The first and third laws of consumption can be used with basic physics to project the maximum life expectancy of the human population.
First, the bottom line: Maximum life expectancy is 134 years. This can only be attained if the average speed of resource movement reaches the speed of light. At this point, there would be nearly 9.3 trillion people occupying the space of a sphere half a light year across. To keep such a population functioning, we would need the equivalent of teleportation (such as Star Trek’s transporters), capable of connecting an average of nearly 300 thousand people per second and enabling the consumption of an estimated two-millionths of Earth’s mass per year.
The time it would take to deplete all accessible resources would be one 55-billionth of the time it would take for a population of 40 million people to deplete its resources, where 40 million is the size of a community (“super-group”) where members could be aware of everyone else if they communicated for one hour a day for an entire year. The number of super-groups in the entire population would be over 233 thousand, or the number of hours in more than 26 years – roughly the number of years in a generation! (If these facts don’t twist your mind into a knot, consider the following: The maximum life expectancy is almost exactly five times the actual number of “years” I just quoted.)
If we could divide Earth’s mass equally among 12 billion people (roughly twice the number now in the world) one of those pieces would be all that we now have left to work with. Accessing the equivalent of those other pieces would enable our current population to last as long as cosmic events allow us to with no increase in life expectancy, but reaching the maximum life expectancy would reduce the longevity of our species to less than 500 thousand years.