The Church has not changed her teaching on the eternal punishment of hell. We choose to go there when we refuse to accept God’s love, or His Mercy. It’s our own choice. While there is always some debate over what the actual punishments might be (even though Jesus calls it “the pool of fire”), the fact remains that hell is eternal. After the resurrection and Final Judgement of all souls at the Second Coming of Christ, those who freely choose to go there will suffer in body and soul, for all eternity.
From the Catechism:1033 We cannot be united with God unless we freely choose to love him. But we cannot love God if we sin gravely against him, against our neighbor or against ourselves: "He who does not love remains in death. Anyone who hates his brother is a murderer, and you know that no murderer has eternal life abiding in him."612 Our Lord warns us that we shall be separated from him if we fail to meet the serious needs of the poor and the little ones who are his brethren.613 To die in mortal sin without repenting and accepting God’s merciful love means remaining separated from him for ever by our own free choice. This state of definitive self-exclusion from communion with God and the blessed is called "hell."
1034 **Jesus often speaks of “Gehenna” of “the unquenchable fire” reserved for those who to the end of their lives refuse to believe and be converted, where both soul and body can be lost.**614 Jesus solemnly proclaims that he "will send his angels, and they will gather . . . all evil doers, and throw them into the furnace of fire,"615 and that he will pronounce the condemnation: **“Depart from me, you cursed, into the eternal fire!”**616
1035 The teaching of the Church affirms the existence of hell and its eternity. Immediately after death the souls of those who die in a state of mortal sin descend into hell, where they suffer the punishments of hell, **“eternal fire.”**617 The chief punishment of hell is eternal separation from God, in whom alone man can possess the life and happiness for which he was created and for which he longs.
1036 The affirmations of Sacred Scripture and the teachings of the Church on the subject of hell are a call to the responsibility incumbent upon man to make use of his freedom in view of his eternal destiny. They are at the same time an urgent call to conversion: "Enter by the narrow gate; for the gate is wide and the way is easy, that leads to destruction, and those who enter by it are many. For the gate is narrow and the way is hard, that leads to life, and those who find it are few."618 [INDENT]Since we know neither the day nor the hour, we should follow the advice of the Lord and watch constantly so that, when the single course of our earthly life is completed, we may merit to enter with him into the marriage feast and be numbered among the blessed, and not, like the wicked and slothful servants, be ordered to depart into the eternal fire, into the outer darkness where "men will weep and gnash their teeth."619[/INDENT]