Pope Francis challenged world leaders on October 4 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 update to his landmark 2015 encyclical on the environment, Pope 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,” Pope 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.

Using precise scientific data, sharp diplomatic arguments and a sprinkling of theological reasoning, Pope 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.

As it is, Pope’s 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, Pope 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, Pope 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.

“Small changes can cause greater ones, unforeseen and perhaps already irreversible, due to factors of inertia,” he noted. “This would end up precipitating a cascade of events having a snowball effect. In such cases, it is always too late, since no intervention will be able to halt a process once begun.”

“Praise God,” was issued ahead of the next round of U.N. climate talks which begin November 30 in Dubai. Just as he did with his 2015 encyclical “Praise Be,” which was penned before the start of the Paris climate conference, Pope 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 two degrees Celsius (3.6 degrees Fahrenheit) since pre-industrial times. It’s already warmed about 1.1 degrees (two degrees Fahrenheit) since the mid-1800s.

Pope said that it was clear that the Paris target will be breached and will soon reach three degrees Celsius, and that already the effects are obvious, with oceans warming, glaciers melting and the world registering record heat waves and extreme weather events.

“Even if we do not reach this point of no return, it is certain that the consequences would be disastrous and precipitous measures would have to be taken, at enormous cost and with grave and intolerable economic and social effects,” he warned.

Since 2015, the world has spewed at least 288 billion metric tonnes (317 billion U.S. tonnes) 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 tonnes (2,300 billion U.S. tonnes) 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. Pope concluded his document by noting the emissions rate in the U.S. and shaming it to do better.

“’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.