From the editor’s desk

Green thoughts in a green city

With his organic garden at Highgrove House and his regular comments about the environment, the Prince of Wales has long been an advocate of green causes. So it came as no surprise that he raised the plight of the planet at his meeting with Pope Benedict XVI at the Vatican this week. The world risked "a new Dark Age", said Prince Charles, unless urgent action is taken on climate change.

He was preaching to the converted. Pope Benedict has increasingly turned his attention to the environment. During an address for World Peace Day in 2006, he said: "The destruction of the environment, its improper or selfish use and the violent hoarding of the earth's resources cause grievances, conflicts and wars, precisely because they are the consequences of an inhumane concept of development." In December his annual holiday address to the Roman Curia made headlines around the world for his comments on the traditional family, but it also included a little-noticed commitment to the protection of the tropical rainforests.

The Vatican is putting its money where its theology is and is aiming to be carbon neutral. It has invested in solar panels on the roof of the Paul VI Auditorium, and is installing a solar-heating system for its staff cafeteria. Its most ambitious plan to date is to build the biggest solar plant in Europe for 500 million euros near the medieval village of Santa Maria di Galeria, providing enough energy to power 40,000 households. Cardinal Giovanni Lajolo, in charge of Vatican City State, recently told the Bloomberg news agency that it will bring "incomparable rewards". This is clearly not just about money, although the Vatican will be able to sell its excess solar energy. Last year, Bishop Gianfranco Girotti, head of the Apostolic Penitentiary, warned that damaging the planet was a social sin, on a par with the more traditional personal vices. "You offend God not only by stealing, taking the Lord's name in vain or coveting your neighbour's wife but also by wrecking the environment," he said.

The Catholic Church's thinking on the environment has developed in recent years through a theology of stewardship, increasingly understanding that with dominion over the earth went responsibility for its wellbeing. God did not hand the planet over for it to be abused. An even greater influence on its thinking about green issues has emerged out of its commitment to justice and peace. As the climate changes, those in the poorest parts of the world are being most affected, with their homes and livelihoods put at risk by increased flooding, drought and alterations to the seasons.

During his visit to the Vatican, Prince Charles said that the global economic crisis is nothing compared with the horror of global warming. Pope Benedict is clearly taking the economic crisis very seriously and his long-awaited social encyclical is said to have been delayed by his desire to understand the causes and consequences of the crisis as fully as possible, although he has already clearly intimated that he believes greed is at the root of the problem. He may conclude the same about the threat to the environment. The encyclical is an opportunity for him to expand further on these linked themes. Catholic social teaching is in need of an update in this area. The Green Pope is the theologian to do it.