"Mitigating climate change and adapting to its effects are necessary to eradicate extreme poverty, reduce inequality and secure equitable, sustainable economic development," said Ban Ki Moon, U.N. secretary-general, in the keynote speech.

"This is an all-embracing moral imperative: to protect and care for both creation, our garden home, and the human person who dwells herein — and to take action to achieve this," said Cardinal Peter Turkson, who heads the Pontifical Council for Justice and Peace.

In September, the pope is scheduled to address Congress, as well as a United Nations summit meeting on sustainable development, where he is expected to reiterate his environmental message. The pope has said that climate change is “mostly” a result of human activity.

Pope Francis is not the first pope to address environmental issues, but his encyclical is expected to be the most comprehensive Vatican document so far on the links between sustainable development, concern for the poor and care of the planet.

View May 1, 2015 The Columbus Dispatch article
View April 30, 2015 Nature.com article
View April 29, 2015 USA Today article
View April 28, 2015 The New York Times article
View April 28, 2015 The Guardian article
View April 28, 2015 BBC News article