic Republic of Congo (DRC), a team of scientists reported July 21 in the journal Nature Geosciences. The new maps confirm that the area, sometimes called the Cuvette Centrale, is about the size of England and Wales combined, which is 15% bigger than the estimates from the original mapping of the area.

“It’s a massive area. That’s for sure,” Bart Crezee, the study’s lead author and a postgraduate researcher at the University of Leeds in the U.K., told Mongabay.

Part of the research team traveling in a dugout canoe on the Ruki River in the DRC. Image courtesy of Bart Crezee/University of Leeds.

Little was known about the location, size and carbon contents of these peatlands deep in the world’s second-largest rainforest before a team of scientists shared their maps based on satellite imagery and extensive on-site fieldwork in a 2017 paper in the journal Nature. Peat forms when the water that swamps the mix of soil and plant matter on the floor of this forest chokes off oxygen to bacteria and fungi, arresting the normal decomposition that would occur in a less soggy rainforest. As a result, much of the carbon in these bits of plants gets locked away in the ground instead of being emitted into the air. It turns out the Congo Basin’s peatlands hold a mind-boggling amount of carbon, on the order of the global emissions produced by burning fossil fuels in three years.

Those findings demonstrate that these peatlands are a powerful tool in combatting climate change: Left undisturbed, that carbon will remain locked away and out of the atmosphere where it could add to global warming — unless something shifts the balance or triggers the release of carbon. Widespread logging and industrial agriculture have levied a hefty toll on the peatlands of Southeast Asia. Cleared and drained to support crops such as oil palm, they’ve become a significant source of carbon emissions instead of a reliable storehouse.

Such disruptions could come from farming or timber extraction, or, from what appears to be the most pressing threat, exploration for oil from deep beneath the ecosystem. In April, the government of the DRC, which is home to two-thirds of the Congo’s peatlands, approved the auction of the rights to explore for oil in several blocks of land, including parts of the peatlands, raising serious concerns in the scientific and conservation communities about their future.

Researchers measure the depth of a peat core that they brought up to the surface. Image courtesy of Bart Crezee/University of Leeds.

Refreshing the data

Building on that 2017 Nature paper that focused on field measurements from the Republic of Congo, Crezee and his colleagues extended their work into the DRC. They spent weeks at a time in these swampy forests, coring out samples of the earth to confirm the presence of peat.

Their surveys revealed that the peatlands were substantially larger than the original estimate of 145,529 km2 (56,189 mi2). The team also learned that, by and large, much of the peat in the DRC had formed by a different set of processes. In the Republic of Congo, rainwater pooling in basins sitting between the relatively high banks of streams and rivers has led to peat formation over the past 10,000 years or more. But in the DRC, overflowing rivers spilling over their banks concentrated in small valleys, providing the necessary conditions for peat formation.

The scientists also found peat as thick as 6 meters (nearly 20 feet) in the DRC, Crezee said. It’s from the thickness of the peat, calculated to be an average of around 1.7 m (5.5 ft) across the entire basin, that the researchers were able to estimate the amount of carbon. The 2017 paper had pegged the carbon value at around 30 billion metric tons. But because that estimate was based on a handful of randomly chosen values for the thickness of the peat, there existed the possibility, in theory at least, that it could have contained as little as 6 billion metric tons. With this new study, the researchers’ expanded fieldwork allowed them to zero in on a more precise value, which turned out to be quite close to the original estimate. The new study reports that around 29 billion metric tons of carbon are held in the peatlands.

The team’s analysis also confirms that the Cuvette Centrale is among the most carbon-dense environments on the planet, with a density nearly twice that of the peatlands found in the Peruvian Amazon. Across both Congos, it accounts for more than one-quarter of all carbon in the world’s tropical peat reserves.

The Congo Basin’s peatlands also remain relatively intact. Scientists and conservationists say it should stay that way, both to minimize the release of carbon into the atmosphere and limit the effects of climate change, and also to preserve a unique ecosystem that supports wildlife and human communities.

The looming oil auction beginning July 28, however, presents a clear danger to the delicate balance in the peatlands.

Stilt houses in a fishing camp along the Ikelemba River in the DRC, which has overflowed its banks at the end of the wet season. Image courtesy of Bart Crezee/University of Leeds.
A map shows the overlap of the oil concessions for tender with protected areas in the DRC. Image courtesy of the CongoPeat project/University of Leeds.

Oil — a pathway to development?

Leaders in the DRC have long set their sights on increasing the country’s oil production. In May 2022, Didier Budimbu Ntubuanga, the DRC’s minister of hydrocarbons, announced that his office would hold its auction for 16 blocks, including several in the Cuvette Centrale, on July 28 and 29. On July 19, the ministry tweeted that the number of blocks on offer had increased to 30 — 27 for oil and three for natural gas.

Crezee and his colleagues at CongoPeat, a group of researchers based in the U.K., the Republic of Congo and the DRC formed to study the Cuvette Centrale, used the map from this new study and found that three of the oil blocks hold some 10,000 km2 (about 3,900 mi2) of peatland. That area contains an estimated 1.67 billion metric tons of carbon that’s being kept out of the atmosphere.

They also calculated that, more broadly, 112,000 km2 (43,000 mi2) of tropical rainforest lie within the borders of the blocks on offer. And, despite Budimbu’s initial insistence to the contrary, Greenpeace found that at least nine and perhaps as many as 12 blocks overlap with parts of protected areas in the DRC.

The hydrocarbons ministry later told Greenpeace in a written statement that the government had decided it could decommission “protected areas abounding in natural resources with high economic value.”

Simon Lewis, the co-lead author of the initial study to map the peatlands and the senior author of this latest paper led by Crezee, recently wrote an op-ed in The New York Times calling for the cancelation of the auction. He noted that the companies making winning bids for exploration are gambling on as-yet-unproven reserves in this part of the DRC, and that the costly process of extracting oil from such remote locations wouldn’t be “economically viable.”

“Yet, even if the initial survey revealed no commercial-scale oil deposits, the rainforests’ biodiversity value would still be destroyed,” wrote Lewis, a botanist and a professor at the University of Leeds. The vibrant forest hosts untold plant species and rare and threatened wildlife such as lowland gorillas, chimpanzees and forest elephants.

A peat swamp forest along the Ikelemba River in the DRC during the dry season. Image courtesy of Bart Crezee/University of Leeds.

France’s TotalEnergies and DIGOil, a South Africa-based company, both told Mongabay they would not participate in this tender, though they did not comment on why they had made that decision. An industry source said that U.S.-based Chevron has also declined to take part.

Even minor incursions into the peat-containing forest could lead to a “snowball effect” in which impacts could grow to be far more widespread, Crezee said. Roads built to bring in the equipment could alter the movement of water that maintains the peatlands. Loggers searching for valuable timber species and hunters looking for new quarry could further disrupt the ecosystem.

If the companies were to find enough oil to make production worth the cost and effort, Lewis pointed out the problems exploitation has caused in rainforests elsewhere. He said that spills could spell disaster for fish, wildlife and people, and the peatlands’ soggy environment would complicate any cleanup process. Lewis added that toxic wastewater is also a byproduct of extracting oil from the ground, noting the documented effects on communities in the Peruvian Amazon.

“In one study, 98.6 percent of children living in an oil production zone exceeded the safe limits for the cancer-causing heavy metal cadmium in their blood,” he wrote.

The potential damage that oil exploration and exploitation could cause has led Greenpeace to condemn the move by the DRC government to hold the auctions.

“The auctioning of new oil blocks anywhere is wrong and undermines communities’ right to a healthy environment,” Irene Wabiwa Betoko, Greenpeace Africa’s international project leader for the Congo Basin forest, said in an April 2022 statement. “The plan for big oil companies to trash Congo’s most sensitive ecosystems is a historic error that must be scrapped immediately.”

Study co-author Corneille Ewango of the University of Kisangani, DRC, studies a peat swamp forest dominated by large Raphia laurentii palm trees. Image courtesy of Bart Crezee/University of Leeds.

Leaders in the DRC say the country must use its natural resource wealth to end the widespread poverty that its citizens face. According to the World Bank, nearly three-quarters of the country’s citizens subsisted on less than $1.90 a day in 2018.

The DRC’s annual budget isn’t more than $10 billion. By contrast, Budimbu said in May that early data suggest 16 billion barrels of oil are thought to lie in the original 16 oil blocks, worth $650 billion at the then-current price of $107 a barrel, according to Bloomberg. Budimbu acknowledged that further exploration was necessary to confirm the presence of “economically profitable hydrocarbon deposits.” Since then, oil prices have since fallen slightly. Observers have also raised concerns about the future of fossil fuels as the cost of renewable energy drops, leading to questions about whether the years of upfront investments in exploration and infrastructure needed to bring oil production online will pay off in the long run.

“Our country must move forward — we must find the money,” Budimbu told The Washington Post. He added, “[W]e cannot sacrifice the economy for the sake of the environment.”

Ève Bazaiba Masudi, the DRC’s environment minister, echoed similar sentiments in comments to Mongabay in 2021. “The value of conservation as well as the value of exploitation needs to be carefully considered,” Bazaiba said.

Still, one of the most significant agreements to come out of the United Nations climate conference last November, held in Glasgow, Scotland, was a pledge by wealthy countries through a program known as the Central African Forest Initiative (CAFI) that would provide $500 million to the DRC to maintain its standing forests to benefit the global climate. Now, the impending auction calls into question the country’s leaders’ commitments to the meaningful protection of forests, Wabiwa said in another statement.

“The mouth that says all the right things about the climate and biodiversity crises works separately from the hand that signs the contracts that make them worse,” she said.

For its part, CAFI told Bloomberg that the agreement called for “a comprehensive analysis of the extent to which mining, oil and gas titles overlap with, or impact on protected areas, high value forests and peatlands.”

With the auction set to begin, one of the first casualties could be this pledge. “[I]f the oil is developed, the credibility of this flagship plan for protecting the world’s second-largest rainforest will lie in tatters,” Lewis wrote in his op-ed.

The top 50 centimeters (20 inches) of a peat core collected by the research team. Image courtesy of Bart Crezee/University of Leeds.

Strategies for protection

Establishing parks and reserves to protect sensitive ecosystems like the Congo Basin peatlands may seem like a potential solution. Today, only 8% of the Cuvette Centrale lies in protected areas. But authorities’ willingness to redraw the lines in ways that would allow unfettered access to valuable resources indicate that even robust efforts to keep out industrial development and extraction may not be enough.

Crezee pointed to a block up for lease in the auction that includes parts of eastern DRC’s Virunga National Park, home to the endangered mountain gorilla (Gorilla beringei beringei). In addition to being the continent’s oldest national park, it’s also listed as a UNESCO World Heritage Site, making it “double-protected, in a sense,” Crezee said.

Instead of — or perhaps in addition to — creating protected areas in the peatlands, Crezee said the answer may lie with the people who have lived in the region for generations. They make use of the resources in these forests, from harvesting trees for construction to collecting medicinal plants to fishing in the waterways. And yet, by many measures, the peatland forests show few signs of destructive human impacts.

“My personal opinion is that a major solution lies in giving these local communities legal rights to their lands,” Crezee said. “They have a vested interest in protecting their land.”

The auction of oil leases beginning on July 28 increases the urgency of these efforts, as well as research to understand the complex dynamics that maintain the stability of the peat in the Cuvette Centrale.

“It feels very irresponsible to start drilling for oil when you don’t even know or haven’t assessed what kind of impact it would have on such a fragile ecosystem,” Crezee said.

Banner image: Study co-author Corneille Ewango of the University of Kisangani, DRC, takes notes in a peat swamp forest along the Ikelemba River in the DRC. Image courtesy of Bart Crezee/University of Leeds.

John Cannon is a staff features writer with Mongabay. Find him on Twitter: @johnccannon


Crezee, B., Dargie, G. C., Ewango, C. E., Mitchard, E. T., Emba B., O., Kanyama T., J., … Lewis, S. L. (2022). Mapping peat thickness and carbon stocks of the central Congo Basin using field data. Nature Geoscience. doi:10.1038/s41561-022-00966-7

Dargie, G. C., Lewis, S. L., Lawson, I. T., Mitchard, E. T., Page, S. E., Bocko, Y. E., & Ifo, S. A. (2017). Age, extent and carbon storage of the central Congo Basin peatland complex. Nature542(7639), 86-90. doi:10.1038/nature21048

Related reading: Review the top takeaways from this reporter’s recent four-part series on this issue, “The Congo Basin peatlands,” and link to each of the parts:

The past, present and future of the Congo peatlands: 10 takeaways from our series

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