Environment

Inside the search for Africa’s carbon time bomb

Journey into the wilds of the Congo rain forest with scientists trying to locate a shockingly large peatland – so that they can help to preserve it.Wednesday, 2 October 2019

By Daniel Grossman
Two men paddle a canoe o​n the Congo River.
This story was produced in partnership with the Pulitzer Centre.

It had been three busy days since Greta Dargie had returned to Mbandaka, a city on the western border of the Democratic Republic of the Congo. She moved through the local outdoor market in search of a few more pieces of equipment, trailed by a local college student holding a calculator and two porters dragging a wooden cart. It was a treasure hunt.

Doling out fistfuls of Congolese 1000 franc notes from a backpack heavy with bricks of mille moko bills, they’d found cases of squat sardine tins, a sack of rice, a dozen plastic chairs, bales of toilet paper, jugs of gasoline, a bundle of machetes—several tons of food, fuel, and camping gear. There were a few more research and travel permits to get stamped, but they were nearly ready. Soon, they’d motor up the Ruki River, a tributary of the Congo River, in a pair of dugout canoes, in search of another sort of treasure.

“We’re pretty much done,” said Dargie, an environmental scientist at the University of Leeds, arriving back to the peace of Auberge Emma. The walled hotel was out beyond the clouds of dust, incessant honking of horns, and clacking of wooden blocks made by street urchins advertising their shoe shine services.

“Do you think it’s going to fit?” said Bart Crezee, a PhD student from Leeds, staring at the small mountain of cargo they’d assembled in the hotel’s courtyard.

“I don’t know,” said Dargie. “Depends on how long the boat is.”

Just one thing was missing. Creeze and Nick Girkin, a scientist from the University of Nottingham, each needed a pint of acid for preserving samples they’d collect on their expedition: Nitric acid for Bart, sulfuric acid for Nick. They hadn’t dared bring the corrosive chemicals on the flights from England. They’d figured a drug store in Mbandaka (bahn-DOCK-ah) would stock the acids—both are strong disinfectants. But no luck. They were on a strict timetable, with a limited budget, but they couldn’t leave without the chemicals.

A search for answers

January 11, 2017 is a good a date to explain why Dargie and her colleagues ended up in Central Africa, where the Congo River crosses the Equator. The results of Dargie’s PhD thesis were published on that day. She’d coauthored the paper—now a minor classic in her field—with senior colleagues. In a series of arduous expeditions into some of the Congo Basin’s most remote regions, Dargie and her graduate advisor, Simon Lewis, had discovered a huge deposit of peat—soil consisting of undecayed vegetation—in a flat region called the Cuvette Centrale, in the heart of the Congo rain forest. The previously undocumented peatland flanked the Congo River, its tributaries, and the hundreds of valleys they drain. It was the size of England, what Dargie believes is “the largest tropical peatland complex in the world.”

The paper raised more questions than it answered, however, and Dargie and her team were back in the DRC to investigate them. Most important was how safe the newly discovered peat deposits were from some future disturbance of human or natural origin. And what were the planetary implications if the peatlands were damaged.

Pound for pound, peat is an incredibly carbon-rich soil. Over thousands of years, peatlands can build up into deposits tens of feet thick. Peatlands cover just 3 percent of the earth, but stockpile twice as much carbon as all of the world’s trees and one-fifth of all the carbon stored in soils. If just a third of this peatland burned, the amount of CO2 in the air would double. Scientists say a change like that in the composition of the atmosphere could warm the planet about 2.8 degrees centigrade, or 5 degrees Fahrenheit – a catastrophic rise.

Fortunately, these carbon repositories, mostly in temperate and polar regions, seem safe for now. Locals and some scientists had known about the flooded forests in the Cuvette Centrale, but hardly anyone thought the soil was peat. Dargie’s discovery astounded and rattled many scientists.

“ … We thought the number was too high and we had to go back and check it,” recalled Dargie. There was no mistake. Her results showed that the deposit contained 33 billion U.S. tons of carbon, as much as in all the trees in the entire Congo rain forest, an area 13 times bigger.

“It’s a whacking big stock of carbon,” says William Laurence, an ecology professor and tropical forest expert at James Cook University in Australia. “Everybody was surprised,” he says.

But it worried them, too. If those peatlands caught fire it could let off three times more carbon than the annual global output of all human activities. It would also destroy an efficient source of carbon storage.

The location of the expedition in the DRC.

Peatland fire danger

Since 1990, about 250,000 square miles of peatland in Indonesia—an area about the size of France—has been intentionally deforested, drained and planted with oil palm. The results have been disastrous. In 1997, an especially dry year, fires raged on 12 percent of the country’s peatlands, primarily parts that had been converted to agricultural use. The conflagration emitted about 4 billion tons of carbon dioxide, approaching what the entire U.S. releases each year.

Another inferno engulfed Indonesia in 2015. The country’s president, Joko Widodo, has made preventing wildfires, now a perennial problem, a national priority. But widespread blazes in Sumatra and Borneo in the last several weeks suggest the battle might be harder than he expected.

Tropical peatlands are a concern to scientists. With abundant sunlight, heavy rainfall and year-round high temperatures, they are inviting places for industrial agricultural development.

The Congo jungle is where Elaeis guineensis, the most commonly farmed oil palm variety, evolved, so clearly the tree fares well there. Some scientists fear that this region in particular could be targeted for widespread clearing and replacement with industrial oil palm. Already, investors have planted some oil palm plantations in Congolese peatlands.

Up the river to the bog

Crezee took on the job of investigating the swamp’s plumbing. In parts of the Cuvette Centrale that Dargie and Lewis never studied, including along the Ruki, nobody knows whether the water saturating the ground originates as rainfall or seeps from the rivers that run through the region. If it’s rain that then flows into rivers it could be feasible for landowners to drain it with canals, which would dry the soil. That would be good for installing palm oil plantations. But it could also make the peatlands as flammable as Indonesia’s combustible plantations, with implications for the entire planet.

Crezee’s main job in the peatlands would be to take water samples to determine their origins. Adding a few drops of nitric acid before capping each bottle killed microbes and halted chemical changes, putting the samples in suspended animation until he could study them back in Leeds.

Crezee first heard about the Cuvette Centrale’s peat in the newspaper. It fascinated him. A couple weeks later he noticed that Lewis had posted a job for somebody to extend the research Dargie had started. He was an aspiring journalist who wanted to help slow climate change. He applied immediately and went to work for Lewis.

“You can change your light bulbs,” Crezee says, “but helping to protect 30 billion tons of carbon has a bigger impact.”

At the last minute Girkin and Crezee located their acids. A technician at a health clinic told them he knew who had acid at Mbandaka’s local hospital, and offered to go get it. Removing a white lab coat and a pair of rubber gloves, he’d driven off on the back of a motorcycle taxi. Hours later he returned, hugging two small bottles to his chest. He packed them in a bag, protected by a nest of fashionable hair attachments.

The renowned Congolese botanist Corneille Ewango, a professor at the University of Kisangani and a National Geographic explorer, flew in from the capital, Kinshasa, and boarded one of the boats just in time to join the trip. The Congo forests has hundreds of species of trees, many of which look practically identical. Ewango knew how to tell them apart by the colour of the sap and the smell of the wood.

“Now we begin exploring,” he yelled gleefully when the outboards growled to life and we shoved off from Mbandaka’s bustling port.

Six hours up the Ruki, the team’s dugouts pulled up to a rickety dock in the village of Mpeka, which consisted of just a few houses on stilts.

On their first day there, the crew met local officials and the owner of the swamp site where they’d chosen to work. In several meetings that attracted the curiosity of what appeared to be most of Mpeka’s tiny population, Ewango explained in Lingala—one of many languages spoken in the DRC—that the scientists only wanted a few dozen plastic bags of soil. They’d dig vertical samples with a steel auger, the first at the surface, then others all the way to the bottom layer of peat. They might have to go down only a few inches, but the peat could extend 20 feet below the surface. They’d continue digging such cores at intervals along a straight line 6 miles long.

Ewango said the distribution, depth and plumbing of peat in Mpeka might differ from that in areas already studied—and places they planned to sample in subsequent research stops. He added that the data they’d collect would help scientists refine maps of the peatlands, total up the area’s carbon content and predict how waterlogged soil would respond to climate change and land-use changes.

He also told them that he and his crew were not prospectors exploring for oil or gold, that they were scientists, though not all of the villagers seemed convinced. Then he handed out several envelopes stuffed with cash gratuities of up to 50,000 francs (about £25).

“Peatlands cover just 3 percent of the earth, but stockpile twice as much carbon as all of the world’s trees and one-fifth of all the carbon stored in soils. If just a third of this peatland burned, the amount of CO2 in the air would double.”

Where's the peat?

Two days after landing at Mpeka, sweltering, we trudged single file between two opaque walls of palm fronds. My hands smarted from grabbing a branch bristling with sharp spines. Black ants somehow overran my belly, despite my best efforts to avoid them. Their bites burned. Small flies swarmed over my arms and neck, which began to itch. My rubber fisherman’s boots had filled with water.

“These places are the worst ecosystems,” muttered Dargie to no one in particular. It was her first day on this trip in the jungle, but she walked along describing her wish for “a piece of cake and a cup of tea,” at home in Scotland. Girkin said he’d be satisfied with just the tea.

Dargie squatted and stared at a laminated map she’d created by combining satellite photos and radar data. The forest was a mosaic of dark and light greens—pea green for palms, royal green for hardwood. She’d included the line of sampling points, perpendicular to the Ruki in yellow.

“You worried about peat?” asked Girkin. She nodded.

Hired villagers had slashed a mile-long path into the swamp. Every 270 yards Crezee had been plunging a thumb-thick stick he’d cut from a sappling broom-handle deep into the soggy ground. Each time it had come up coated in grey clay slime, with no hint of brown peat. If Dargie’s map was accurate, we should have started walking on peat hours earlier. She’d have to revise her methods for predicting the location of peat if we didn’t find some soon.

More pressing, the environmental group Greenpeace—which supports the project with in-kind logistical assistance—had invited a troop of journalists to see the research. A television crew had landed from Paris. Their boats would arrive in the late afternoon. And the next day they’d want to shoot footage of the team auguring up carbon-rich soil.

“What if we haven’t found any peat?” Dargie asked plaintively.

Crezee idly fingered the GPS navigation device that hung around his neck and stared at the ground.

“That’ll be Greenpeace’s problem,” Girkin snapped. “They brought the journalists before we found the peat.”

I’d also begun to worry. I knew that this expedition would continue for weeks after I flew home, and that this trip was only one of several planned. And after the field work was done they’d study their samples and measurements for months or years before publishing results. Still, I too hoped to see Dargie and her crew dig up at least a handful of peat we’d all come so far to find.

A muddy treasure

Brambles slowed our progress. The researchers had anticipated a forest of pineapple-palm-like raffia with identifiable trunks and fronds mainly overhead. A machete chop now and then, and the passage would be easy. But here, dense tangles of tough rattan canes took serious chopping. We crawled forward. No one had experienced such tough going in prior peatlands.

“It’s rare,” Crezee said, shrugging.

“Rare, but annoying,” Girkin said.

It was late, and the swamp quivered with staccato machete blows. Finally, we reached a clearing. We sat in a circle for a late lunch. Dargie passed chikwangue, a rubbery, bread-like cassava staple boiled and stored in big leaves, and cans of sardines.

After eating, Crezee shoved his stick into the ground. It came out coated with chocolate-colored paste. It was as thick as pudding, and grainy. That told us everything we needed to know. We were seated on a layer of peat. It was four feet thick.

“Thank god,” Dargie sighed.

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