Pope Francis revealed Wednesday he will publish an update to his seminal 2015 thesis on the environment in October, just weeks before the next round of UN climate talks.

The 86-year-old pontiff earlier this month mentioned plans to write a second part of "Laudato Si" but gave no details beyond saying it would address "current issues".

His so-called encyclical in 2015 laid the blame for global warming squarely on humanity's shoulders, and was seen as influential in United Nations climate talks in Paris later that year that led to landmark commitments. 

At his weekly audience at the Vatican on Wednesday, Pope Francis set the date for his new version as October 4 - just weeks before the next round of UN talks, at COP28 in the United Arab Emirates in November and December. 

"On that date I intend to publish an exhortation, a second Laudato si," he said.

"Let us join our Christian brothers and sisters in the commitment to safeguard Creation as a gift of the Creator. 

"It is necessary to stand with the victims of environmental and climate injustice, striving to bring an end to the senseless war on our common home, which is a terrible world war." 

Earlier this month, Vatican spokesman Matteo Bruni said the updated document would focus in particular on recent extreme weather events and catastrophes across the world. 

In his 2015 thesis "on care for our common home", the Argentine pope urged the world to act quickly to prevent climate change from destroying the planet.

He bemoaned the weakness of political responses and argued rich countries must bear responsibility for creating the problem, and finance a solution.

The document was hailed by climate activists and politicians including then US president Barack Obama.

The date of October 4 marks the end of the Christian Season of Creation, which begins with the World Day of Prayer for Creation on September 1.