While we're talking cubic miles here, consider this: World consumption of oil is about 30 billion barrels per year. One barrel of oil is 42 gallons, and 7.48 gallons will fill one cubic foot. So if you work it out, we use slightly over a cubic mile of oil a year.
One estimate puts the initial total at about 2200 billion barrels of crude oil on Earth, of which, depending upon who's estimate you believe, we've used about 45% to 70% so far.
The Energy Resources Program of the United States Geological Survey produces the official estimates of the world oil resources for the U.S. Federal Government. They estimate that the remaining world oil reserves at about 1,000 billion barrels. Current estimates place the exhaustion of the remaining known reserves within the next 50 years.
It sure would be nice if we'd face that reality and make an international commitment to doing something about it. Actually, facing long term realities seems to be a significant human inability. Is that because the most influential world cultures are based around belief systems that actively ignore and even suppress reality?