The Deadly Secret of Lake Nyos

Have you ever heard of the world's deadliest fart? Well, let's take a journey to Cameroon, a country renowned for its coffee, cotton, and cacao, not to mention its impressive football team, the Indomitable Lions, who have qualified for the World Cup a remarkable nine times, an achievement unmatched by any other African team.

Cameroon's best performance in the World Cup came in 1990 when they reached the quarter-finals, narrowly losing to the Three Lions of England in extra time. Although England went on to lose on penalties in the semi-finals, we'll save that story for another time or perhaps another channel. But for now, let's delve into the tale of the fatal fart.

Cameroon, with its population of 25 million people and over 250 native languages, is home to a story so surreal that it has forever etched the country on the world map. On August 21, 1986, in the desolate reaches of Lake Nyos in the North-West, a natural disaster occurred, or more accurately, a limnic eruption. This catastrophe claimed the lives of around 1,800 people and 3,500 livestock. While technically a volcanic eruption, it was unlike anything we typically associate with volcanoes. Instead of spewing lava and smoke, this eruption manifested as a massive gas cloud.

Lake Nyos, a deep crater lake situated high on the side of an inactive volcano in the Oku volcanic plain, is part of the "Cameroon line," a chain of volcanoes stretching over 1,600 kilometers. Despite the inherent risks, areas around volcanoes are fertile for farming and, consequently, densely populated. Just consider the two million people living near Mount Vesuvius near Naples, cultivating the world's best tomatoes in the rich volcanic soil and creating the most divine pizzas known to man.

The region around Lake Nyos was no exception. In 1986, it was home to a large populace engaged in farming crops and raising cattle. The Bafmen, who had inhabited the area for centuries, had a tradition of building their houses on elevated ground above the lake, never below it. This tradition was rooted in local folklore, which spoke of lakes exhibiting mysterious behavior such as rising and falling, changing locations, or even exploding.

Scholars speculate that these beliefs were shaped by past events and passed down through oral tradition, unfortunately left unrecorded. If only they had been documented, perhaps thousands of lives could have been saved. The ticking time bomb beneath Lake Nyos was a silent but deadly magma chamber, located around 50 miles beneath the lake's surface.

Gradually, the magma released gases, including carbon dioxide, which permeated the surrounding rock before seeping into the lake itself. This process is known to occur in only a few lakes worldwide, notably Lake Kivu in the Democratic Republic of the Congo and Lake Monoun in Cameroon.

As the gas traveled through the rock, it dissolved into the water. When the lake's waters stratified and didn't mix, a significant buildup of gas, particularly carbon dioxide, occurred in the lower layers. This gas could remain stable for some time. However, a sudden mixing of the upper and lower levels triggered a limnic eruption, comparable to opening a bottle of champagne or, for a more colorful analogy, farting in the bath.

This is precisely what happened at Lake Nyos. Several weeks before the calamitous event, a chilling sight greeted the locals one morning - all the fish in the lake had died overnight, their lifeless bodies floating on the surface. Carbon dioxide levels had reached a fatal concentration in the lake's depths, asphyxiating nearly all living creatures within.

Then, a few weeks later, the explosion occurred. Since then, scientists have been trying to determine what disturbed this deadly carbon dioxide cache. The triggering event could have been a rock fall that mixed the water layers, a minor earthquake, or even a small volcanic eruption at the lake's bottom, although no tremors were reported by survivors.

Regardless of the cause, a massive amount of carbon dioxide was suddenly released, estimated to be between 100,000 and 1.6 million tons. Due to the eruption's inertia, the carbon dioxide shot upwards at 60 miles per hour. At 9 pm on that fateful day, villagers heard a rumbling noise and emerged from their homes to investigate.

They witnessed gas gushing upwards, forming a cloud reaching up to 100 meters. Survivors described a white mist escaping from the lake. However, what goes up must come down, especially when it's carbon dioxide, one-and-a-half times denser than air. The cloud rapidly descended back to the lake's surface before billowing outwards like dropping marbles on a glass pane.

Within seconds, the gas cloud escaped from the confines of the lake, rushing down the valley in a wave that reached a height of fifty meters with alarming speed. As the carbon dioxide surged forward, it displaced the air, causing people in its path to lose consciousness. The silent and invisible killer, colorless and odorless, claimed human and animal lives alike.

Victims collapsed before suffocating, and the strong concentration of carbon dioxide caused not only immediate deaths but also left survivors with breathing problems, skin lesions, and paralysis. Other volcanic gases were present as well, survivors recalling the smell of rotten eggs, a sign of sulphur dioxide, but it was the carbon dioxide that proved most pernicious.

The scenes that greeted survivors the following morning were haunting - a deathly silence without the usual birdsong or buzzing of insects. People and animals lay where they had fallen, and it took some survivors more than a day to awaken. Many believed it was the end of the world. Scientists from different nations were mobilized, but initially, they were baffled. Numerous theories were proposed, from a vicious virus epidemic to a dormant volcano emitting poisonous gases. However, these ideas were quickly dismissed as they didn't fit the evidence.

The true explanation for the tragedy would gradually unfold over the months and years that followed, although a similar incident had occurred at nearby Lake Monoun two years earlier, resulting in 37 deaths. However, at that time, the concept of a limnic eruption was not fully understood, and those deaths were recorded as unexplained. The toll of lost lives at Lake Nyos prompted authorities to take such events more seriously, and scientists worked tirelessly to uncover the cause.

One of their conclusions was that a similar tragedy could occur again. As a preventive measure, they devised a plan to release the gas from the lowest depths of the lake through long tubes. Initially, water needed to be pumped up through the pipe, but once operational, the outflow of gas from the ascending water created a self-sustaining effect that continuously drew more water upwards. This mechanism, akin to siphoning petrol out of a car, proved successful.

In 2001, the first pipe was installed in Lake Nyos, followed by two more a decade later. However, by 2019, it was evident that a single pipe was sufficient to keep the carbon dioxide levels in check. That single pipe remains in place to this day, ensuring the safety of the residents and protecting them from the threat of another catastrophic gas eruption.