A tech company executive and nature photographer friend who lives in Stockholm, Sweden tells me Greta Thunberg, the teenage climate activist who took the world by storm a year ago, is a casual neighbor of his. He sees her constantly as he make his frequent rounds around Stockholm's parliament district. Thunberg, now 17, is "old hat" — his words — for anyone who's lived in Sweden for any length of time and is even passingly familiar with the daily news reports of the growing climate crisis.

So he was more than a little startled when, just over a year ago, Thunberg became a global sensation, arguably Sweden's most widely recognized cultural export since ABBA. To my friend, she was — and remains — the slightly peculiar neighborhood kid who, when she isn't protesting climate change outside Sweden's parliament buildings, can be seen playing with her dogs Roxy and Moses in the local park.

It's that gentle, exquisitely personal side of a 17-year-old still learning to navigate her way through an uncertain future that jumps out over and over again in I Am Greta, the evocative, surprisingly moving feature-length documentary that makes its streaming debut Friday on Hulu.

I Am Greta, directed with a refreshing low-key sensitivity by the young, relatively unknown activist filmmaker Nathan Grossman, a fellow Swede who earned the confidence of Thunberg's father Svante, made its film festival debut at the Venice Film Festival this past September. That's Venice, Italy, not Venice Beach, Calif. Thunberg is a global phenomenon, and so is this film. In just the few short weeks it has been playing on the festival circuit across Europe and North America, I Am Greta has taken on a life of its own. (Hulu is the film's primary financial backer, which is why the streaming service has exclusive rights to its TV debut Friday.)

Anyone expecting an angry screed, or even a David Attenborough-style clarion call to preserve what's left of the world's remaining wild spaces, is bound to be disappointed. This is a personal profile of a shy, Asperger's-afflicted teenager trying to make sense of her place in the world, and there are moments when it is absolutely exquisite.

Grossman became part of the family, faithfully recording the then-16-year-old's everyday routine over the course of an entire year, and was one of the few people to accompany her, camera in tow, on her trans-Atlantic sail by solar- and wind-powered racing yacht from the UK to the United Nations climate conferences in New York City. It's those moments of privacy on the open sea, surrounded by wind and towering waves, that provide some of the film's most intimate, stirring profoundly moving moments as — free from the constantly prying eyes of the outside world — she becomes positively radiant. The sea does that to a person. One of the knocks on Thunberg is that she so rarely smiles, and yet there are moments in I Am Greta when she does exactly that, in sudden moments that happen when they're least expected.

There's a lot to unpack in I Am Greta, from the family videos of a young child seemingly happy and deceptively at peace with herself, to the shy, troubled, reclusive tweener she would become — racked by depression, silent and moody and refusing to eat — through her years of emotional struggle — she candidly admits her autism, and in fact uses it to press her cause — to reluctant climate crusader traveling the world stage and meeting dignitaries from Pope Francis and UN Secretary-General António Guterres to celebrity climate activists Arnold Schwarzenegger and Leo DiCaprio.

Grossman has crafted an exquisitely personal, artistic statement with his film. There's none of the bullying voiceover or loud, tacky ersatz music that marks most TV profiles. The voice is singularly her own. And at little under two hours, there's enough here to almost — almost — get to know the complex, often inscrutable person she is.

For a teenager, or just about anyone for that matter, she is singularly unimpressed by celebrity. A less star-struck teenager you could not find, which is possibly one of the things her older detractors — including the soon-to-be ex-President of the United States — find unsettling about her.

Thunberg told journalists and film reviewers in Venice, shortly after seeing the finished film for the first time, that it was the first time she had seen herself reflected on screen as she really is, "and not the person the media frames me to be, (this) angry, naive child who sits in the United Nations General Assembly screaming at world leaders. Because that's not the person I am."

I Am Greta, she added, "definitely makes me seem like a more shy, nerdy person, which is the person that I am."

Those reviewers who've dislike I Am Greta – on both sides of the climate argument – frame their arguments in political terms, which is a mistake. This is not a political film. It's a profile of a real person, who doesn't always say what people want to hear or even what they need to hear.  I Am Greta has been dismissed as "advertorially polite," and "slickly inessential" (Financial Times) and "a polished documentary that doesn't quite offer the full picture" (The Irish News), but those reviews miss the point.

Thunberg is complex and given to playing to people's perception of her, and it's that diffidence — a teenager's querulous view of the world — that Grossman captures perfectly. She is full of surprises, with a skewed yet strangely all-seeing view of the world and a tart, occasionally cutting sense of humor — just ask the soon-to-be-retired US Commander-in-Chief.

I Am Greta is "a very surreal movie," Thunberg says in her voiceover, "because the plot would be so unlikely."

There are moments of real power here, especially when the camera eavesdrops without prying on private conversations between a teenage girl battling depression and her dad who is privately fretful for her future.

Don't worry, he tells her as they leave a conference center in Poland, early in her climate campaign, "No one will know who you are."

"That's nice," she replies, with disarming honesty.

I Am Greta keeps coming back to the sea. There are news photos of her, taken by Grossman and her dad Svante, where she beams radiantly off the racing yacht's deck into a bright sun and her smile is blinding, and then there's the harrowing moment in the film where she's huddled down in the yacht's cabin, terrified, as a black wall of water towers over the boat in a driving wind, and she plaintively admits, while recording a message to her opera singer mom, back in Sweden: "I don't want to have to do all this. It's too much for me. I know that this is important and what's at stake. But it's such a lot of responsibility."

I Am Greta is by turns heartfelt and gut-wrenching, poignant and yet terrifying. It's not the film you might expect, but then neither is Greta Thunberg. Love it or hate it, and there are those on both sides of the argument, it is absolutely worth watching.