Pope Francis and the spiritual leader of the world's Orthodox Christians have issued a joint appeal for political leaders to "support the consensus of the world" that climate change and other environmental ills have created an ecological crisis that is harming the world's poorest the most.
Francis and Patriarch Bartholomew I called for urgent action to "heal our wounded creation", warning that generations to come will suffer unless concrete and collective action is taken.
They blamed the current state of degradation on "moral decay" and "our insatiable desire to manipulate and control the planet's limited resources, and our greed for limitless profit in markets".
Christianity's top spiritual leaders issued the appeal on Friday, which both Catholic and Orthodox churches mark as a day of prayer for God's creation.
Their message did not single out individual countries, but the administration of President Donald Trump has announced it is withdrawing the United States from the Paris climate accord, which seeks to curb emissions of heat-trapping gasses in the atmosphere.
Mr Trump has described man-made global warming as a hoax and he has moved to delay or roll back federal regulations limiting greenhouse gas emissions, arguing they made American industries uncompetitive.
Russia, the world's biggest crude oil producer and its fifth-largest emitter of greenhouse gases, signed the Paris agreement but has delayed formally ratifying it.
Its voluntary goals are among the weakest submitted by any country, allowing the overwhelmingly Orthodox nation to spew more planet-warming emissions in future years, not less.
In their message, Francis and the Orthodox leader blasted the "alternative world view" that considers nature as a private possession to be exploited, regardless of the cost.
"We urgently appeal to those in positions of social and economic, as well as political and cultural, responsibility to hear the cry of the Earth and to attend to the needs of the marginalised, but above all to respond to the plea of millions and support the consensus of the world for the healing of our wounded creation," they wrote.
"We are convinced that there can be no sincere and enduring resolution to the challenge of the ecological crisis and climate change unless the response is concerted and collective, unless the responsibility is shared and accountable, unless we give priority to solidarity and service."
The message echoed that of Francis's landmark 2015 encyclical Laudato Sii (Praise Be), where Latin America's first pope called for a cultural revolution to correct a "structurally perverse" economic system in which the rich exploit the poor, turning Earth into an "immense pile of filth".
In that document, Francis cited writings by Bartholomew, who championed the environmental cause long before Francis became pope.
Both leaders frame climate change as an urgent moral issue to address, saying humans have a moral obligation to protect God's creation.
Francis gave a copy of the encyclical to Mr Trump when they met earlier this year.