Pope Benedict has led the Catholic Church's first 'eco-friendly' youth rally at the weekend, telling half a million people that world leaders must make courageous decisions to save the planet "before it is too late".

The Pope added: "A decisive 'yes' is needed in decisions to safeguard creation as well as a strong commitment to reverse tendencies that risk leading to irreversible situations of degradation."

He addressed a huge crowd of mostly young people over a hillside near the Adriatic city of Loreto as the Church marked its annual 'Save Creation Day'.

More than 300,000 people slept on blankets and in tents or prayed during the night, reports Reuters.

Organisers said they were also joined by approximately 200,000 more who arrived from throughout Italy yesterday.

Pope Benedict said: "New generations will be entrusted with the future of the planet, which bears clear signs of a type of development that has not always protected nature's delicate equilibriums."

He continued: "Courageous choices that can re-create a strong alliance between man and earth must be made before it is too late."

It was the first environmentally friendly youth rally, which saw attendees use backpacks made of recyclable material, flashlights operated by a crank instead of batteries, and colour-coded trash bags so personal garbage could be easily recycled. Throughout the event, meals were also served on biodegradable plates.

Tens of thousands of prayer books for the closing Sunday mass were printed on recycled paper and the Catholic Church has said that an adequate number of trees will be planted to compensate for the carbon produced at the event.

Pope Benedict voiced concern about a breakdown of the traditional family and in his Sunday homily told young people to "go against the current" and challenge "seductive" media messages promoting materialism, consumerism and temporary pleasures.