We’re all familiar with the problem of “natural evil” and the problems it poses for a benevolent creator god. We all know about earthquakes, tsunamis, floods, and so on. But, I recently heard about a bizarre natural disaster that happened back in 1986.
Lake Nyos is located in central Africa. A pocket of magma leaks CO2 into the lake, causing it to build-up over time. Occasionally, there is a chain reaction that causes the CO2 to suddenly burst out of the lake. The CO2, which was colder and heavier than normal air, flows into the surrounding area, suffocating and killing life.
It is thought that recent high rainfall had displaced the CO2-rich water at the bottom, releasing a massive bubble of carbon dioxide gas from the lake in a natural phenomenon now referred to as “lake overturn”.
The heavy gas then sank to the ground and rolled in a cloud several tens of metres deep across the surrounding countryside.
The gas killed all living things within a 15-mile (25km) radius of the lake
On August 21, 1986, a limnic eruption occurred at Lake Nyos which triggered the sudden release of about 1.6 million tonnes of CO2; this cloud rose at nearly 100 kilometres (62 mi) per hour. The gas spilled over the northern lip of the lake into a valley running roughly east-west from Cha to Subum, and then rushed down two valleys branching off it to the north, displacing all the air and suffocating some 1,700 people within 20 kilometres (12 mi) of the lake, mostly rural villagers, as well as 3,500 livestock.
This type of event happens periodically to the lake, and people living around the area had myths about evil spirits who periodically came out of the lake and killed people. (An interesting pre-scientific explanation for the events.) When you think about the details, it makes sense why non-scientific people would interpret it as evil spirits – there would be the sound of gas suddenly erupting from the lake, cold smelly air would flow into the countryside, the CO2 would extinguish flames (including lamps or candles), people would become weak, unconscious, and many people and animals would die. It all sounds very creepy.
Since that time, scientists have placed pipes into the lake to degas it, preventing this tragedy from happening again. (Yay science!) But, there are other lakes in Africa which have this same problem.