Buddhist eschatology, as subscribed by some Buddhist schools, derives from purported Gautama Buddha's prediction that his teachings would disappear after 5,000 years. According to theSutta Pitaka, the "ten moral courses of conduct" will disappear and people will follow the ten amoral concepts of theft, violence, murder, lying, evil speaking, adultery, abusive and idle talk, covetousness and ill will, wanton greed, and perverted lust resulting in skyrocketing poverty and the end of the worldly laws of true dharma.
During the Middle Ages, the span of time was expanded to 5,000 years. Commentators like Buddhaghosa predicted a step-by-step disappearance of the Buddha's teachings.During the first stage, arahants would no longer appear in the world. Later, the content of the Buddha's true teachings would vanish, and only their form would be preserved. Finally, even the form of the Dharma would be forgotten. During the final stage, the memory of the Buddha himself would be forgotten, and the last of his relics would be gathered together in Bodh Gaya and cremated. Some time following this development a new Buddha named Maitreya will arise to renew the teachings of Buddhism and rediscover the path to Nirvana. Maitreya is believed to currently reside in the Tuṣita heaven, where he is awaiting his final rebirth in the world.
The decline of Buddhism in the world, and its eventual re-establishment by Maitreya, are in keeping with the general shape of Buddhist cosmology. Like Hindus, Buddhists generally believe in a cycle of creation and destruction, of which the current epoch represents only the latest step. The historical Buddha Shakyamuni is only the latest in a series of Buddhas that stretches back into the past.
The belief in the decline and disappearance of Buddhism in the world has exerted significant influence in the development of Buddhism since the time of the Buddha. In Vajrayana Buddhism and various other forms of esoteric Buddhism, the use of tantra is justified by the degenerate state of the present world. The East Asian belief in the decline of the Dharma (called mappo in Japanese) was instrumental in the emergence of Pure Land Buddhism. Within the Theravada tradition, debate over whether Nirvana was still attainable in the present age helped prompt the creation of the Dhammayutt Order inThailand.
In China, Buddhist eschatology was strengthened by the Daoist influence: the messianic features of Maitreya are widely emphasized. The figure of Prince Moonlight 月光童子 obtains prominence unknown in the Sanskrit sources. Thus, one of the Tang dynasty apocrypha predicts his rebirth in the female form, thus creating religious legitimacy for the Wu Zetian Empress's usurpation. Furthering the Daoist associations, the "Sutra of Samantabhadra" portrays Prince Moonlight dwelling on the Penglai Island in a cave.
Buddhism believes in cycles in which life span of human beings changes according to human nature. In Cakkavati sutta the Buddha explained the relationship between life span of human being and behaviour. As per this sutta, In the past unskillful behavior was unknown among the human race. As a result, people lived for an immensely long time — 80,000 years — endowed with great beauty, wealth, pleasure, and strength. Over the course of time, though, they began behaving in various unskillful ways. This caused the human life span gradually to shorten, to the point where it now stands at 100 years, with human beauty, wealth, pleasure, and strength decreasing proportionately. In the future, as morality continues to degenerate, human life will continue to shorten to the point were the normal life span is 10 years, with people reaching sexual maturity at five.
Ultimately, conditions will deteriorate to the point of a "sword-interval," in which swords appear in the hands of all human beings, and they hunt one another like game. A few people, however, will take shelter in the wilderness to escape the carnage, and when the slaughter is over, they will come out of hiding and resolve to take up a life of skillful and virtuous action again. With the recovery of virtue, the human life span will gradually increase again until it reaches 80,000 years, with people attaining sexual maturity at 500.
According to Tibetan Buddhist literature, the first Buddha lived 1,000,000 years and was 100 cubits tall while the 28th Buddha, Siddhartha Gautama (563BC–483BC) lived 80 years and his height was 20 cubits. This is on par with the Hindu eschatology which says this age to be the 28th Kaliyuga.