The world uses 85 million barrels a day.
At 42 gallons to the barrel, that’s three billion, five hundred and seventy million gallons of oil (3,570,000,000).
Niagara falls has a flow rate of 150,000 U.S. gallons per second.
3,570,000,000 of oil / 150,000 gallons per second = 23,800 seconds of flow equivalent.
In other words, if by some horrific means you were able to replace the flow over niagara falls with nothing but oil for 6.6 hours a day, that’s how much oil the 6 billion inhabitants of the earth burn every single day of every year, and have been for more or less the past ten years.