The world's three main Christian leaders issued an unprecedented joint appeal to members of their Churches to "listen to the cry of the earth" and back action to stem the effects of climate change.

In "A Joint Message for the Protection of Creation," Pope Francis, Archbishop of Canterbury Justin Welby and Orthodox Ecumenical Patriarch Bartholomew asked Christians to pray that world leaders at the United Nations Climate Change Conference (COP26) in Glasgow in November make courageous choices.

"We call on everyone, whatever their belief or world view, to endeavour to listen to the cry of the earth and of people who are poor, examining their behaviour and pledging meaningful sacrifices for the sake of the earth which God has given us," the message said.

Francis heads the 1.3 billion-member Roman Catholic Church, Bartholomew is the spiritual leader of the world's some 220 million Orthodox Christians and Welby is the senior bishop of the worldwide Anglican Communion, which has about 85 million members.

All three have been very active in environmental affairs and concur that climate change and global warming is at least partially caused by human activities such as the use of fossil fuels.

"We stand before a harsh justice: biodiversity loss, environmental degradation and climate change are the inevitable consequences of our actions, since we have greedily consumed more of the earth’s resources than the planet can endure," the message said.

It said recent extreme weather events, natural disasters, floods, fires, droughts and rising sea levels have shown that "climate change is not only a future challenge, but an immediate and urgent matter of survival."

Europe had its warmest summer on record this year, though only by a small margin over two previous highest temperatures for June-August, European Union scientists said earlier on Tuesday, and green groups have called for the COP26 conference to be postponed.

Typically delegates from more than 190 countries attend the annual talks, yet with many countries grappling with COVID-19 and poorer nations struggling to access vaccines, it should be delayed, the Climate Action Network (CAN) said.

Scotland's bishops have said Pope Francis, who underwent intestinal surgery in July, will take part in the Glasgow conference, health permitting.

A spokeswoman for Welby said he would attend. Bartholomew's office did not immediately respond to an email about his plans.

On Oct. 4, the Vatican will host a major gathering of world religious leaders and scientists to take a common stand to raise the stakes ahead of the Glasgow conference.

Called "Faith and Science: Towards COP26," is being organised by Britain and Italy. It will bring together some 40 leaders from the world's major religions and 10 scientists.

(Reporting by Philip Pullella; Editing by Raissa Kasolowsky)