BBC screenshot by Leslie Katz/CNET

It's been quite a year for young climate change activist Greta Thunberg, who's capping off an eventful 2019 with major props from David Attenborough.

On a BBC radio program Monday, the famed British broadcaster and naturalist told the teen she'd "aroused the world" to climate change. He also said she'd "achieved things that many of us who have been working on it for 20-odd years have failed to achieve. I'm very grateful to you. We all are."

Thunberg, in turn, expressed admiration for Attenborough, saying his nature documentaries had inspired her interest in the environment. The pair met for the first time for Monday's Today program, which Thunberg guest-edited. Their face-to-face chat happened via Skype, as they wanted to avoid the carbon impact of flying, and swapped opinions about the climate -- and activism.

"We don't want to spend our time marching through the streets, but we have to," Attenborough told the Swedish 16-year-old, "and you've shown very great bravery in doing that." This year, Attenborough narrated Our Planet, an eight-part documentary series for Netflix that explores the impact of climate change.

The pigtailed Thunberg has drawn worldwide attention since she first sat outside the Swedish parliament in August 2018, protest sign in hand, demanding that world leaders act on climate change.

Earlier this month, Time named Thunberg its Person of the Year, the youngest recipient ever bestowed the title. The publication described her as the "most compelling voice on the most important issue facing the planet."

In March, Thunberg was nominated for a Nobel Peace Prize. She's getting a Hulu documentary set to premiere next year. She's even getting her own mural in San Francisco.

But not all the attention has been laudatory. As part of the same BBC radio program, Greta's father Svante Thunberg said that while his daughter has been happier since becoming an activist, he worries about the hateful comments she received.

She's talked about being criticized on social media for her looks, clothing and behavior, among other things.

Her dad did say she deals with the criticism "incredibly well."