Senior public relations counselors can't be as dismissive of the pope's message, which goes to the very purpose of a corporation.
If one believes that a corporation's only purpose is to create wealth (value) for its shareowners, then its environmental impact is simply an "externality" that need only be addressed to the extent required by law and regulation. And it's perfectly free to do anything legal to shape those laws and regulations to its advantage.
If on the other hand one believes a corporation's purpose is to create wealth (value) for everyone who contributes to its success and bears the cost of its failures, those "externalities" have moral significance. Corporations need first to ask themselves what they can do to minimize the environmental impact of their operations. And then they need to ask what they can do within their areas of competence to deal with the broader impacts on their stakeholders.
Public relations counselors should recognize that a significant portion of the public are embracing the pope's message. That's not a call for more green-washing. But for a thoughtful discussion of the underlying question: what is the purpose of the corporation?
Adam Smith, the guy who essentially invented capitalism, was first a moral philosopher. He wouldn't have been so quick to suggest the pope should stick to his rosary. In fact, he would have seen the pope's encyclical as the continuation of a discussion Smith himself started.