The archbishop of Canterbury, Rowan Williams, has urged the public not to give up on young people in his new year address, despite the "horrific" scenes witnessed during the riots last summer. Describing the violence as "angry" and "lawless", he said young people can "flourish" when shown the right support and love.

"Quite a lot of the images we're likely to remember from the footage of the riots in the summer will be of young people out of control on the streets, walking off with looted property from shops, noisily confronting police and so on," he said.

"It feeds into the national habit of being suspicious and hostile when we see groups of youngsters on street corners or outside shops and bus shelters. We walk a bit more quickly and hope we can pass without some sort of confrontation. The events of the summer were certainly horrific. They showed us a face of our society we don't like to think about – angry, destructive, lawless," he said.

But those involved were a minority, and most young people shared the "general feeling of dismay at this behaviour", he added.

Praising charities such as Kids Company in south London and the Children's Society, he said: "When you see the gifts they can offer, the energy that can be released when they feel safe and loved, you see what a tragedy we so often allow to happen."

Calling on people to recognise how their actions can help improve society as a whole, he said: "Being grown up doesn't mean forgetting about the young.

"And a good new year's resolution might be to think what you can do locally to support facilities for young people, to support opportunities for counselling and learning, and enjoying a safe environment."

The theme of Pope Benedict's address on the Roman Catholic church's annual World Day of Peace also focused on educating and supporting young people. Benedict, 84, marked his seventh new year as pope by saying humanity faces a challenge – educating new generations in justice and peace in order to avoid the violent tragedies of the past.

Celebrating mass for several thousand people in St Peter's, he said it was a task for every generation following the two world wars in the 20th century and other conflicts since.

Educating the young "in knowledge of the truth, in fundamental values and virtues, is to look to the future with hope," he said in his homily.

Young people needed all-round education, and this required a social commitment to justice and peace, the leader of the world's 1.3 billion Roman Catholics said. They must use advances in communications technology to promote peaceful coexistence, mutual respect, dialogue and understanding.

"Young people ... are open to these attitudes but the social reality in which they grow up can lead them to think and act in the opposite way, even to be intolerant and violent," he said.

As usual at papal events since October the pope, who is believed to have arthritis in the legs, was wheeled up the central aisle of St Peter's standing on a mobile platform.

The Vatican says this is to save his strength, allow more people to see him and prevent attacks like the one on Christmas Eve 2009, when a woman lunged at him and knocked him to the ground.