Pope Benedict XVI denounced the failure of world leaders to agree to a new climate change treaty in Copenhagen last month, saying Monday that world peace depends on safeguarding God's creation, the Associated Press reports.

He issued the admonition in a speech to ambassadors accredited to the Vatican, an annual appointment during which the pontiff reflects on issues the Vatican wants to highlight to the diplomatic corps, AP reporter Nicole Winfield writes.

Benedict has been dubbed the "green pope" for his increasingly vocal concern about protect the environment, an issue he has reflected on in encyclicals, during foreign trips and most recently in his annual peace message. Under Benedict's watch, the Vatican has installed photovoltaic cells on its main auditorium to convert sunlight into electricity and has joined a reforestation project aimed at offsetting its CO2 emissions.

For the pontiff, it's a moral issue: Church teaching holds that man must respect creation because it's destined for the benefit of humanity's future.

In his speech, the pontiff criticized the "economic and political resistance" to fighting environmental degradation that was exemplified in the negotiations to draft a new climate treaty at last month's summit in Copenhagen.