In 1986, Lake Nyos released a deadly carbon dioxide cloud that killed 1,746 people, but the gas was still building up 30 years later | World News
Lake Nyos looks deceptively ordinary in photographs. It sits in a volcanic landscape in north-western Cameroon, surrounded by steep green slopes and farmland. Yet beneath its surface, an unusual geological process once allowed enormous quantities of carbon dioxide to accumulate in deep water.On 21 August 1986, that gas escaped suddenly. A dense cloud of carbon…