VATICAN CITY — With a poet's lyricism, a former chemist's precision and a pontiff's moral thunder, Pope Francis recast humanity's relationship with nature in stark ethical terms, hoping to spur a warming, filthy world to clean up its act "before it's too late." 
In issuing "Laudato Si," his much-anticipated encyclical on climate change, the pope on Thursday took an extraordinary approach to an environmental issue often framed in the dry language of science. Francis' teaching document is a melodic yet radical indictment, depicting a materialistic and wasteful society that is hurting the planet and its poorest people. 
 Pope Francis Urges Greater Care For Environment 0:50
He challenges the world to stop pollution, to recycle and carpool and to do without air conditioning — and makes it a moral imperative. 
"The exploitation of the planet has already exceeded acceptable limits and we still have not solved the problem of poverty," he writes. 
The pope's "marching orders for advocacy," as the head of the U.S. Conference of Catholic Bishops calls it, comes as the world nears make-or-break time for international climate change negotiations that start late this year in Paris. 
Francis said he hoped his paper would lead both ordinary people in their daily lives and decision-makers at the Paris U.N. climate meetings to a wholesale change of mind and heart, urging all to listen to "both the cry of the Earth and the cry of the poor." 
U.N. Secretary-General Ban Ki-moon, who has made the issue of climate change his top priority since taking the reins of the world body eight and a half years ago, thanked the pope "for taking such a strong stand on the need for urgent global action." 

Invocation to climate talks 

In some ways, the pope's encyclical and its prayers serve as an invocation to the climate talks. 
"As we prepare for global climate negotiations in Paris this December, it is my hope that all world leaders — and all God's children — will reflect on Pope Francis's call to come together to care for our common home," President Barack Obama said in a statement Thursday afternoon. 
Scientific data released on Thursday backed up Francis' concerns. The U.S. National Oceanic and Atmospheric Administration provided figures showing that last month was the hottest May around the globe in 136 years of global records. NOAA calculated that the first five months of 2015 made up by far the hottest year on record, with very real effects. For example, 2,200 people have died in India's heat wave.