As Pope Benedict again called on young people to defend nature from a "correct ecological perspective", the first solar panels have been installed on the Paul VI auditorium at the Vatican.
BBC News reports Pope Benedict has become the first pontiff to harness solar power to provide energy for the Vatican.
Roof tiles on the Paul VI auditorium, used in poor weather for the Pope's weekly audience with pilgrims, are being replaced by 2,700 solar panels.
The photovoltaic cells will convert sunlight into electricity, generating enough power to light, heat or cool the 6,000 seat hall, engineers say.
Working beneath a brilliantly clear Roman sky on Monday, a group of engineers in yellow T-shirts positioned the dark cells on the auditorium's roof.
The solar panels are replacing deteriorating cement roof tiles.
Andre Koekenhoff, one of the workers, said the initiative was an attempt to make the Vatican "a little bit greener".
"With this plant, if it is working, in about two weeks we avoid 200 tonnes of carbon dioxide, and this is the equivalent to 70 tonnes of oil," he told the Associated Press news agency.
When the hall is not in use, the surplus energy produced will reportedly be fed into the Vatican's power network.
The Paul VI auditorium was designed by architect Pier Luigi Nervi and built in 1969, but the cement panels on its roof were deteriorating and it was decided last year to replace them with solar panels.
The panels, reportedly worth $1.5m, were donated as a gift to the German born Pope by a Bonn-based company, Solar World, AP reported.
Vatican Climate Forest
Meanwhile, L'Osservatore Romano reports the first saplings of the Vatican Climate Forest, a reforestation project to offset the Vatican's carbon dioxide emissions, will be planted in November, Catholic News Service notes.
The US based Planktos Inc and its Hungarian partner, KlimaFa Ltd, are restoring more than 600 acres of forests in Hungary along the Tisza River to offset emissions of carbon dioxide, or CO2.
The two companies earn money by selling greenhouse gas mitigation credits to individuals and businesses. Whatever carbon dioxide emissions an individual or company cannot eliminate can be offset by planting trees or buying the carbon mitigation credits of a company that plants trees or takes other action to eliminate carbon dioxide from the atmosphere.
Planktos and KlimaFa announced in 2007 that they would donate to the Vatican enough mitigation credits to offset the Vatican's annual CO2 production, estimated at 10,000 tons.
The monetary value of the gift is almost $250,000, said L'Osservatore Romano, the Vatican newspaper.
The paper reported on September 28 that the planting of 125,600 oak, white willow, black poplar and wild fruit trees would begin in November after the existing trees in the area have finished losing their leaves and before the ground begins to freeze.
A 20 year management project is planned for the forest, which will become a permanent part of the Hungarian national forest system, the newspaper said.
The project, the paper said, deals only with compensating for the greenhouse gases emitted by heating and cooling Vatican buildings and driving Vatican cars.
"To fight pollution effectively, therefore, other kinds of interventions are necessary to save energy, reduce harmful emissions and use renewable energy," the paper said.
Tourism must be environmental: Pope
And in a message for World Tourism Day 2008, Pope Benedict pointed out that humanity has the duty to protect the resources of creation and "to commit itself against the indiscriminate use of the goods of the earth", because "without adequate ethical and moral limits, human behaviour can become a threat and a challenge.
"Experience shows that the responsible administration of creation is part, or should be part, of a healthy and sustainable tourist economy", Pope Benedict added.
"It is therefore necessary, especially in the field of tourism which depends so heavily on nature, that everyone should seek a well-balanced management of our habitat, in what is our common home. ... Environmental degradation can be stopped only by spreading an appropriate culture which includes more sober lifestyles. ... Hence the importance of educating people to an 'ethic of responsibility'".
The Holy Father told his audience that the Church shared their commitment "to what is known as social tourism, which promotes the participation of the weaker sectors of society and thus can be an important tool in the fight against poverty, ... creating work, protecting resources and promoting equality". Social tourism "represents a reason for hope in a world where differences between those who have everything and those who suffer hunger, want and drought have become more accentuated."
Finally, the Pope called on young people "to support and practice ways of behaviour that help to appreciate and defend nature from a correct ecological perspective, as I highlighted on a number of occasions during World Youth Day in Sydney in July."