Pope Francis met teenage climate activist Greta Thunberg following his weekly audience at the Vatican Wednesday. The Swedish 16-year-old held a sign that read, "Join the Climate Strike" while waiting to meet the pope.

During the brief encounter, the pope encouraged Thunberg to continue her advocacy work. Thunberg has been organizing weekly climate change protests for months, gathering momentum around the world. Now, hundreds of thousands of students in more than 100 countries have taken part in school strikes to protest what they believe are their governments' failures to take strong enough action against global warming.

"Continue, continue," Francis told her, according to the Associated Press. "Go on, go ahead."

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"Thank you for standing up for the climate, for speaking the truth," Thunberg told Francis. "It means a lot."

Swedish teenage environmental activist Greta Thunberg holds up a sign as Pope Francis greets her at the end of his weekly general audience, in St. Peter's Square, at the Vatican. AP

Thunberg is in Italy to headline Rome's school strike Friday and address the Italian Senate. Pope Francis has called for action on global warming throughout his papacy, even writing an encyclical that urged people around the world to save the environment.

"Thank you so much for what you are doing," Thunberg's father, Svante Thunberg, told the pope. "It means everything. Everything."

Greta Thunberg told European Union leaders that they should "panic" about climate change during her address to the European Parliament in Strasbourg, France, Tuesday. "If the walls of our house truly came tumbling down, surely you would set your differences aside and start cooperating," she said. "Well, our house is falling apart, and we are rapidly running out of time. And yet, basically nothing is happening."

"You need to listen to us, we who cannot vote," she said, referring the upcoming European Parliament elections on May 23. "You need to vote for us, for your children and grandchildren," she said. "In this election, you vote for the future living conditions of humankind."

Thunberg was included on TIME's 2019 list of the world's 100 most influential people, which was unveiled Wednesday. "Fighting in her home country, Sweden, for a future free from pollution, environmental degradation and climate change, Greta is inspiring steadfast students and shaming apathetic adults," Parkland survivor and activist Emma González wrote for the magazine. "Climate change is our reality, and youth activists like Greta are doing everything within their power to work against it, and demand a change."