WASHINGTON —Piers Sellers, a climate scientist and former astronaut who gained fame late in life for his eloquent commentary about the earth’s fragility and his own cancer diagnosis, has died. He was 61.

Sellers died Friday morning in Houston of pancreatic cancer, NASA said in a statement.

Sellers shared his astronaut’s perspective on climate change in Leonardo DiCaprio’s documentary, “Before the Flood,” released this fall. He told DiCaprio that seeing the earth’s atmosphere as a “tiny little onion skin” from space helped him gain a fuller understanding of the planet’s delicacy.

He wrote a New York Times op-ed about grappling with the meaning of his life’s work after learning he had terminal cancer. In both the film and the op-ed, he was optimistic, saying he expected human ingenuity to rescue the planet from a dire future of runaway global warming.

“Piers devoted his life to saving the planet,” NASA Administrator Charles Bolden said in a statement. “His legacy will be one not only of urgency that the climate is warming but also of hope that we can yet improve humanity’s stewardship of this planet.”