Sitting on the back of a decrepit motorcycle taking me to a research site on the Congo River, I’m not sure I’ll live long enough to write anything. I had flown to the Congo for the rare opportunity to write about its rainforest, the world’s largest after the Amazon.
But as the motorcycle hurtles through the Congolese countryside, I must cling with bronco-rider strength to the cycle’s cargo rack as we spin through the loose dirt of a narrow footpath. Ahead a barefoot farmer, balancing a machete on her head, turns towards us. She leans back just in time to make room as my driver zips past. Unbloodied, we resume our pell-mell chase after a convoy of four other motorcycles ferrying the Belgian geographer Wannes Hubau and his team.
Hubau has been doing a painstaking forest census, a tally of the amount of carbon stored in a forest and one of the chief ways scientists investigate the health of the world’s jungles. Such studies have lead some scientists to conclude that tropical forests, which act like a giant carbon sink, have prevented the planet from warming too fast.
My trip has been in the works for months, one of several I’ve made in the last two years exploring the relationship between tropical forests and climate change. The Congolese rainforest is not much visited by scientists. Most of it lies within the Democratic Republic of Congo, which is perennially wracked with political turmoil and is run by a government infected with corruption. Those are the major reasons why most rural roads are rutted dirt and bridges at river crossings are often out. The Congo rainforest is also distant from significant research centers. Even the famously remote Amazon hosts a world-class jungle research institute in Manaus, a city of 2 million people in its center.
My heart is beating almost normally again a few minutes later, when we catch up with the others, where they’ve stopped at a broadening of the path. They’re sorting tape measures, bundles of numbered metal tree tags and food for lunch. As soon as our motorcycle’s engine goes quiet, a cloud of black flies as big and soft as over-cooked lentils forms around my head. The bugs climb into my nose and ears, tickling me — and not in a friendly way.
One-hundred feet above us a thick canopy of broadleaf trees I’ve never seen before blocks any shafts of sunlight from reaching the ground. The heavy vegetation bans every breeze, intensifying the day’s spiraling heat and raising a heavy sweat on the back of my neck and under the brim of my hat. “A vacation in paradise” said Hubau from inside his own swarm. This is my welcome to his survey site.
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For nearly 20 years I’ve reported around the world on climate science. Once, I hitched a ride on a LC-130 “Hercules” prop plane to the top of the Greenland Ice sheet. After two years of false starts and painstaking labor, a European team had just drilled all the way to bedrock, three kilometers below. They hoisted up a cloudy, thigh-thick cylinder of ice, the oldest ice ever obtained in the Northern Hemisphere. Spherical voids inside contained samples of air from before the ice age. Then, on a plane of unbroken whiteness, under a shower of powdery snow, the scientists feasted on gourmet cheeses, cured ham and caviar, and raised glasses of lab-grade alcohol.
Another time I watched the scientist Lonnie Thompson check the faltering health of the world largest tropical glacier, the Quelccaya Ice Cap, 5,500 meters above sea level in the Andes. In two dozen ascents since 1974, Thompson has documented the glacier’s terminal decline under increasingly inhospitable conditions. He forecasts that the entire glacier, big enough to cover Manhattan up to the 50th floor, will be gone well before the end of the century.
Thompson wheezed like a broken accordion on the final ascent to the summit. Air at that altitude contains half as much oxygen as at sea level. I struggled clumsily behind. That night, before collapsing in exhaustion, I recorded an audio diary in my tent “I’ve never been so miserable in my life,” I mumbled.
I’ve gotten sea sick in the Arctic and the Antarctic Ocean. I’ve yanked leeches off my ankles in Madagascar. I’ve waited out a stomach bug in a hotel in Peru. But until I joined Hubau in the Congo jungle, I’d never experienced such a combination of bodily discomfort, physical danger and potentially consequential scientific research.
An affiliation of British and Belgian researchers that’s been studying trees in about a dozen plots — each the size of two American football fields — dispatched Hubau to the Congo. They had sent other scientists to the same site twice before, in 2012 and 2014. Each time, the field workers followed the same painstaking protocol: they measured the girth of every tree in the plot — usually about 100 individuals--and tracked which ones died and whether new “recruits,” had appeared. The researchers are seeking to understand how the forest will respond to the conditions it will experience in the coming decades.
It’s an important question for researchers who study the earth’s climate. Of the 36 billion tons of the heat-trapping carbon dioxide gas that human activity creates each year, only half of it goes into the atmosphere. The rest is evenly split. Half dissolves into the ocean while the other half —converted into carbon compounds such as cellulose and sugars — is absorbed by land-based vegetation, including tropical forests. Rainforests hold enough carbon locked in wood and soil to increase the concentration of CO2 in the atmosphere by half. Many scientists fear that warmer, and possibly drier, conditions in the future could degrade these forests and unleash this carbon, accelerating climate change. Since the previous census, an El Niño had struck, substantially warming the forest. Nature had given the researchers an unusual chance to check out the forest response to conditions they think might mimic those of the decades ahead.
Before we’d driven to the site, Hubau had shared a concern with me. From the maps he’d pored over, he worried that the study plots were too close to areas that had been logged for farming, possibly invalidating the results. But his worries evaporated once we arrived. “This is deeper into the forest than I thought,” he said approvingly. “It’s a pretty good forest.”
He walked over to a tree as broad as a phone pole and inspected a tag nailed to its trunk. He located the tree’s record on a data sheet. One assistant wrapped a tape measure around the tree and called the circumference out to Hubau. A second assistant painted a blue line where the measurement had been made.
“I think we have a system going,” said Hubau. The results that system creates may hold some answers to the future and utility of the Congo forest in a warming world.
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Daniel Grossman is a three-time winner of the AAAS Kavli Science Journalism Award. His reporting in the Congo was supported by the Pulitzer Center on Crisis Reporting. His latest reporting project is in Indonesia.
[Homepage photo credit: Daniel Grossman]