Pope Francis shamed and challenged world leaders on Wednesday to commit to binding targets to slow climate change before it’s too late, warning that God’s increasingly warming creation is fast reaching a “point of no return.”

In an unusually bleak update to his landmark 2015 encyclical on the environment, Francis heightened the alarm about the “irreversible” harm to people and planet already under way and lamented that once again, the world’s poor and most vulnerable are paying the highest price.

“We are now unable to halt the enormous damage we have caused. We barely have time to prevent even more tragic damage,” Francis warned.

He took square aim at the United States, noting that per-capita emissions in the U.S. are twice as high as China and seven times greater than the average in poor countries. While individual, household efforts are helping, “we can state that a broad change in the irresponsible lifestyle connected with the Western model would have a significant long-term impact,” he said.

The document, “Praise God,” was released on the feast of St. Francis of Assisi, the pontiff’s nature-loving namesake, and was aimed at spurring negotiators to commit to binding climate targets at the next round of U.N. talks in Dubai.

Francis weighed in on a key and contentious point of negotiations — whether countries should agree to a phase out of coal, oil and natural gas, the fossil fuels that are causing climate change. He is for it. As fast as possible even, he wrote.

Using precise scientific data, sharp diplomatic arguments and a sprinkling of theological reasoning, Francis delivered a moral imperative for the world to transition away from fossil fuels to clean energy with measures that that are “efficient, obligatory and readily monitored.”

“What is being asked of us is nothing other than a certain responsibility for the legacy we will leave behind, once we pass from this world,” he said.

U.S. climate scientist Carlos Martinez, a committed Catholic who heads a multifaith committee for the American Meteorological Society, said it reads like a report card for Earth and its people and “it appears from the language that he would give students a D, like a D-. Because there has been some progress, but it’s not where it needs to be.”

“He does not mince his words as to the state of the environment and its impacts to people and to communities,” Martinez said.

This is one of the least hopeful messages that Pope Francis has issued, Martinez said. But it is scientifically accurate, he and other scientists told The Associated Press.

“The tone is appropriate given the magnitude of the challenges we face,” Northern Illinois University climate scientist Victor Gensini said.

As it is, Francis’ 2015 encyclical “Praise Be” was a watershed moment for the Catholic Church, the first time a pope had used one of his most authoritative teaching documents to recast the climate debate in moral terms.

In that text, which has been cited by presidents, patriarchs and premiers and spurred an activist movement in the the church, Francis called for a bold cultural revolution to correct a “structurally perverse” economic system where the rich exploit the poor, turning Earth into an “immense pile of filth.”

Even though encyclicals are meant to stand the test of time, Francis said he felt an update to his original was necessary because “our responses have not been adequate, while the world in which we live is collapsing and may be nearing the breaking point.”

He excoriated people, including those in the church, who doubt mainstream climate science about heat-trapping greenhouse gas emissions, sarcastically deflating their arguments and showing his impatience with their profit-at-all-cost mentality.

Shaming them for their reliance on “allegedly solid scientific data,” he said the doubters’ arguments about potential job losses from a clean energy transition were bunk. And he cited data showing that increased emissions and the corresponding rise in global temperatures have accelerated since the Industrial Revolution, and particularly in the last 50 years.

“It is no longer possible to doubt the human – ‘anthropic’ – origin of climate change,” he asserted.

While acknowledging that “certain apocalyptic diagnoses” may not be grounded, he said inaction is no longer an option. The devastation is already under way, he said, including with some already “irreversible” harm done to biodiversity and species loss that will only snowball unless urgent action is taken now.

The document was unusual for a papal exhortation and read more like a U.N. scientific report or a speech to a “Fridays for Future” youth climate rally. It carried a sharp, no holds barred tone and its footnotes had far more references to U.N. climate reports, NASA and Francis’ own previous encyclicals than Scripture.

“To have a global religious leader like Pope Francis putting climate action in terms of defending life is huge,” said Evangelical Environmental Network President Jessica Moerman, a climate scientist turned pastor and board member of the National Association of Evangelicals. This, she said, is telling people that climate change “is causing human suffering and that as people of faith committed to defending life, this is something we can no longer ignore.”

“Praise God,” was issued ahead of the next round of U.N. climate talks which begin Nov. 30 in Dubai. Just as he did with his 2015 encyclical “Praise Be,” which was penned before the start of the Paris climate conference, Francis aimed to cast the issue of global warming in stark moral terms to spur courageous decisions by world leaders.

In the 2015 landmark Paris Agreement, countries of the world agreed to try to limit warming to 1.5 degrees Celsius (2.7 degrees Fahrenheit) or at least 2 degrees Celsius (3.6 degrees Fahrenheit) since pre-industrial times. It’s already warmed about 1.1 degrees (2 degrees Fahrenheit) since the mid-1800s.

Since 2015, the world has spewed at least 288 billion metric tons (317 billion U.S. tons) of heat-trapping carbon dioxide in the air, not including this year’s emissions, according to the scientists at Global Carbon Project. In August 2015, there were 399 parts per million of carbon dioxide in the air and in August 2023 it was up to 420 parts per million, a 5% jump.

The record-hot summer of 2023 is one-third of a degree Celsius (six-tenths of a degree Fahrenheit) warmer than the summer of 2015, according to the U.S. National Oceanic and Atmospheric Administration. Antarctica and Greenland have lost more than 2,100 billion metric tons (2,300 billion U.S. tons) of land ice, since the summer of 2015, according to NASA.

And in the United States alone, there have been 152 climate or weather disasters that caused at least $1 billion in damage since the pope’s first climate message, with costs adjusted for inflation, according to NOAA.

Francis devoted an entire section of his document on upcoming climate negotiations in Dubai, saying a switch in the way the world gets its energy has to be “drastic, intense and count on the commitment of all.”

“‘Praise God’ is the title of this letter. “For when human beings claim to take God’s place, they become their own worst enemies,” he wrote.