“We are our own greatest threat. We are all so worried about people dying all over the world, due to the machinations of other people, the spread of disease, famine, drought, wars, genocide and natural disasters, but consider what would have happened if all the calamities of the past had not happened. All those people who died would not have met untimely ends and would all have procreated as most people are doing now. 

Mankind would long ago have overrun every square centimetre of the planet, leaving no space in which to grow food. All resources would have dried up; pollution, including our excrement, would have reached toxic levels; there would have been no pure water to drink … mankind and every other living organism would have become extinct and Earth would have been no different from any other barren piece of rock in the solar system.  

Mankind is unable to control his reproductive urges, yet he is the only creature on earth with the capacity to contemplate doing so. It is not as though he is an endangered species, but he breeds away without giving a thought to the impact it will have on the planet in the future and whether he can afford to support his offspring or not.
There are so many unsolved mysteries right here on the ground, yet he prides himself on his

ability to waste vast sums of money on sending craft into space and to explore other nearby heavenly bodies. 
He sends all his healthiest specimens to be killed in wars, retaining the sick, the lame and the lazy to propagate his species. 
Is this small sample a sign of mankind’s vaunted intelligence? If they are, then mankind is truly his own greatest threat.”