Old age I think is nature’s way of saying “You’re no longer welcome to pollute Earth’s surface, it’s time you exchanged your body for its nutrient content.” That’s where the saying “dust be to dust” comes from. Nature has its own mechanism for maintaining energy equilibrium—to only let a human live to the point that his energy use during his time on Earth is fully refunded to the Earth when he dies, in the form of nutritional content to the soil and other animals. But man has devised a way of cheating nature, of taking what he needs on a daily basis but for a prolonged period of time: nearly a century instead of a couple decades. Our innovative discoveries are a result of mental evolution—a concept that Paul Ehrlich attributes to the ecological crisis. Our minds are producing technological ideas for which an individual would need at least twice the average (read: normal) body mass in order to function on its own. For example, if the average American were to incorporate into his own body (physical evolution) the manufacturing equipment used to produce only the food he would eat in a day, as well as his laptop, his phone, and his shelter, the average American would be much larger than he is today (that’s a scary thought). Yet, the body mass we return to the Earth is only a fraction of this.
I think there are many other factors contributing to this “biomass imbalance,” like how much energy does a single person use to survive one day using the convenience of gasoline-powered transportation today versus the energy a Neanderthal used to walk from a cave and kill a Wooly Mammoth (which would hopefully feed him for several weeks). That is, what is the base energy used per day considering a hunter-gatherer lifestyle? And, if we calculated this value today, would it be skewed because of a shift in NPP due to climate change?
My conclusions about solutions for problems like this always seem to be pessimistic, that there will never be a solution, except for more chaos and entropy, which will eventually lead to catastrophic destruction and population crashes. If the theory of conservation of energy holds true for the Earth’s ecosystems (considered a closed system), then where in the world is all the extra mechanical energy humans expend going? With an exponentially growing world population, it would make sense that plant and other animal populations are being extirpated in order to make room for our increasing biomass, and if our exponentially increasing energy consumption places a great enough force on ecosystems to produce more than they can inherently supply, then they will exert an equal and opposite force on the human population—likely one we cannot resist.