Many of the world’s leading oil producers announced their support for carbon pricing schemes following an impassioned plea by Pope Francis for a “radical energy transition” during a climate summit at the Vatican on Friday, according to the Associated Press.

The pope used the occasion to urge world leaders to stop wasting time in the fight against climate change, framing it in terms of social justice.  

“We must take action accordingly, in order to avoid perpetrating a brutal act of injustice towards the poor and future generations,” he told those gathered.

“It is the poor who suffer the worst impacts of the climate crisis,” he added.

The religious leader said that carbon pricing is an instrumental tool for accelerating the shift toward renewable energy, adding that it’s “essential if humanity is to use the resources of creation wisely.”

Various oil executives agreed.

“Reliable and economically meaningful carbon pricing regimes, whether based on tax, trading mechanisms or other market-based measures, should be set by governments at a level that incentivizes business practices,” said the CEOs of ExxonMobil, BP, Royal Dutch Shell, Total, Chevron, and Eni in a joint statement at the end of the summit.

Carbon pricing schemes have long been seen as a “business-friendly” approach to reducing carbon emissions. Currently, more than 40 countries and 20 cities have some sort of carbon pricing arrangement on the books, and countries like China are expected to enact similar rules in the near future.

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There are two main forms of carbon pricing. The most straightforward involves taxing companies whose carbon emissions exceed a limit set by the government. The second form, known as cap-and-trade, creates a market for carbon credits. Companies whose emissions exceed the limit set by the government can buy carbon credits from companies with low emissions levels.

Carbon pricing has had mixed results around the world. A carbon tax enacted in the United Kingdom in 2013 helped to drive down the use of coal, and Canada’s carbon tax is a core part of the commitments it made under the Paris climate agreement, according to the New York Times.  Other countries have faced pushback and protests after enacting carbon taxes because of how it can lead to cost-of-living increases, and have struggled to set a tax rate that actually drives down emissions.

Either way, carbon pricing is more effective than not doing anything, and can be part of a broader plan to reduce emissions.

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Countries around the world are running out of time to reduce their emissions. The Paris climate agreement aims to keep global temperatures rising more than 2 degrees celsius above pre-industrial levels. In order to achieve that goal, global emissions essentially have to reach zero by 2030.

Currently, countries aren’t on track to eliminate emissions until well beyond 2050, which could lead to catastrophic climate change.

In fact, far from declining, emissions have been rising in the past few years.  

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Pope Francis has long advocated for fighting climate change, and often leads by example. For instance, he’s directed the Catholic Church to divest from fossil fuels.

While the odds are daunting, Pope Francis said that climate change can be mitigated if corporate and political leaders step up.

“There is still hope and there remains time to avoid the worst impacts of climate change,” he said. “Provided there is prompt and resolute action.”