A limnic eruption, also known as a lake overturn, is a very rare type of natural disaster in which dissolved carbon dioxide (CO2) suddenly erupts from deep lake waters, forming a gas cloud capable of suffocating wildlife, livestock, and humans. A limnic eruption may also cause tsunami or seiche as the rising CO2 displaces water. Scientists believe earthquakes, volcanic activity, and other explosive events can serve as triggers for limnic eruptions.
To date, only two instances have been documented: Lake Monoun in 1984, causing 37 fatalities, and Lake Nyos in 1986, resulting in approximately 1,746 deaths and displacing around 4,500 individuals. These two high-altitude, geologically unique lakes in Cameroon account for 100% of known limnic eruptions, making this a geographically isolated phenomenon. However, with more than 300 similar high-altitude, stratified lakes worldwide, especially in East Africa and South America, the potential human impact of such eruptions could reach into tens of thousands, especially as populations continue to grow and climate change intensifies.