Who is the most important enemy of mankind?Volcanoes, asteroids, explosion of supernew... All this for so not for long living people - only exotic. To whom it is interesting what will occur through how many - that thousands of years? The most important enemy of mankind - ourselves. Our civilization only several tens of thousands of years (watching how to consider if from writing emergence, and 5000 years are not gathered). And how many we already managed to commit follies? And in direct, and figuratively.
When in the Middle Ages in Europe one by one epidemics of smallpox, cholera, plague devastated the countries, leaving behind in live a half or even a third of the population, it did not threaten existence of mankind.
When as a result of explosion of a volcano Santorini died several most then the developed civilizations of the Mediterranean, and caused by explosion of a volcano of a tsunami gushed over even mountains on the island of Crete - it ruined a Minoan civilization, but to the become empty lands barbarians came then from other countries...
There passed time. The person did not become cleverer at all, but became more dangerous - both to himself, and to existence of the life on Earth.
We saved up mountains of the weapon. Both simple, and nuclear. The person last century just by mistake more than ten times nearly untied a nuclear slaughter, war after which on Earth on hundreds and thousands of years life would be impossible. We would destroy also ourselves, and almost all live on the planet, probably, only cockroaches and survived.
And through how many - that millions of years the new reasonable civilization on the basis of researches of the geologists would claim about seven periods of mass extinctions of living beings of Earth. Like, in the beginning trilobita died out, armored fishes, then then died out..., then..., dinosaurs died out then, but on their place later many million years mammals who died out later about 100 million years after dinosaurs too developed. Died most likely from - for falling of huge meteorites since in this layer of sedimentary breeds radioactive isotopes which were probably formed as a result of long radiation of asteroids in space by space beams meet.
And for it was a little and it is necessary. That on one of the atomic bombs (which dropped out of the American B - 52, being on alert), fallen in Greenland, or in Spain, or at all in the territory of the USA, would not work adequately a safety lock. One of many - operation of one safety lock when the others, having received injury from blow, did not work as is necessary, saved many years ago the world from nuclear suicide. In Spain the fallen hydrogen bomb blew up - on our happiness, detonators worked not synchronously and instead of squeezing the uranium sphere, they scattered uranium in different directions, having infected with radioactive isotopes huge territories. And there were several such cases.
And rockets were already ready to fly up when the satellite of early detection counted a certain close and weak reflection for distant and strong, having given a false signal of start in the USSR of two ballistic missiles. Still then couple of mistakes - and the USA by mistake would launch the missiles across the USSR. And further - the answer of the USSR would go... And through many million years those who would succeed us, would argue on the reasons of the seventh era of mass extinction of animals on Earth and on whether there could be reasonable mammals.
But even without direct self-extermination of people does very much to make Earth unsuitable for accommodation of people on it! We fell trees in Amazonia, and they are easy planets, than think to breathe the people ruining the future of and the children in a pursuit of a momentary profit?
The oil-extracting companies at oil production from an ocean floor at accidents throw out millions of tons of oil in water, poisoning water of oceans and killing plankton which is also food supply for many species of marine animals in addition - develops oxygen not less, than the woods of Amazonia.
Many millions of years the nature slowly and with diligence put hydrocarbons, oil and natural gas to the storerooms. We get them only slightly more than hundred years. And stocks remained all on how many - that decades. And then? What to do then?
The same is with other minerals. Something will be enough for us for several decades, something - for several hundreds... And what will be then?
So who, how not the person, most important enemy of mankind?