Burning fuels for energy production
We presently live by burning fuels for energy production. These fuels are being depleted. Oil and gas and nuclear fission fuel may be depleted in 60 years. Coal may last a bid longer. Most of the depletion has occurred in the last 200 years in the 6000 years history of our civilization. Before large-scale energy development began, the only energy resource we had, was wood taken from the land, or oil from fish. The poverty that corresponds with this primitive living, has kept humanity small.
However, once we freed ourselves from the primitive poverty, we found that the needed energy resources that give us our advanced freedom from poverty, are inherently finite. Thus, the question needs to be asked, "what will happen to us when the resources that we rely on have been used up. We may be at this stage in 100 years, or the final depletion may be delayed a 1000 years if we curtail energy use with murderous consequences. When we get to this point, will we lay ourselves down to die? Even if we would restart the nuclear fast-breeder technology that enables the fuller utilization of the available nuclear fuel, by a factor of 20, we would still run out of fuel in roughly 1000 years?
The bottom line is, that our terrestrial fuel resources are so minuscule and finite that we won't have anything left of them 1000 years from now, or potentially much sooner than that.
What will power our economy then, through the next 90,000 years of the coming glaciation period, which will be upon us, potentially, in the 2050s? What will power our world when the presently used energy fuels are depleted? What will power our world for the many millions of years into the future that humanity has the potential to have on the Earth?