The former Archbishop of Canterbury, Baron Williams of Oystermouth, was among religious leaders from around the world who took part in a climate repentance ceremony on Sunday.
The multi-faith ceremony saw faith leaders seek forgiveness for climate sins, and call for humility and action from world leaders as they seek to address climate change during Cop27.
The latest UN climate change conference of world leaders started last week in Sharm El Sheikh, Egypt, and runs until 18 November.
Climate finance and compensation, pledges to curb greenhouse gases, and water scarcity are some of the topics on the agenda of the talks.
The climate repentance ceremony brought together leaders from Egypt, the US, Israel, India, Spain and the UK.
They took part in a penitential march up Parliament Hill in London, carrying scrolls with 'Ten Principles for Climate Repentance'.
This was followed by a two-hour ceremony at the New North London Synagogue.
Leaders came from the Christian, Jewish, Muslim, Buddhist, Sikh and Hindu traditions.
"Humans have caused untold harm to our precious planet," said Baron Williams.
"Climate repentance means all of us holding up our hands to climate sins, something that is all too often missing from these conversations.
"Only when we deeply acknowledge the past and the present, can we make the courageous changes necessary for a future of climate justice.
"The Ten Principles set out the path for that future."
Patriarch Bartholomew, who is known as 'the Green Patriarch' for his climate activism, said, "The abuse of nature and the exploitation of its resources are a sin against God the Creator and the gift of creation."