Across Europe, there is "a spreading ignorance about the Christian faith," which is exacerbated by the media "misinforming the public as to the content of our faith," the cardinal told the synod Monday.
Erdo, president of the Council of European Bishops' Conferences, was one of five speakers summarizing the state of evangelization in different regions of the world. Each of the five mentioned the role of the media, and several insisted on the church's obligation to use social networks to reach new generations of Catholics.
The Hungarian cardinal told the synod that Europeans are losing an awareness of just how essential Christianity has been to the development of their cultures, democracy and the human rights they hold so dear. The loss, he said, is a "consequence of an audiovisual culture" in which clear concepts and logical reasoning are ignored.
Mexican Archbishop Carlos Aguiar Retes of Tlalnepantla, president of the Latin American bishops' council, told the synod that since the Second Vatican Council, the Latin American bishops have focused on building community, entering into dialogue with the world around them and educating the faithful about their role in transforming society.
Today, he said, the church must "employ new communications technologies to allow the life and mission of the church to be known and for dialogue with the world." In today's culture, he said, "the social communications media are most influential."
In addition, Aguiar said, especially in trying to reach younger people, the church must "make use of social networks to spread Catholic thought and its current answers to cultural challenges."
Young people are searching for meaning in their lives, he said, and if the church is not present in their world with responses, they end up abandoning their search for God.
Indian Cardinal Oswald Gracias of Mumbai, president of the Federation of Asian Bishops' Conferences, told the synod that Asia is experiencing a boom in communications technology. "This is not to be viewed as a threat, but a great gift from God to be used to spread the good news."
The cardinal said the church must help parents, pastors and teachers who can train young people to use the new media and to benefit from them.
Archbishop John A. Dew of Wellington, New Zealand, president of the Federation of Catholic Bishops' Conferences of Oceania, told the synod that even the secular media have helped Catholic evangelization through the attention they have given the declaration of saints from the region.
The examples of local people formally recognized as saints by the universal church "will do more for the new evangelization that we can imagine as the media is interested and captures peoples' imagination," the archbishop said.
If the church wants to find young people, he said, it must use the new media and new gadgets they use.
"In these young people we see a sincere and sometimes painful search for meaning and spirituality as they bridge traditional cultural values and the excitement of the technological age with the swipe of an iPad or smartphone."
In addition to looking at the media, the regional reports to the synod touched on almost every area of church life from the importance of the liturgy to the positive impact of immigration, and from the role of new lay movements to the need to support traditional families.
Tanzanian Cardinal Polycarp Pengo of Dar es Salaam, president of the Symposium of Episcopal Conferences of Africa and Madagascar, said the rise of Islamic fundamentalism in Africa is a challenge to the work of the church on the continent.
Catholics must "face the difficulty of dialoguing with the vast majority of good Muslims who, however, are mute, and the small groups of fundamentalists," who are not open to dialogue.
Dialogue also was a key topic in the other regional reports.
Gracias said with Christians making up only 3 percent of the population in Asia and with persecution of Christians not being completely uncommon, "for us in Asia, dialogue is a necessity, not a luxury."
At the same time, he said, many Asian cultures have a deep respect for life -- including for the life of animals and plants -- and it should not be difficult, through dialogue, to help people see that respect for life must include the life of the unborn and the life of their neighbors who belong to a different faith.
Erdo said while "some new (Christian) communities are strongly anti-Catholic," dialogue and cooperation with the Orthodox and Protestant communities is growing. Particularly with the Orthodox, he said, there are joint efforts to address moral and social questions, to protect the traditional family and to defend human life.
Aguiar said that dialogue is increasingly important in Latin America as its cultures become more pluralistic.
The church's dialogue efforts, he said, must reach out to all sectors of society to share the church's position on issues such as human dignity, and to find ways to build a consensus on how to tackle problems related to education, the economy, migration, justice and peace and the need to protect the environment.
The archbishop agreed with other speakers that Catholics must learn the content of their faith from the Catechism of the Catholic Church, but he insisted they also must know Catholic social teaching because they have an obligation to transform society in line with Gospel values.