The best known of these problems is, of course, the development of military technologies powerful enough to eradicate mankind. One of the reasons for the destruction of Babylon is that she will have polluted the land. Subtle environmental changes can make a population susceptible to epidemic disease. Crowding is clearly such a change, and the density of human population is rising both locally and globally. Malnutrition is another, and this condition today affects perhaps two-thirds of mankind.
War is another.
The descriptions of the wars before the last war of Armageddon suggest that it will be nuclear. Another is the uncontrolled use of our natural resources without replenishing them.