Zenit reports the move is to mark the 20th anniversary of the 1987 Montreal Protocol to protect the ozone layer of the Earth's atmosphere.
Addressing the faithful gathered in the courtyard of the papal summer residence at Castel Gandolfo, he urged "cooperation intensity" in the promotion of the common good.
The Holy Father said: "In the last two decades, thanks to exemplary collaboration between politicians, scientists and economists within the international community, important results have been obtained with positive repercussions on present and future generations.
But he expressed his desire to see cooperation intensify to ensure the "safeguarding of creation". He said the environment must be a "mirror of God the Creator".
Following the Vienna Convention of 1985, the Montreal Protocol established measures to control substances that threaten the ozone layer.
In a related story from the New York Times, the cardinals at the Vatican have accepted an unusual donation from a Hungarian group called Klimafa.
The company said it would plant trees to restore an ancient forest on a denuded stretch of land by the Tisza River, to offset the Vatican's carbon emissions. The young trees will be located on a 15-hectare tract to be renamed the Vatican Climate Forest.
Benedict XVI Pleads for Protection of Creation (Zenit, 17/9/07)
Vatican goes carbon-neutral (The Age, 18/9/07)
LINKS (not necessarily endorsed by Church Resources)
Montreal Protocol (Wikipedia)
Climate change, water of "utmost importance": Benedict insists (CathNews, 6/9/07)
Pope dons green vestments for Loreto eco-fest (CathNews, 3/9/07)
Pope gets top green rating (CathNews, 9/8/07)
Vacation pope answers questions - from 400 priests (CathNews, 26/7/07)
Vatican signs up for a carbon offset forest (CathNews, 13/7/07)
Worms tackle environment at Korean "Green Church" festival (CathNews, 8/6/07)
Vatican goes solar (CathNews, 28/5/07)
Green pope says save Amazon (CathNews, 14/5/07)