Swedish teenage environmental activist Greta Thunberg has brought her climate change campaign to the Vatican, where she met with Pope Francis and carried a sign saying "Join the climate strike."

Thunberg arrived late for Francis' general audience on Wednesday and took her seat in the VIP section in St. Peter's Square. Francis went up to her at the end of the audience, where Thunberg showed off her sign.

She is in Rome to headline Friday's "school strike," the growing worldwide youth movement she spearheaded demanding faster action against climate change. Thunberg will also address the Italian parliament.

In Francis, Thunberg has found a kindered spirit. The Jesuit pope has made fighting climate change and caring for God's creation a pillar of his papacy.