In 1986, fishermen and villagers in northwest Cameroon experienced one of the world’s strangest natural disasters. Lake Nyos, a crater lake near a chain of volcanoes, exploded. A massive cloud of carbon dioxide released into the air suffocated people and livestock as far as 16 miles away within minutes. More than 1,700 people died.
Scientists now attribute the explosion to a “limnic eruption,” when gases at the bottom of a lake, usually kept under by the weight of the water above it, are disturbed and rise to the surface—similar to taking the cap off of a shaken bottle of soda. Researchers are nervous an even larger explosion could strike one of Africa’s largest Great Lakes, Lake Kivu, which contains at least 60 billion cubic meters of methane and 300 billion cubic meters of carbon dioxide.
Rwanda and the Democratic Republic of Congo have agreed on a five-year agreement to explore for oil under the lake. “This could release a powerful explosion, due to gas expansion, such as happened on Nyos – but potentially much larger,” Robert Hecky, of the Large Lakes Observatory at the University of Minnesota who has been researching the lake since 2012, writes in the Conversation. “Because of its much greater size and gas content, Kivu has the potential for a cataclysmic gas release.”
Where Lake Nyos was only about 1.6 square kilometers, Lake Kivu covers about 2,700 square kilometers. The Lake Kivu basin also has one of the highest population densities in African Great Lakes. It’s home to about 2 million people, including several refugee camps. The area is also an important transport corridor for fish, produce, and other goods between Rwanda and the DRC, Hecky observes.
An explosion isn’t unavoidable. Methane gas is already being extracted, for electricity production, a process that gradually reduces pressure in the lake and lowers the chance of “spontaneous degassing.”
There are less risky ways to explore for oil in the lake. Hecky advises against doing exploratory drilling on the lake. Land-based drilling from the shore would reduce the chance of disturbing the lake. Still, eliminating all risk is impossible, he writes, offering a second piece of advice: “Insurance should be sought or bonds posted to guarantee that funds would be available if anything goes badly wrong.”