"Across the globe, 175 million migrants seek safety and sustenance in an unknown land," Bishop John C. Wester of Salt Lake City told the Vatican-sponsored World Congress for the Pastoral Care of Migrants.

Those who move looking for a better life for themselves and their families, as well as those forced to flee violence, persecution and war share hopes for a better future and the pain of separation from loved ones and familiar places, he said Nov. 18.

Migrant parents worry about keeping their children fed, housed, healthy and finding schools for them, Bishop Wester said. "Spouses separated by migration struggle to maintain their families, and children endure feelings of abandonment, alienation and often insecurity due to their separation from parents," even when their parents are moving abroad specifically to provide a better future for their children.

Currently in the United States, the bishop told the congress, the "most pressing family-related immigration concern of the moment" is the "alarming growth in the number of unaccompanied minors and families from Guatemala, Honduras, El Salvador and Mexico seeking safety in the United States."

From 2004 to 2011, he said, "the average number of children arriving to the U.S. alone was 6,800. In 2012, the number was over 13,000. In 2013, it nearly doubled to 24,000. By August of this year, the number was 53,000, with several thousand more expected by the end of the year."

"Though the number is growing, the children can and should be easily cared for in the richest country in the world," he said.

"The sheer desperation of parents represented by the numbers" is alarming, Bishop Wester said. A delegation of U.S. bishops who visited the Central American countries found "a perfect storm" of root causes: lack of economic opportunities, lack of educational facilities, escalating violence and the inability of the governments to protect their people.

The U.S. bishops, he said, are trying to educate Catholics and others "on the causes of flight and move them to respond in a compassionate way."

"The picture for immigrants can be bleak, but we are a church of hope and action," Bishop Wester said. "The arrival of unaccompanied children and families is a test for our country, the United States," to see if it can counter what Pope Francis has described as "the globalization of indifference and the throwaway culture of our world."

"As an immigrant nation and an immigrant church," he said, the Catholic Church in the United States is obliged "to set an example to the world and demonstrate our solidarity with migrants."

Philippine Cardinal Luis Antonio Tagle of Manila spoke to the congress about the ways migrants become bridges between their country of origin and their countries of destination, a daily experience for for millions of Filipinos working overseas.

The idea of "diaspora" -- living outside one's ancestral home but maintaining ties at least culturally, if not personally -- is a concept "filled with images and stories of pain" of people separated from their families and often experiencing rejection in a new land, the cardinal said.

But the reality also has a positive side, one of potential to create bridges between countries and cultures through the migrants, he said.

Catholics and people of good will are called to shift their perspective and stop viewing and speaking of migration simply as a problem, he said.

"Our creativity, optimism and solidarity with migrants could direct the narrative, the story of pain and humiliation" and turn it into "the experience of resurrection and renewed mission," Cardinal Tagle said.

Part of the key to making that shift, he said, is to realize that all people are temporary guests, strangers, on this earth, and to realize that in a church that claims to be catholic or universal, everyone must be made to feel at home.

The Filipino overseas workers and migrant groups from other predominantly Catholic countries are filling and reviving Catholic parishes in countries where attendance has fallen, he said. They are witnesses to a living faith.

"We say this not with pride, but with holy pride," he added.

In addition, the cardinal said, "by ministering to migrants in the diasporas, the church challenges the system of social and economic inequality, ethnic, political and religious conflicts, and ecological degradation that force many people to migrate, leave their countries of origin."

The Catholic Church, he said, is called to challenge "policies that are inhuman and unreasonably restrictive to migrants, preventing them from being dignified and productive" in a new land.

"It causes Christians a lot of pain to see some governments win -- gain votes -- with an explicitly anti-migrant policy," he said.