Reuters: Millions of people in Nigeria could be displaced by rising sea levels in the next half century, as ocean surges swamp some of Africa’s most expensive real estate and its poorest slums, scientists say. Africa’s most populous nation, stretching from the southern fringe of the Sahara to the Gulf of Guinea, could come under triple attack from climate change as the desert encroaches on its northern pastures, rainfall erodes farmland in its eastern Niger Delta, and the Atlantic Ocean floods …