Amazon founder Jeff Bezos is promising for the first time to give away most of his wealth within his lifetime.

Bezos is currently the fourth richest person in the world, with an estimated net worth of $124.1 billion.

In an interview with CNN’s Chloe Melas that aired on Monday, Bezos confirmed that he intends to donate the majority of his wealth to charitable causes. He says most of it will go toward fighting climate change, and to people who can unify humanity in the face of deep social and political divisions.

As for when? Philanthropy “is really hard,” Bezos said in the interview. “We’re building the capacity to be able to give away this money.”

On Saturday, Bezos announced Dolly Parton as the $100 million grant recipient of the Bezos Courage and Civility Award.

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