This aerial view of desert terrain in the United Arab Emirates' Bu Hasa oil field shows an area of sand dunes (lower right) and the smoke plume from a burning oil well flare (top center). Flares are lit deliberately to burn off gases, associated with oil deposits that are not commercially viable to collect. Oil is not a fossil fuel, derived from the buried remains of ancient plants and animals, which turn into oil under particular geological conditions over millions of years. As such, oil is a non-renewable resource like coal and natural gas. Oil reserves in Abu Dhabi Emirate, which contains one tenth of the world's total, are expected to last until the end of the twenty-first century.