Pope Francis has declared a global “climate emergency”, warning of the dangers of global heating and that a failure to act urgently to reduce greenhouse gases would be “a brutal act of injustice toward the poor and future generations”.

He also endorsed the 1.5C limit on temperature rises that some countries are now aiming for, referring to warnings from the Intergovernmental Panel on Climate Change of “catastrophic” effects if we crossed such a threshold. He said a “radical energy transition” would be needed to stay within that limit, and urged young people and businesses to take a leading role.

“Future generations stand to inherit a greatly spoiled world. Our children and grandchildren should not have to pay the cost of our generation’s irresponsibility,” he said, in his strongest and most direct intervention yet on the climate crisis. “Indeed, as is becoming increasingly clear, young people are calling for a change.”

The Pope’s impassioned plea came as he met the leaders of some of the world’s biggest multinational oil companies in the Vatican on Friday to impress upon them the urgency and scale of the challenge, and their central role in tackling the emissions crisis. It followed a similar meeting last year, but this time the Pope’s stance was tougher as he warned that time was running out and urged them to hear “the increasingly desperate cries of the earth and its poor”.

The chief executives or chairs of BP, ExxonMobil, Shell, Total, ConocoPhilips, Chevron and several major investors including BlackRock and Hermes, responded by calling on governments to put in place carbon pricing to encourage low-carbon innovation, and called for greater financial transparency to aid investors.

However, they made no pledges to reduce their greenhouse gas emissions, and set no timetable for action.

In two statements, which came at the end of a two-day meeting in the Vatican that was addressed by the pope and led by senior Vatican churchmen, the signatories called for a “combination of policies and carbon pricing mechanisms … designed in a way that simultaneously delivers innovation and investment in low-carbon solutions while assisting those least able to pay”.

The oil companies’ pledges did not go far enough, said Mel Evans, climate campaigner for Greenpeace UK. “The oil majors knew all about the risk from climate change many years before most of us first heard about it. They knew where we were heading, they knew their products were the cause, and yet they kept it quiet and lobbied for business as usual,” said Evans. “And they’re still lobbying for business as usual. When it comes to saving the planet they will do what they are forced to do, and no more, which is why we’re having to block them from drilling new oil wells as we speak. Expecting leadership from them is a path to certain disaster.”

Emissions are rising at their fastest level in close to a decade, BP said this week, leaving an ever shorter period to prevent dangerous levels of global heating. Every year of high emissions takes the world closer to the brink, because it adds to the stock of carbon dioxide in the atmosphere, which can take a century to dissipate. Last month, the concentration of carbon dioxide in the atmosphere showed the second highest annual increase since continuous records began more than 60 years ago.

On Friday, BP served an injunction on the Greenpeace ship Arctic Sunrise to try to prevent it joining the activists occupying the oil company’s rig in Cromarty, Scotland. Greenpeace is trying to highlight the dangers of new oil drilling, which it says will gravely worsen the climate emergency.

In previous speeches, the pope has slammed “the continued search for new fossil fuel reserves” and said “fossil fuels should remain underground”.

Bob Dudley, chief executive of BP, said after the Vatican meeting: “The world needs to take urgent action to get us on a more sustainable path and it is critical that everyone plays their part – companies and investors, governments and individuals. This requires all of us to come together, build understanding and collaborate to find solutions. Constructive dialogues such as this meeting are essential in aligning key players on the steps needed to accelerate the energy transition while still enabling advances in human prosperity. I am grateful to his Holiness for continuing to support this critical engagement.”

BP’s chief economist warned this week that the world “should not rely on the generosity of the private sector” when it came to investing in key clean technologies such as carbon capture and storage, and called for the government to use taxpayers’ money to fund such initiatives instead.

BP’s profits doubled last year to a five-year high as its output of oil and gas soared.

Mark Campanale, founder and executive director of the Carbon Tracker, said: “We must forego business-as-usual protocols and short-term market-driven goals or face environmental and financial ruin of catastrophic proportions. Oil and gas companies have a crucial role to play in transitioning to a low-carbon economy but must today collectively take those hard decisions in the wake of determined investor and public pressure, and unambiguous scientific evidence.”

The IPCC warned last year that the world had about a decade to bring greenhouse gases under control, or face a probable rise in temperatures well beyond the 1.5C above pre-industrial levels they warned would bring devastating effects such as droughts, floods, heatwaves and damage to agriculture.