Humans are causing climate change, and there will be “grave consequences” if we don’t act fast – that’s the main message from Pope Francis’ long-awaiting encyclical on climate change and the environment.  A copy leaked out days before the official roll out on Thursday.

“Humanity is called to take note of the need for changes in lifestyle and changes in methods of production and consumption to combat this warming, or at least the human causes that produce and accentuate it,” Pope Francis writes, using definitive language that will irk some conservatives.  “Plenty of scientific studies point out that the last decades of global warming have been mostly caused by the great concentration of greenhouse gases (carbon dioxide, methane, nitrogen oxide and others) especially generated by human action.”

The draft, obtained by Italy’s L’Espresso Magazine, puts the Pope in alignment with the environmental movement.  He chastises those global warming deniers who are acting as roadblocks to solutions.  “The attitudes that stand in the way of a solution, even among believers, range from negation of the problem, to indifference, to convenient resignation or blind faith in technical solutions,” says Francis.

Pope Francis declares that access to clean drinking water is “an essential human right, fundamental and universal”.  He says climate change disproportionately harms the world’s poor populations, whose “livelihoods depend heavily on nature reserves”.  And he accuses the wealthy and powerful of “making the problems or hiding the symptoms” of climate change.

The pontiff is calling for the creation of an international body to oversee the transition from polluting to clean technologies, and to help developing nations along.