Pope Francis is hosting a gathering next week at the Vatican with executives of major oil producers and investment firms to talk about how the companies can address climate change, according to several people familiar with the event.

Why it matters: It’s one of the most significant developments showing how corporations are working with other world leaders on climate change amid President Trump’s whole-scale retreat on the issue.

Situational awareness: One year ago today, Trump announced his intention to withdraw America from the Paris climate deal, which now has support from every country except the United States. Three years ago, Pope Francis wrote his encyclical — a papal letter sent to all bishops of the Roman Catholic Church — on the importance of addressing climate change, a first in the church’s history.

Here’s a list of some of the participants in the private conference, with more expected: