Two generations, one prophetic call for climate justice

At 82-years-old, with a wreath of white hair and an often-delighted smile, Francis sees action on climate change as a way to protect vulnerable people, an essential part of his Christian vocation. At 16-years-old, with her hair in a braid, Greta sees action on climate change as a fight that is essential to her future, a fight for her very survival.

Francis recognizes that older generations have a responsibility to solve the challenges they've created. Greta recognizes that younger generations have an opportunity to solve the challenges they've inherited.

Catholic and secular, old and young, male and female — and yet. These two leaders are united in their unwavering commitment to action. As the United Nations climate body debates the placement of parentheses, true leadership like theirs is desperately needed.

The world is hungry for courage and commitment. Everywhere Greta walked, ordinary people took pictures by the hundreds. In the Vatican, guards asked for selfies with Greta. Nuns asked for selfies with Greta.

Everyday people are drawn to Greta because she fulfills a need that grows sharper with every passing day: our need for honesty.

Greta recently told the European Parliament that "the house is on fire." Francis has written that "the earth, our home, is beginning to look more and more like an immense pile of filth."

These leaders respect us enough to admit that climate change is real. They know that storms are becoming stronger, that mosquito-borne disease is spreading, that deserts are growing. They know that these changes mean more sickness, more hunger, more conflict.

But they also know that we have the capacity for change. They know that in the past, we have banded together to achieve something greater than ourselves. They look at our incredible advances in medicine, at the increase in literacy, at the best of what humanity has to offer. They know we can solve this.

Christians are, by definition, people of hope. As Francis has written, "human beings, while capable of the worst, are also capable of rising above themselves, choosing again what is good and making a new start."

On May 24, we will have another chance to choose what is good. May 24 is the date of the next in the global climate strikes that were started by Greta. It also happens to be the anniversary of "Laudato Si', On Care for Our Common Home," Francis' encyclical on climate change. All people — and especially all Catholics — should seize this opportunity to stand up for the greater good.

The massive strikes have shown the power of unity in hope. In March, 1.4 million people participated in over 2,000 cities. Young Catholics were part of the mobilization, taking part under the banner of the Laudato Si' Generation.

This is only the beginning. Strength is gathering in all corners of the world, and we stand poised to truly protect this Earth, our common home, which belongs to us all. Business as usual is over. We have 12 years to bend the arc of emissions downward. Imagine the age you will be in 12 years, the age your children will be. This is how much time we have left.

Witnessing the meeting of these two prophetic leaders was a blessing. It reminds us that in the face of humanity's greatest crisis, a bold commitment to the greater good unites us. Across generations and cultures, true leadership is plain to see.

[Tomás Insua is executive director of the Global Catholic Climate Movement.]