Pope Francis called the destruction of the environment “an offense against God” in a message given to the participants in the U.N. climate summit on Saturday.

The keynote address that the pope had intended to give in person at the COP28 conference was distributed to the attendees in Dubai, where Vatican Secretary of State Cardinal Pietro Parolin read a shortened version of the pope’s speech to the assembly on Dec. 2.

Pope Francis, who turns 87 in two weeks, canceled his scheduled trip to the United Arab Emirates days before the climate summit at the request of his doctors after coming down with a flu infection that left him with breathing difficulties and acute bronchitis.

“Sadly, I am unable to be present with you, as I had greatly desired,” the pope said in his message to COP28.

“Even so … I am with you because the destruction of the environment is an offense against God, a sin that is not only personal but also structural, one that greatly endangers all human beings, especially the most vulnerable in our midst, and threatens to unleash a conflict between generations.”

Pope Francis would have been the first pope to attend the U.N.’s climate change conference, known as the “Conference of the Parties” (COP), which has been held annually since 1995.

Care for creation has been an important theme in Francis’ pontificate. The pope has said that he decided to write his 2015 environmental encyclical Laudato Si’ ahead of the COP21 summit in Paris and recently published a new apostolic exhortation titled Laudate Deum (“Praise God”), called climate change “one of the principal challenges facing society and the global community.”

In his message to the COP28 conference, the pope underlined the need for “multilateralism” to establish “global and effective rules” to fight climate change.

“Climate change signals the need for political change. Let us emerge from the narrowness of self-interest and nationalism; these are approaches belonging to the past,” he said.

The pope called it “disturbing” that “global warming has been accompanied by a general cooling of multilateralism, a growing lack of trust within the international community.”

“How much energy is humanity wasting on numerous wars … conflicts that will not solve problems but only increase them!” he added.

Pope Francis described environmental protections as part of “a culture of life” and underlined that attempts to shift blame for climate change onto the poor or high birth rates “must be firmly dispelled.”

“Births are not a problem, but a resource: They are not opposed to life, but for life, whereas certain ideological and utilitarian models now being imposed with a velvet glove on families and peoples constitute real forms of colonization,” he said.

“Let us join in embracing an alternative vision: this will help to bring about an ecological conversion, for ‘there are no lasting changes without cultural changes’ (Laudate Deum, 70),” the pope added.

“In this regard, I would assure you of the commitment and support of the Catholic Church, which is deeply engaged in the work of education and of encouraging participation by all, as well as in promoting sound lifestyles, since all are responsible and the contribution of each is fundamental.”

During the COP28 summit in Dubai, Cardinal Parolin will also preside over the inauguration of an interfaith pavilion at the climate conference on Dec. 3 alongside Spanish Cardinal Miguel Ángel Ayuso Guixot, an expert on Islam and current prefect of the Dicastery for Interreligious Dialogue.

The faith pavilion, hosted by the Muslim Council of Elders, will serve as a hub for faith-based engagement on climate issues and as the venue for more than 65 sessions with religious figures, scientists, and political leaders at the conference.