Tension between conservative and liberal Catholics in the United States over Pope Francis’ perceived tolerance for gays and lesbians and the divorced has entered a new arena of conflict: Climate change and the environment.

That tension has boiled over in recent days as Pope Francis readies a papal encyclical on the environment, and amid reports that he may use an expected September address at the United Nations to address the polarizing issue of global warming.

“He is an ideologue and a meddlesome egoist,” Maureen Mullarkey wrote of Pope Francis at First Things, a conservative journal that also covers Catholic issues. “His clumsy intrusion into the Middle East and covert collusion with Obama over Cuba makes that clear. Megalomania sends him galloping into geopolitical — and now meteorological — thickets, sacralizing politics and bending theology to premature, intemperate policy endorsements.”

Thomas Peters, a writer for Catholic Vote who led young adults in fighting same-sex marriage, criticized the pope’s anticipated speech at the UN, citing its programs and policies at odds with Catholic teaching; specifically, population control and abortion.

“Again, preservation of the environment and promotion of sustainable development? No problem,” he wrote recently. “But climate change and the blundering, malicious environment of the UN? No thanks. The pope can do better.”

Bishop Marcelo Sánchez Sorondo, chancellor of the Pontifical Academy of Sciences, said in November that after Francis releases his encyclical, he plans to convene a meeting of faith leaders on the issue before two crucial summits on the environment: a meeting in September at the United Nations to draft Sustainable Development Goals and another gathering on climate change in Paris in December.

However, Francis is not the first pope to tackle environmental issues, and not even the first to address climate change directly.

His predecessor, Pope Benedict XVI, took steps to make the Vatican the first fully carbon-neutral state by installing solar panels and buying carbon offsets. The panels reduce the need for the Vatican to burn fossil fuels, the major source of so-called greenhouse gases that scientists say trap heat in the atmosphere. Buying carbon offsets, or credits, funds projects that reduce carbon emissions.

In his World Day of Peace message in 2010, the retired pope specifically cited climate change as a threat to “human rights, such as the right to life, food, health, and development.”

“Can we remain indifferent,” he asked, “before the problems associated with such realities as climate change, desertification, the deterioration and loss of productivity in vast agricultural areas, the pollution of rivers and aquifers, the loss of biodiversity, the increase of natural catastrophes, and the deforestation of equatorial and tropical regions?”

He also voiced support for the UN Climate Change Conference in Durban, South Africa, in 2011, urging participants to “reach agreement on a responsible, credible response” to climate change.

Before that, Pope John Paul II wrote about an “ecological crisis” in 1990, and in 1971, Pope Paul VI called environmental degrading “a wide-ranging social problem” that risks turning humanity into “the victim of this degradation.”

In the United States, Catholic bishops released a statement on climate change in 2001, in which they said “the United States bears a special responsibility in its stewardship of God’s creation to shape responses that serve the entire human family.”

Rhett Engelking, who works with young adults on environmental issues for the Franciscan Action Network, said that continuity on this issue is important.

“John Paul II talked about what was needed when he asked everybody to have an ecological conversion, and Benedict really laid the groundwork of why something like that could happen,” he told Crux. “What we’re really hoping is that Francis will show people how to take action and embody the ongoing ecological conversion.”

Like the general population, Catholics in the United States are split on the issue of climate change.

A 2014 survey by the Public Religion Research Group found that a majority of white Catholics (60 percent) in the United States are either “somewhat unconcerned” or “very unconcerned” with climate change. However, nearly three-quarters of Hispanic Catholics are either “very concerned” or “somewhat concerned,” well above the 50 percent of all Americans who share those beliefs.

Kishore Jayabalan, director of the Rome office of the Acton Institute, said that although he would welcome an encyclical on environmentalism, he hopes it steers clear of climate change, which he said is up for debate.

“If it gets more into the scientific and policy aspects of it, it’s probably going to be less helpful for the Church as a whole, and it would probably please one side of the political spectrum and anger the other, and really show it to be a document quite limited by time and place,” he told Crux.

Some well-known climate change skeptics also are slamming the pope’s involvement.

“The global warming narrative has weakened, and to now have a pope jump on that bandwagon would sow confusion, I think, among Catholics,” said Marc Morano, a climate change skeptic, on Fox News.

Fox News correspondent Doug McKelway said in the same report that the encyclical could align the pope with “environmental extremists who favor widespread popular control and wealth redistribution, an alignment that may test the faith of some Catholics.”

Engelking, the Franciscan organizer, dismisses that concern.

“One of the benefits we have in Franciscan theology is a horizontal view of creation, that we are as dependent on the environment and the Earth as the Earth is dependent upon us,” he said. “Some people want human beings to be on top, have dominion and everything, but it’s more complicated than that.”

What will be included in the forthcoming encyclical remains anyone’s guess, but a letter from the pope to scientists who gathered in Lima last month, and a United Nations speech by his chief diplomat in September, both offer clues.

“The time to find global solutions is running out. We can find adequate solutions only if we act together and unanimously,” Francis said in a written message to Manuel Pulgar-Vidal, Peru’s minister of the environment and host president of the 20th UN Climate Change Conference.

The pope encouraged the leaders in their discussions, he said, because their decisions will “affect all of humanity, especially the poorest and future generations. What’s more, it represents a serious ethical and moral responsibility.”

The impact climate change already has had on coastal regions and other areas “reminds us of the seriousness of negligence and inaction,” the pope said. “It is morally imperative that people act.”

“An effective fight against global warming will be possible only with a collective and responsible answer” that overcomes one-sided or special interests and is “free from political and economic influence,” he said.

At the United Nations, describing evidence of global warming as “unequivocal,” Cardinal Pietro Parolin said climate change “has grave consequences for the most vulnerable sectors of society and, clearly, for future generations.”

Parolin, the Holy See’s secretary of state, said “an authentic cultural shift is needed which reinforces our formative and educational efforts, above all in favor of the young, towards assuming a sense of responsibility for creation and integral human development of all people, present and future.”

Dan Misleh, executive director of the Catholic Climate Covenant, said the pope’s encyclical could help bring about that shift. He said he hopes the document will help Catholics “get our own spiritual house in order.”

“I’m hoping that [the encyclical] helps people realize that we have these very ancient traditions that go back to Genesis,” he told Crux. “Through the centuries, we’ve sort of forgotten that, because we now are able to isolate ourselves from creation and we don’t have the same appreciation we once did. We just need to recover that teaching and apply it to that new situation of environmental degradation and climate change.”

Jayabalan, at the Acton Institute, said the pope should get involved in the climate debate only if he has a unique perspective, which he doubts Francis has, given the numbers of policy experts and scientists involved in the debate.

“Does he have anything particular to contribute to the climate change debate? I think is the first question,” he said. “If he does, it ought to be something that no other political leader, no other scientist, really says.”

Rather, the pope should stick to moral and theological issues, Jayabalan said, pointing to Pope Francis’ work on human trafficking and even Pope Benedict’s talk on the environment, which he said started with “a theological perspective, from an understanding of what God wants from us in terms of stewardship.”

The Catholic Climate Covenant’s Misleh, however, said that Pope Francis has spoken “a little bit more bluntly about some of these issues,” leading to strong reaction from his critics.

“He understands all of these issues, and he certainly is not aligning himself with groups that would oppose core principles of Catholic social teaching. He’s aligning himself with the Gospel,” he told Crux. “The fact that there are these preemptive attacks on the encyclical, without having read the encyclical, seems to me to be a little bit over the top.”

Material from the Catholic News Service was used in this report.