How Will the Last Gallon of Oil Be Used?

In his book Collapse: How Societies Choose to Fail or Succeed Jared Diamond wrote about the collapse of Easter Island amongst other failed civilizations. Easter Island is one of the most remote places in the world. Located in the South Pacific, it’s nearest habitable neighbor is over 1000 miles away. It’s over 2000 miles west of Chile. The island is thought to have been first inhabited by Polynesians between 700-1100 AD. Here is a description based on European eyewitnesses.

Easter Island has been cited as an example of a human population crash. When fewer than 100 humans first arrived, the island was covered with trees with a large variety of food types. In 1722, the island was visited by Jacob Roggeveen, who estimated a population of 2000 to 3000 inhabitants with very few trees, “a rich soil, good climate” and “all the county was under cultivation”. Half a century later, it was described as “a poor land” and “largely uncultivated”.
Source: Wikipedia

From archaeological evidence, early in its history Easter Island was a lush and fruitful Island. The island supported a unique culture until the population exhausted all of the available resources. In his book, Jared Diamond posed a question that stuck with me, he asked, what were the thoughts of the person that cut down that last tree on Easter Island as they were cutting it down? What was the branches, limbs, and wood of the last tree of Easter Island used for? Were the remains of that last tree used for shelter, for weapons, or for fire wood?

By some estimates, we have consumed about half of the world’s oil reserves in a little over a century and oil demand is only increasing. Whether or not these estimates are correct, one can imagine a time in the future when all the reaming oil will be down to one barrel. What will that last barrel of oil be used for?