“The Earth, our home, is beginning to look more and more like an immense pile of filth.” These aren’t the words of a radical sociologist or rogue climate scientist. They aren’t the words of a Conversation editor either. Nor are these:

“A selfish and boundless thirst for power and material prosperity leads both to the misuse of available natural resources and to the exclusion of the weak and disadvantaged.”

These are in fact quotes from Pope Francis, who died last weekend.

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I never thought this job would have me writing newsletters in praise of a papal climate influencer, but here we are. You can read various obits and interesting takes on Pope Francis and what’s next for the Catholic church elsewhere on The Conversation. But here I want to focus on his thoughts on climate change and the impact he had.

Our common home

In 2015, two years after becoming pope, Francis published Laudato Si (Praise Be to You), a 183-page papal letter sent to all Catholic bishops on “care for our common home”. It was a significant intervention made just a few months before the climate summit that led to the Paris agreement.

Writing at the time, sustainability professor Steffen Böhm said that what made it so radical “isn’t just [Pope Francis’s] call to urgently tackle climate change. It’s the fact he openly and unashamedly goes against the grain of dominant social, economic and environment policies.”

For Böhm, who was then at the University of Essex but now works at Exeter, this radical message “puts him on a confrontation course with global powerbrokers and leaders of national governments, international institutions and multinational corporations”.

He quotes a section where the Pope says “those who possess more resources [and] power seem seem mostly to be concerned with masking the problems or concealing their symptoms, simply making efforts to reduce some of the negative impacts of climate change”. The Pope warns that “such effects will continue to worsen if we continue with current models of production and consumption”.

Böhm points out the Pope “might be the only person with both the clout and the desire to meaningfully deliver a message like this”.

Read more: Pope’s climate letter is a radical attack on the logic of the market

Bernard Laurent of EM Business School in Lyon, says that in France the Pope’s message “managed to bring together both conservative currents – such as the Courant pour une Écologie Humaine (Movement for a Human Ecology), created in 2013 – and more open-minded Catholic intellectuals such as Gaël Giraud, a Jesuit and author of Produire Plus, Polluer Moins : l’Impossible Découplage? (Produce more, Pollute Less: the Impossible Decoupling?)”

Read more: Pope Francis and Laudato Si’: an ecological turning point for the Catholic Church

Clearly, this was a unique figure able to reach people who might not listen to a Greta Thunberg or an Al Gore.

But, while it’s great the Paris agreement was signed, it was still filled with the exact sort of market logic and buck-passing – carbon credits, “emit now, clean up later”, and so on – the Pope had criticised a few months previously. And climate change itself only got worse. In the years following, Pope Francis spoke at the UN and published a series of other “exhortations” related to climate change.

Did any of this make any difference?

Celia Deane-Drummond is a theology professor at the University of Oxford and director of a research institute named after the 2015 papal letter. In a piece published the same day Pope Francis’s death was announced, she looked at his influence on the global climate movement.

Deane-Drummond notes Pope Francis’s emphasis on listening to Indigenous people for instance in his lesser-known exhortation Querida Amazonia, which means “beloved Amazonia”, from February 2020.

“This exhortation resulted from his conversations with Amazonian communities and helped put Indigenous perspectives on the map. Those perspectives helped shape Catholic social teaching in the [papal letter] Fratelli Tutti, which means ‘all brothers and sisters’, published on October 3 2020.”

A key influencer

Perhaps the Pope’s biggest influence was on activists rather than policymakers. Deane-Drummond says he was often mentioned by participants in a research project on religion, theology and climate change she was part of.

“When we asked more than 300 [religious] activists representing six different activist groups who most influenced them to get involved in climate action, 61% named Pope Francis as a key influencer.”

The 2015 papal letter also gave rise to the Laudato Si movement which Deane-Drummond points out “coordinates climate activism across the globe. It has 900 Catholic organisations as well as 10,000 of what are known as Laudato Si ‘animators’, who are all ambassadors and leaders in their respective communities.”

Read more: Three ways Pope Francis influenced the global climate movement

There are specific religious arguments he was able to make to appeal to these groups, note Joel Hodge and Antonia Pizzy of Australian Catholic University.

They write that: “Francis argued combating climate change relied on the ‘ecological conversion’ of the human heart, so that people may recognise the God-given nature of our planet and the fundamental call to care for it. Without this conversion, pragmatic and political measures wouldn’t be able to counter the forces of consumerism, exploitation and selfishness.”

Read more: Pope Francis has died, aged 88. These were his greatest reforms – and controversies

It’s not an argument that will particularly work on me. But then addressing the climate crisis will require all sorts of people to be persuaded of the need for serious action, including policy wonks, tech bros, radical activists, worried parents and, yes, people motivated by their religion.

The last pope didn’t have to say anything about the climate crisis. It’s not necessarily in the job description. But it’s a good thing that Pope Francis did speak about it and, as Deane-Drummond says: “We can only hope [the next pope] will build on his legacy and influence political change for the good, from the grassroots frontline right up to the highest global ambitions.”