According to Breitbart:
The Pontifical Academy of Sciences has invited California governor Jerry Brown to deliver a keynote address in their upcoming meeting on climate change to be held in the Vatican.
The Nov. 2-4 Vatican workshop titled “Health of People, Health of Planet and our Responsibility: Climate Change, Air Pollution and Health” will attempt to link up the health risks posed by air pollution with anthropogenic climate change driven by carbon emissions.
This is not the first time the Vatican has offered a platform to the contentious California governor from which to proclaim his views on global warming.