I recently read in an environmental science textbook that proved oil reserves will be depleted between 2050 and 2100, depending on consumption rates. The commercial press seldom mentions depletion at all, and most politicians either don't know about it or won't talk about it.
On the notebook page reproduced below I have calculated depletion dates between 2020 (case 2) and 2050 (case1). I have shown two of hundreds of possible examples along with their simplistic assumptions. While case 2 (depletion in less than 10 years) will not happen, it does illustrate that the U. S. is a good (or bad) example of resource consumption.
It seems to me, however, that there are at least four obvious trends that favor depletion before 2050.
1. According to resource economics textbooks, we should reduce the amount of proved reserves by 20% because once people realize that we are consuming a fixed amount, the dwindling supply and rising demand will make the last 20% unaffordable. So, the reserves are less than what's estimated.
2. By 2025 the human population will have increased by a billion people. This might affect consumption. From 2025 to 2050 the population is projected to increase again by more than another billion.
3. Case 1 (below) assumes that consumption remains at 2010 levels until the oil runs out. This seems unlikely, at least for the next few decades. A look at figure 1 (right) from the Vital Signs 2012 chapter cited below suggests that consumption is increasing, especially in the developing world and in the emerging economies (e.g. Brazil, Russia, India, etc.).
4. The fourth trend for continued consumption is our dogged reluctance to recognize in any practical way the impacts of climate change or of the carbon dioxide emissions from burning oil (43% of total carbon emissions originate from oil use).