Natural disasters, wars and epidemics were seen as an act of God to blot out the evil part of Man and spare the good part.
And it will come about that in all the land, says the Lord, two parts of it will be cut off and come to an end; but the third will be still living there. And I will make the third part go through the fire, cleaning them as silver is made clean, and testing them as gold is tested: and they will make their prayer to me and I will give them an answer: I will say, It is my people; and they will say, The Lord is my God. Zech 13;8
This belongs to the refining process; exposing the ores to meaner and meaner acids revealing the few gold atoms that are left in them.
That's the idea, but Enlil wanted to wipe out the entire human race with a Flood and for the wrong reasons. So Enki devised a plan that a few good people were to be saved.
The Hindi speak of different ages of mankind. According to the Vedas we now live in the fourth era of mankind, the first was the golden era, the second was the silver era, the third, the bronze and the fourth; the Iron era, Kali yuga the present era.
These same eras were known to the Greek and also to the Armenians;
"Cold has become silver, silver has become copper, copper has become cast- iron and the human being has become mean" Armenian tale of Noah’s ark
These Disasters and Epidemics haven't produced a better race yet, on earth that is, but the idea is that man has to get so fed up with wars, violence and greed, that no one will even consider these things in the new world to come. And that is why God is allowing this to happen now.