Limnic eruptions are well outside of public consciousness. Not surprising, considering their extreme rarity. In all of recorded human history we only know of two for certain. Both occurred in Africa in the 1980s; one at Lake Monoun in 1984 and then a particularly deadly one at Lake Nyos, Cameroon in 1986. The latter killed as many as 1,800 people and the lakes have yet to fully recover.
Not only are limnic eruptions among the rarest natural disasters, they are also some of the most bizarre-and terrifying. Basically, a limnic eruption is when a large body of water suddenly releases large amounts of carbon dioxide which, being heavier than air, displaces it at ground level, suffocating oxygen breathers.
Image via Dibussi
Lake Nyos before and after the eruption. Iron, forced to the surface of Lake Nyos after the eruption, oxidised, turning the lake a brown rust colour.
Another probable reason North Americans and Europeans know little about this phenomenon is that they can only occur in areas that are both tropical and prone to volcanic activity. The body of water must also be quite deep. So we can all breath easy, right? We may, if new reports turn out to be wrong.
Image: Geo Arizona
These new reports suggest that much larger bodies of water, the world's oceans, may also be at risk. No other bodies of water are deeper or more volcanic, and the amount of carbon dioxide they can hold is mind boggling. Carbon dioxide levels in the atmosphere have reached almost eight times the current level on more than one occasion in Earth's history, leading some scientists to speculate that limnic eruptions have occurred in our oceans before, and may happen again. Of course, these were tens of millions of years apart. Whether there is any immediate danger or not, the idea reaffirms two things most of us have known for years. One is that our carbon emissions could one day screw us over (now we just know another way for it to kill us all). Second, science really has a fetish for scaring us.