The day, Francis said, will give Catholics an opportunity to ask God's help in protecting creation and for forgiveness for "sins against the world."
At an audience with young people, the pontiff also spoke of his own greatest personal spiritual struggle and a recipe for living to 92.
The world continues to be silent in the face of widespread persecution of Christians and other religious minorities, Pope Francis said.
Ken Hackett, The U.S. ambassador to the Holy See believes Pope Francis is traveling to the United States to challenge the country's people to live up to their ideals.
Pope Francis ended his three-week summer vacation at the evening meeting and prayer Aug. 4 with some 9,000 altar servers.
Pope Francis has again strongly called on Catholic communities to have a welcoming and merciful attitude to Christians who have remarried outside the church after a divorce, saying that such people “are not by any means excommunicated” and should be made to feel a part of their communities.
Pope Francis said we must remember that feeling ashamed during confession is "a grace that prepares us for the embrace of the Father, who always forgives and always forgives everything."
More than a dozen individual celebrations will be scheduled for the Jubilee of Mercy in 2016, giving pilgrims the chance to celebrate their own holy year with Pope Francis in Rome.
The yearlong extraordinary jubilee will include a number of individual jubilee days, such as for consecrated men and women; deacons; priests; catechists; the sick and disabled; teenagers and prisoners. Young people will be able to celebrate their jubilee with the pope at World Youth Day in Krakow, Poland.
Through numerous speeches and homilies, Pope Francis has been offering concrete and, at times, colorful advice on the topic of family.
Helping to inaugurate an exhibit at the Vatican, the chief rabbi of Rome noted just how much "times have changed."
"Seeing in St. Peter's Square the banner announcing the exhibit with an image of a pope -- that's normal -- but a pope shaking hands with a rabbi? That's not normal. It's a sign of how times have changed," Rabbi Riccardo Di Segni said.
The banner shows the late St. John Paul II and the late Chief Rabbi Elio Toaff greeting each other in 1986 at Rome's main synagogue. John Paul was the first pope in modern history to enter a synagogue.