Speaking to a massive group of young Catholics in Sydney on Thursday, with the Australian city's spectacular backdrop behind him, Pope Benedict XVI gave a stern warning about the planet's health.
Earth is suffering from "erosion, deforestation, the squandering of the world's mineral and ocean resources, in order to fuel an insatiable consumption," he told more than 200,000 pilgrims gathered for World Youth Day.
He called on those in attendance to be better stewards of the environment, noting that the effects of climate change are dramatic and severe.
"Some of you come from island nations whose very existence is threatened by rising water levels; others from nations suffering the effects of devastating drought," Benedict said.
The Pope also called on young Catholics to embrace principles of peace and said such a shift, along with a greater sense of environmental responsibility, will be essential for the future of humanity.
He also listed substance abuse, sexual degradation linked to TV and the Internet and the exaltation of violence as afflictions that are poisoning the world's social environment.
Benedict -- who was greeted by Aboriginal dancers on his arrival -- was speaking on a disused wharf in Sydney as the massive six-day Roman Catholic festival opened.
During his speech -- the first major appearance of his 10-day visit -- Benedict gave credit to Australian Prime Minister Kevin Rudd for making a formal apology to Aboriginals for their past treatment at the hands of the Australian government.
Indigenous Aboriginals in Australia are the country's poorest minority. They have some of the highest rates of poverty, illiteracy and alcohol abuse in the country.
Rudd made the apology shortly after taking office in February.
Kris Dmytrenko of Salt and Light Television, the only Canadian journalist to have met the Pope on this trip, said while the pontiff has touched on a number of issues already, he is focused on young people.
"It must be said that his primary reason for being here in Australia is to celebrate with the young people and to celebrate their accomplishments and to celebrate their faith, although (the Aboriginal) issue is bound to come up," Dmytrenko told CTV's Canada AM, speaking from Sydney.
Another Canadian, Anita Stante, said she was one of the pilgrims who had the opportunity to get close to the Pope.
Stante, who is on a team helping to prepare liturgy for the event, told Canada AM she was within 10 metres of the pontiff and found his presence to be inspiring.
"He had a lot of faith in us young people and he was really encouraging us to strive for truth," she said.
