Pope Francis’ top aide on climate change urged businesses on Wednesday not to let the pursuit of profit get in the way of protecting the planet.

The remarks came as the Vatican is due to release a papal encyclical, or formal letter, on the issue.

Cardinal Peter Turkson, who helped draft the encyclical, said the paper would be presented in the second half of June, two months before the pope is due to address the U.S. Congress and a United Nations meeting on sustainable development.

“Our lives must become more sustainable,” Turkson told a conference on economic growth and sustainability organized by the Vatican and the Netherlands. “This is not just about business and profits.”

Turkson said business had a responsibility to produce “goods that are good and services that truly serve… and provide a benefit for others and not just for themselves.”

He cited the United States, where now “there are more jobs in solar energy than in the coal sector.”

Pope Francis has said he believes man is primarily responsible for climate change. Though previous pontiffs have addressed environmental issues, the encyclical is expected to be the most thorough papal teaching yet on links between economic development, poverty reduction and environmental protection.

The pope hopes the encyclical will influence world leaders to enact sweeping climate change policies at a summit in December.

The Vatican’s recent warnings against climate change have been criticized by some who say the pontiff risks confusing people by making it seem that climate change is part of Catholic faith. They say the pontiff should not wade into highly-politicized scientific debates.

Turkson defended the pope’s activity. He said the point was not politics, which was a reality of every day life. “The issue is how much people are aware of scientific data that the climate is changing.”