The Vatican announced July 14 the pope's appointment of the presidents-delegate: Cardinals Louis Sako of Baghdad, the Chaldean patriarch; Desire Tsarahazana of Toamasina, Madagascar; Charles Bo of Yangon, Myanmar; and John Ribat of Port Moresby, Papua New Guinea.

The synod will meet at the Vatican Oct. 3-28 to discuss "young people, faith and vocational discernment." As presidents-delegate, the cardinals will alternate presiding over the synod sessions.

The four cardinals come from areas in the world that reflect several major issues outlined in the synod's "instrumentum laboris" ("working document").

The working document emphasized the struggles of young Catholic men and women "who continue to live in situations of war or political instability" as well as those who suffer "discrimination and persecution to the point of martyrdom."

Cardinal Sako, who was ordained a bishop eight months after the U.S. invasion of Iraq, witnessed the persecution of native Christians and their subsequent exodus from the country.

After his installation as head of the Chaldean Catholic Church in 2013, the Iraqi prelate said the church must be a sign of hope, witness and communion, despite the difficulties, and work with all Iraqis to defend human dignity and peaceful coexistence based on equal rights.

The synod also will discuss the increasing number of young people living in precarious situations due to poverty, unemployment and marginalization, an issue that is familiar to Cardinal Tsarahazana, who hails from one of the world's poorest countries, with more than 90 percent of its population living below the $2-a-day poverty line.

Cardinals Sako and Tsarahazana were elevated to the College of Cardinals by Pope Francis June 28.

The synod's working document also underlines the requests by many young people for a church that works with "greater operational pragmatism" on key issues, including the protection of the environment.

Climate change is a key issue not only for the pope, but also for Cardinal Ribat, who has been outspoken about the effects that rising ocean levels have had on his people. Scientists attribute higher seas to melting polar ice as greenhouse gases from the burning of fossil fuels accumulate in the earth's atmosphere, causing the planet to warm.

The synod also will address the marginalization of young people who migrate with their families to other countries and are often victims of "different forms of racial or caste discrimination."

As Myanmar's first cardinal, Cardinal Bo joined with other religious leaders to promote peace and call for an end to persecution of ethnic minorities in the country, including the Rohingya, a minority Muslim group named the world's most persecuted people by the United Nations.