Throughout history, humans have squabbled with each other — for example, two adolescent males competing for the attention of a female. The resulting fights cause injuries, but rarely do the combatants kill one another.
More commonly, killing at a large scale takes place when groups of people are convinced by their leaders, or compelling orators, that resources are scarce, and that they must eliminate a rival faction if they themselves are to survive.
In short, the best way to stoke the fires of murderous anger is the sentiment: ‘Kill or Be Killed‘.
Historically, warring over land — that can cultivated to produce crops or hunted upon to take wild animals for food — was the most common manifestation of this.
However, since the end of World War II, fossil fuels have become the limited resource of choice that has frequently been used to justify the right to kill others in large numbers. After all, Energy is Life in many respects, and without it, you will be weaker, and more readily controlled or taken over by other cultures / tribes.
If we can continue our evolution, end our dependence upon fossil fuels, and embrace unlimited, zero-fuel-cost sustainable energy sources, such as wind, solar and geothermal, then we can relieve the human race of this awful & destructive competitive urge to harm each other to merely survive the cold winter.
With unlimited clean energy, not only can we all survive, but we can thrive and elevate all the World’s population to a much higher standard of living, and then who knows, perhaps even explore the stars.