LONDON — The parents of teenage climate activist Greta Thunberg made changes in their lives to “save” their daughter, not the world.

The teenager's father, Svante Thunberg, told the BBC on Monday that his 16-year-old daughter experienced depression for three or four years before going on school environment strikes.

He described how the young climate activist “fell ill” and stopped eating and talking to others.

To help her recover, he and his wife — Swedish opera singer Malena Ernman — made significant changes in their lives to become more environmentally friendly.

Svante Thunberg went vegan and Ernman stopped flying, which “changed her whole career,” he said.

“To be honest, she didn't do it save the climate. She did it to save her child because she saw how much it meant to her, and then, when she did that, she saw how much she grew from that, how much energy she got from it,” Thunberg said.

The father added that initially he did not support his daughter’s activism.

“We thought it was a bad idea, just the idea of your own daughter sort of putting herself at the very front line of such a huge question like climate change,” he said. “You wouldn't want that as a parent.”

His comments came during a special edition of the BBC Radio 4 Today program guest-edited by the young climate campaigner.

The BBC was heavily criticized for flying their presenter to Sweden to interview the teenager and her father, saying they “did not have time for other means of transport.”

The program also included interviews with outgoing Bank of England chief Mark Carney, who said the financial sector is responding too slowly to the climate crisis, and environment filmmaker David Attenborough.