A second chance
According to the legend, Dread Velsparge, Daemon Prince of the Myriad Hands, plunged into the Tarakhen Sea in a blaze of scarlet flame, throwing the whole world into ruin.
During certain years, people in Akgku claim to observe a green flame coming from the sea and erupting upward. It can be observed from a distance of two days’ journey or more. After burning for a considerable time, the flame disappears.
—Falklyde Wodinger, Haraconian scholar, in route to wondrous Udross and legendary Akgku.
As population increases, animal souls are promoted to human before they are spiritually advanced enough in terms of impulse control, etc.: this shouldn't have happened, but karmic progression is automatic, after all--it's a force of nature. But the 'animalization' of humankind bodes ill for civilization.
No doubt the same goes for elves, dwarves, and so on.