How many years of oil is left on the earth?

How many years of oil is left on earth depends on reserves, consumption, and technology, but common estimates are 40 to 60 years of proven reserves at current consumption. Proven reserves are about 1.7 trillion barrels, consumption about 100 million barrels per day or 36.5 billion barrels per year, division gives about 47 years. However, this does not mean oil runs out in 47 years, as new reserves are discovered, extraction technology improves unlocking shale, oil sands, and deepwater oil, and technically recoverable resources are much larger, perhaps 2 to 3 trillion barrels more, extending timeline to 70 to 100 years. Also demand may decline due to electric vehicles and renewables, extending years left. Peak oil theory suggests production may peak before reserves run out, making oil harder and more expensive to extract, leading to price rises and transition. So oil will not suddenly run out, but cheap easily accessible oil will become scarcer. Most experts say 40 to 60 years of proven reserves at current rates, but likely longer with new technology and reduced demand, and complete exhaustion not expected for many decades to over a century, though economic exhaustion may come sooner.