The Killing Lakes

Lake Nyos

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Lake Monoun

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Mohammed Musa Abdulahi woke one Saturday morning to find he couldn’t feelor move his right arm. He remembered he hadn’t been feeling well, that he hadgone to lie down inside the schoolhouse instead of taking care of the younger

students, as he sometimes did. He got up, his arm hanging uselessly at his side, and proddedhis friend, who also had come inside to take a nap. The friend jolted awake, cried out for noapparent reason and raced away. Abdulahi started to walk home through his village in north-western Cameroon and found it horrifyingly silent. The dirt roads and yards of Subum werelittered with corpses. People lay unmoving on the ground, as if they had fallen suddenly whilein the middle of a stroll or a conversation. The dogs were dead. The cattle were dead. Birdsand insects had dropped from the trees.

Abdulahi made his way to his father’s house, only to find that his entire family was alsodead—his brothers and sisters, his father and his father’s two wives. For a moment, though,there was a small hope. He touched one of the babies, and it began to cry. Abdulahi tried topick it up, but couldn’t because of his lifeless arm, so he made a crude sling out of cloth.When he touched the baby again, it too was dead.

“It is terrible to be without a family,” he says. “Everything you do, you feel not quite right.”Abdulahi tells me his story as we sit on the southern shore of Lake Nyos, the very lake thatspewed a cloud of lethal gas on the evening of Thursday, August 21, 1986, killing all 11 mem-

bers of his family and at least 1,700 other people. The very lake that could explode again atany moment. It is the first time Abdulahi has returned since the disaster—since he

spent two days in the coma that somehow saved him—and he is now a tall youngman of 29. “It is not that I made a decision not to come back,” he says in his

calm way. “It is just fate now.”It is indeed strange circumstance that has united Abdulahi and an in-ternational team of scientists who have come to Cameroon to study

the deadly lake in order to disarm it, if they ultimately can. Earlierthis afternoon Abdulahi walked down the mountains from the

CARBON DIOXIDE from deep in Lake Nyos (below) welledup in August 1986 and was responsible for killing about 1,700people and their livestock.

Killing Lakesthe

Two lakes in Cameroon are poised to release lethal gas,as they did in the 1980s. Writer Marguerite Hollowayreports on scientists’ efforts to prevent another tragedy

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The Killing Lakes Scientific American July 2000 93

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town of Eseh to the lake in his tan over-coat, black pants and black-and-whitechecked shirt. He brought a dapper pres-ence to the shore’s chaos of monitoringequipment, raft-building supplies, inflat-able boats, tents, coolers, mangy dogs,soon-to-be-cooked chickens, and fren-zied, unwashed scientists—and one un-kempt journalist—surrounded by theirentourage of several dozen local visitors.A day or so earlier a driver on his way tomeet the team at Lake Nyos had askedfor directions in the city of Bamenda andhad procured Abdulahi as a guide. Onlya week after he had watched a broadcastabout the team’s arrival in Yaoundé, thecapital, and had wondered how he couldbecome involved, Mohammed MusaAbdulahi found himself camping next toLake Nyos, taking part in the project.

For the team members, their October1999 arrival in Yaoundé had alsomarked a beginning. Since 1986 scien-tists studying Lake Nyos have sought torid the lake of the deadly gas that accu-mulates in its bottom waters before itexplodes again and kills thousands more.Degassing the lake is technologicallystraightforward—and in the context ofnatural-disaster prevention, easy andcheap. Yet accomplishing this relativelysimple task has proved astonishinglydifficult. Despite the clear urgency ofthe problem and the unique opportuni-ty to forestall natural disaster, little hasbeen done to protect the people aroundLake Nyos. Politics, lack of financialsupport (because of the reactive ratherthan preventive orientation of somefunding organizations), and miscom-munication have all interfered. But inYaoundé—despite the persistent andworrisome flickering of some of thesesame problems—it appeared thingswere finally about to happen.

Nyos is a stunning lake, surroundedvariously by cultivated fields, cathe-

dral-like rock faces and verdant hills.On the afternoon of Abdulahi’s arrivalit looks gray and glass-flat calm. But inits depths, Nyos is active. It is a craterlake, one formed by a volcanic eruptionabout five centuries ago that left a plugof magma at the bottom of the crater.This plug cooled and the depressionfilled with water, 210 meters deep. It isone of many such lakes found theworld over in volcanic chains—but oneof only two, it appears, that have everexploded and taken human life. Theother one, Lake Monoun, lies just 95kilometers to the southeast.

From deep volcanic activity, carbondioxide (CO2) gas rises up until it meetsgroundwater beneath the lake, dissolvesinto that water and flows into Nyos,carrying with it minerals, themselvesdissolved by the reactive gas. It accumu-lates in solution, staying separate fromthe upper layers of freshwater. In mostcrater lakes the lower water periodicallyturns over, bringing any gas-rich waterto the surface, where the gas diffusesharmlessly into the atmosphere. ButNyos and Monoun do notturn over. The boundary, calledthe chemocline, between themineralized, dense deep waterand the fresh upper waterstays dangerously intact. (Sim-ilar conditions prevail at LakeKivu in Rwanda and the Dem-ocratic Republic of Congo, al-though there is no record ofits having ever erupted.)

In these lakes the gas satu-rates the bottom water untilsome trigger—a strong wind,a violent storm, cool weatherthat causes a pocket of upperwater to sink, a landslide, anearthquake, no one knows—provokes a bit of deep waterto move upward. No longer

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1 Cornfields next to Lake Nyos2 Mohammed Musa Abdulahi3 Bridge between Bafumen and Eseh4 Memorial to the Lake Nyos victims

in the town of Bafumen5 George W. Kling6 Camp on the southern shore

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strong-armed by pressure, thecarbon dioxide comes out of so-lution; it bubbles to the surface,pulling more bottom water withit. It is thought that this uprisinggains momentum, a few bubblesbecoming a stream of bubblesand then, like champagne finallyuncorked, the gas-laden watererupts in a great fountain—atNyos, the jet was 80 metershigh—and carbon dioxide fillsthe air.

A weighty gas, half again asheavy as air, carbon dioxide hugsthe ground, suffocating anythingin its path. When Lake Monounexploded on August 15, 1984,37 people were killed. LakeNyos, which is larger and deeper,was more devastating. The cloudof gas rolled down the hills at anestimated 72 kilometers perhour, into valleys and villages upto 20 kilometers away. Accord-ing to George W. Kling—a Uni-versity of Michigan biologist whohas extensively studied both lakesand who is the leader of the team

Abdulahi has joined—the last person todie was a girl who, the morning afterthe explosion, descended into a ravinewhere the gas hung, heavy and low. Ab-dulahi thinks he and his friend weresaved because they were sleeping in aroom that somehow, despite the opendoor, protected them from the full on-slaught of gas. Abdulahi slept for abouttwo days, and because of lying on hisright arm for so long was unable to useit for several months. Abdulahi believes

the gas disturbed his friend’s mind—anobservation that is consistent with re-ports of disorientation in many of thesurvivors.

Lake Nyos is clearly poised to killagain, as is Lake Monoun. Accord-

ing to the most recent calculations byKling and chemist William C. Evans ofthe U.S. Geological Survey, Lake Nyoscontains twice as much carbon dioxideas was released during the explosion(0.4 cubic kilometer today, as opposedto only 0.17 cubic kilometer in 1986).Another explosion could also rupturethe fragile dam, or spillway, at thenorthern end of the lake, and the wa-ters could flow as far as Nigeria—drowning or displacing as many as10,000 people. Although the areaaround the lake was evacuated after thedisaster and 3,500 or so refugees reset-tled in safe places, many people areagain living nearby, drawn by the land’srichness. Cornfields abut the water’sedge on the southern side. Cattle grazethe hills around the lake under thewatchul eyes of their Fulani herders.And in the early 1990s some Europeanscientist released tilapia into the fishlesslake in an uncontrolled and unautho-rized experiment. The fish thrived, al-tering the ecosystem in unknown waysand becoming another incentive luringpeople to the lake. With few resourcesor possibilities for earning a living, theimpoverished people of the area havelittle choice but to approach the decep-tively benign-looking waters of Nyos.

Perhaps fortunately, the enormousdifficulty of reaching this beautiful spotkeeps outsiders away. Its remoteness,however, also makes it hard to studyand degas. Five days after arriving inYaoundé, we set out for Nyos in fourvehicles. Part of the team—Evans; Klingand his assistant, Karen J. Riseng; Mi-noru Kusakabe of Okayama Universityand four of his colleagues from variousinstitutions in Japan; Gregory Tanyilekeof the Cameroonian Institute for Geo-logical and Mining Research (IRGM)and I—take our places in two rentedNissan Patrols with their drivers. Theothers, including Tanyileke’s IRGM col-leagues—Hubert Mvogo, Jacob Nwalal,Paul Nia and Justin Nlozoa—drive twotrucks laden with equipment. We travelto Bamenda in comfort, passing loggingtrucks with some of Cameroon’s re-maining old-growth forests stackedhigh on their backs, passing red cocoabeans that smell like vinegar and fluffy

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white manioc spread on the side of thehighway to dry. We spend the night in ahotel, pick up supplies—including 36rolls of pink toilet paper for 14 people—and head to the end of the paved road atFundong. (We later run out of fresh wa-ter. We still have toilet paper.)

The single road heading north fromFundong is ghastly and effectively iso-lates the region around Lake Nyos. It ismore a series of vast muddy pits, con-nected, on a dry day, by an uneven dustytrail, than it is a road. For 13 kilome-ters we slip and slide and lurch andstick, and the sway bar on one of theNissans breaks. By late afternoon it isclear that despite Kling’s frustration wecan’t get any farther than the village ofBafumen. Members of the Japanese teamwisely find a house to stay in, and therest of us pitch our tents in a cemetery,right below a memorial to victims ofthe Nyos disaster. Lake Nyos is just 17or so kilometers away now, but it seemsas inaccessible as Yaoundé. And wordabout town is that the bridge on theroad to Eseh has been washed out.

We start out the next morning withfresh faith. The sway bar had been sol-dered back together, and the evening’schill softened by Bafumen’s supply ofwarm beer. After repairing the first flatof the day, we reach the bridge. It hasn’tbeen washed out. The left side is, in fact,intact. Only the right side is falling intothe river. The entire team descends fromthe vehicles, and there is much scientificand highly technical muttering aboutmass and stability and speed and loadand distribution, in the midst of whichMvogo jumps in the equipment truckhe commands—“The Grandmother”—and speeds her across. By the end of theday we have reached Eseh, spent hourswaiting out a downpour, and have setup camp after hiring the entire town tocarry, on their heads, all our things—in-cluding the hard, heavy suitcases infelic-itously packed by team members whothought we would be driving right tothe water’s edge—the six kilometersdown the steep slippery-when-wet pathto the lake. In the middle of camp weplace a blue crate filled with canisters ofoxygen: 10 minutes apiece for just 10of us. (Some of us initially try to set upour tents on a hill so that we will be saf-er if the lake decides to explode again.But it proves too difficult, and with asmall but nagging fear we pitch belowin the main camp.)

The first task the next morning is raftbuilding. After the explosion in 1986

Kling and his colleagues set up a cli-mate station on a raft in the middle ofthe lake to monitor temperature, wind,sun and rainfall. That station, beatenragged by the weather, no longer func-tions, and the raft needs replacing. Inaddition, the team needs to install ther-mistors that will hang from the newraft at nine different depths to recordchanges in temperature—which reflectthe movements and chemistry of thelake’s waters. They also need to lowerprobes to measure the carbon dioxide’spressure. Only once these instrumentsare in place will it be safe to thinkabout a major degassing. Every stage ofthat operation must be observed to seeif it is dangerously altering conditions.So the first order of business is to builda raft sturdy enough to hold the new

climate station, to anchor the variousprobes, and, if possible, to provide alarge enough platform from which thescientists can drop canisters to collectwater so they can measure carbon diox-ide concentrations. The Japanese con-tingent, under the direction of engineerYutaka Yoshida of Yoshida ConsultingEngineer Office in Iwate, Japan, takescharge of building the raft.

By the time Abdulahi arrives in camptwo days later, the raft has been com-pleted and the climate station assem-bled and attached to it. Abdulahi findsroom in one of the tents and borrowssome clothes for his stay. The followingday he helps Evans and Riseng withtheir work. The thermistors need to beunwound, marked for depth and taped

firmly together for stability, so Risengsends her assistants to the far ends ofthe cornfields with the long wires thatwill stretch nearly to the lake bottom.Seventeen men are scattered betweenthe bright-green plants, wires drapedover their shoulders—one of them, 201meters away, is barely visible on the ho-rizon of a field. Abdulahi helps Risengrewind the thermistors and then decidesto brave a trip on the lake, where hechecks the anchors for the new raft with

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1 Children from Eseh 2 The raft is launched 3 Climate station atop the raft 4 Spillway at the northern side of Lake Nyos 5 Hubert Mvogo helps unwind thermistors

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Evans and Tanyileke. The sun is blind-ingly hot. Some of us sit around campin a stupor. A Fulani gentleman bringsa gift of avocados. The day stretches on.

Abdulahi comes back from the lake.He now has one of the walkie-talkiesand has become a field coordinator,helping everyone find what, or whom,they need. We sit on a box of equip-ment and—between static-pocked de-mands from the transmitter—talk abouthis desire for a family. He says he hasmet a woman he wants to marry andwho wants to marry him, but her fami-ly has objected. They are hoping for arich suitor instead of an electrical engi-

neer, the occupation Abdulahi choseyears ago. “Why is this happening?” heasks sadly. “First my family, now a wife.”

With the raft done, the instrumentsdown and water samples collect-

ed, Kling and his colleagues have set thestage for the degassing operation thatwill, with luck, commence this fall orwinter. Over the past several years, Ku-sakabe and Yoshida prepared a $3-mil-lion plan to degas the lakes that wassubmitted to the Japanese InternationalCooperation Agency by the Cameroon-ian government. Their design entailsrunning 12 pipes into Nyos, at threedifferent depths, and allowing the CO2-laden water to froth up, perhaps at theinitial rate of 320 kilometers per hour,to release its gas. They envision threesuch pipes at Monoun.

This idea has been around, in variousiterations, since Lake Nyos exploded.And a version has been tested on bothlakes. In 1992 Michel Halbwachs ofthe University of Savoy secured fundingfrom the French government and the Eu-ropean Community to do a preliminarydegassing test in Monoun. Halbwachsand his colleagues, Tanyileke amongthem, lowered a five- and a 14-centime-ter-diameter pipe and, using a motor-ized pump, sucked up some bottomwater. Because of the pressure differen-tial, a self-sustaining fountain of gas-rich water gushed up in both pipes, andcarbon dioxide diffused away. Theywere able to close valves in the pipes toshut off the release.

The success of the Monoun projectled to a similar effort in 1995 at LakeNyos. With money from Gaz de France,Halbwachs and others lowered a 14-centimeter-wide, 205-meter-long pipe.Things did not go as smoothly as theyhad at Monoun, however, and after thefountain started, the pipe rose, terrify-ingly, from the bottom. Fortunately, noexplosion was triggered, and the experi-ments suggested degassing was feasible.

Halbwachs had a different plan fromYoshida and Kusakabe’s. His entailedonly five pipes for Nyos and a remoteon-off switch that could be controlledvia satellite from France. Although thescientists met in Yaoundé in October tohash out their disagreements, and ap-peared to do so, the conflict emerged aday later at a public meeting with mem-bers of a newly formed Cameroonianinterministerial committee on degassing.Halbwachs presented his five-pipe plan,and Kusakabe presented the 12-pipe

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version. The ministers focused on thediscord, and for a short and wrenchingtime it looked as though the entire proj-ect was going to be derailed.

Ultimately, Henri Hogbe Nlend, min-ister of scientific research and technolo-gy and head of the committee, reas-sured everyone that the disagreementswere petty. “Any number they give nowis false, everything is an estimate,” hesaid forcefully. “The technology thatthey have explained will keep evolv-ing.” No one, he added, should expect

the architects of a cathedral to supplyspecifics in the face of such a great en-terprise. Uniting the various ministriesbehind the operation had been a monu-mental task. Without their combinedsupport, the roads would not be im-proved, the areas around the lakes wouldnot be evacuated, and the Cameroon-ian military would not be present at thedegassings with oxygen tanks in case ofan explosion. Minister Nlend, appar-ently, was not going to let some minorgrievances thwart the project. And allthe scientists are collaborating again.

The disagreement was atypical for acommunity that has been largely

collaborative for more than a decade.The debate is partly the result of scientif-ic disagreement, but in truth, the differ-ences in designs are negligible. It appearsto have resulted more from a lack ofcommunication among the researchersabout, or during, their efforts to getfunding. Halbwachs felt excluded fromwork for which he had laid the founda-tion. The others say they were pursuingfunding catch-as-catch-can, thinking allalong that Halbwachs would workwith them. “We have always assumedthat anyone who cares about theselakes is working together,” Kling says.

Securing funding for the project hasindeed been a desperate venture. Hereare two lakes that will explode, thou-sands of people at risk and an easy solu-tion that could cost as little as $1 mil-lion. And yet. Although various re-searchers have received support fromtheir governments or their institutions tostudy the lakes, it has frustrated many of

them that they have not been able to getmoney to degas them. In 1992, for in-stance, a meeting on degassing was or-ganized with the support of UNESCOand the United Nations DevelopmentProgram. But neither institution put forthmoney for the actual project, Kling says.The scientists have tried some otherchannels with little success. Kling and acolleague tried to interest oil compa-nies—which have a powerful, lucrativepresence in Cameroon. No luck. Andthe same year as the U.N. conference,

Kling appealed to the U.S. Agency forInternational Development (AID) andwas refused because at that time theagency was not inclined to fund proj-ects in Cameroon. After helping the vic-tims just after the disasters, “AID haddisengaged somewhat,” explains Chris-tina Neal, a geologist in the agency’sOffice of Foreign Disaster Assistance(OFDA). “Cameroon had a problemwith democracy and good governance.”

Kusakabe’s efforts to get money fromthe Japanese International CooperationAgency came to naught as well. Somesay the Japanese government wasn’t ascommitted to the degassing as it was toother projects in Cameroon. Others saythat the Cameroonian government,which had to rate the project as thenumber-one aid priority to receivefunds, couldn’t reach consensus andthat one minister favored a well in hisvillage instead.

The politics may never be fully

plumbed, but the larger issue is thatmany aid organizations are responsive,not preventive. Many people within thiscommunity have emphasized the dan-gers of this approach. But OFDA’s Nealsays it has only lately begun to changeand points to recent mitigation efforts atAID and the Federal Emergency Man-agement Agency. “I think at AID therehas been a learning process and a cul-tural shift in the past few years that mit-igation is increasingly the importantway to approach problems and that byrunning in after an earthquake or mere-ly saving bodies and providing first aid,we don’t do anything for the long-termproblem,” she says.

It is in great part because of Neal’s in-terest in Cameroon and its lakes and be-cause of her strong belief in mitigationthat $433,000 finally came through forKling and the team last fall. The OFDAgrant was triggered by the eruption ofMount Cameroon in the spring of 1999.The office sent John P. Lockwood, for-merly of the U.S. Geological Survey, whohad studied Lake Nyos, to determinethe extent of the danger. After meetingwith U.S. Embassy representatives inYaoundé and Cameroonian scientists

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“We, the scientists, are stillwondering, was it enough tojust send reports to everyone?”

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and ministers, he concluded that ifOFDA really wanted to help Cam-eroon, it should do somethingabout the lakes.

Although the degassing seems tobe on track now, many researchersstill feel somehow guilty—as thoughthey should have done somethingmore and because they didn’t knowexactly what to do. Tanyileke wor-ries that he and the others werenot clear enough about the dan-ger—at least not in a way thatmoved anyone to act. “We, the sci-entists, are still wondering, was itenough to just send reports toeveryone?” says Tanyileke one lateafternoon at Nyos. We are sittingon a cooler in the sun, and theweight of the heat even late in theday is leaden, stupefying. “Theyweren’t strong enough to makethem sit up.”

As we talk, a nine-person dele-gation from Nyos village arrives.They are arrayed in finery—hats,umbrellas, bright robes—and bringa letter from their chief, Fon Tang-Nembong: “Our dear visitor weare very very happy to see you

people here in our lake. We here to saywill come to you all.” Tanyileke de-scribes what the team is doing and why.“An explosion could happen any day,”he warns, adding “if we are doing any-thing that is going against your tradi-tions, you must tell us.” All the mem-bers of the team, but Tanyileke andEvans in particular, try to explain theirwork to the people they meet.

Such communication is crucial formany reasons, not just for good rela-tions. It encourages people to be waryof the seemingly safe lake. It fosters sci-entific awareness that Tanyileke hopeswill contribute to making Nyos a re-search center once the lake is degassed.And, finally, it helps to quell an unhelp-ful rumor. The rumor began, accordingto anthropologist Eugenia Shanklin ofthe College of New Jersey, when a priestwho visited the devastated villages de-scribed the scene as resembling the af-termath of a neutron bomb. And so thebomb story was born. One version hasAmericans and Israelis detonating thedevice to get to diamonds under thelake. Another has a blond-haired PeaceCorps worker placing the bomb so thatAmericans could live in the region.

The rumor rankles the team—and thePeace Corps and the U.S. Embassy inYaoundé and, perhaps, the Israeli med-ics who provided disaster relief in1986—and could interfere with evacua-tion efforts during the degassing ifsome of those same groups participate.But Shanklin finds the emergence of amodern myth intriguing—just as in-triguing as the region’s ancient tales.One of the legends suggests that whathappened at Nyos and Monoun is notwithout precedent: a myth of the Kompeople describes a lake that suddenlyexploded and decimated a tribe.

For their part, the delegation fromNyos doesn’t seem suspicious of theteam’s work. “We are very happy foryour coming here,” Tamaki Cheteh says.“Everyone in Nyos is sick from this gas.”And then, in a request as remarkable asAbdulahi’s foray on the lake, a memberof the delegation asks to taste the waterthat killed many of his relatives. WithAbdulahi standing nearby, Tanyileke of-fers him some of the carbonated watercollected right near the bottom. Every-one gathers around, and, in turn, theydrink from the depths of their lake.

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SA1 Children hold thermistors at Lake Monoun 2 Gregory Tanyileke3 Villagers from Nyos drink from their lake4 Lake Monoun

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Readers interested in supporting the effort cansend contributions to the Cameroon DegassingProject, Dept. of Biology, University of Michigan,830 N. University, Ann Arbor, MI 48109-1048.


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The Killing Lakes