How does it feel to be Greta right now? The teen has inspired a global movement - and death threats. Eleanor Steafel, in Stockholm, talks to those who know her best.

It has been a watershed week in the spotlight for Greta Thunberg, the 16-year-old general of a worldwide teen army, who crossed the Atlantic on an eco yacht. It began with a speech to hundreds of thousands of school strikers in New York last Friday, on a day of global action inspired by the solo protest she began outside the Swedish parliament last year.

Then came Monday's fiery address to the UN's Climate Action Summit, watched by millions around the world and followed by an obligatory Twitter stand-off with President Trump (which, most agree, Thunberg won).

Meanwhile, the backlash has been mounting. Thunberg's passion is undeniable, but for some, she represents everything they find distasteful about preaching activists - "the pigtailed prophet of planetary paranoia", as one commentator put it. Others have openly expressed concern about her emotional state and mental health.

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Yet more have flocked to support her, urging denigrators not to "confuse passion for hysteria" and holding "Greta the Great" up as a beacon of hope.

Whatever your take, it is a lot for young shoulders to bear; and easy to forget that until this time last year, they belonged to an anonymous Swedish teenager with Asperger's syndrome.

Her friends and comrades, 4,000 miles away back in Stockholm, watched her UN speech live in the early hours and wept. "I think we all cried," says Isabelle Axelsson, a co-founder of the school strike movement that Thunberg pioneered. "We weren't expecting it to be so emotional."

I meet Isabelle and her twin sister Sophia in the small sunlit square in front of the Riksdag, the imposing Swedish government building where they have sat each morning since their friend set sail, last month.

The 18-year-olds, like many other Swedish teens, were inspired to join the Friday school strike Thunberg began last August, as a lonely figure with a hand-painted sign reading "Skolstrejk för klimatet" (school strike for climate).

The twins' teachers and parents were broadly supportive, and both found their grades improved despite missing school once a week. "I studied a lot during the weekends, I was less sick, less depressed at home, I had more energy," Isabelle tells me, as confidently and eloquently as Thunberg.

It has been hard, though, to watch her friend in the line of fire this week. "Greta doesn't want to have all the focus on her, but she has realised that this is how we can break through, this is how we can make a difference. It's a lot of pressure. Both because we need to succeed [...] and then also because people are watching us. I think there's some form of worry from many people about how she's doing and the pressure, because it's not only trolling and hate for her, she gets literal death threats."

The general consensus among climate commentators is that Thunberg is actually "strikingly non-radical", yet some adults clearly find her unnerving.

"This child - and she is a child - has been scared and her parents are letting her be controlled by that fear," said Erick Erickson, the American Right-wing commentator, in a post about "the Left's abusive use of Greta", in which he blamed her parents for "depriving her of a sound education so she can lecture grown-ups.

Her friends and fellow strikers tell me this couldn't be further from the truth.

Thunberg's revolution started at home, but when she first approached her parents with the idea of striking, they were unconvinced.

"They did not support the idea of school striking, and they said that if I were to do this, I would have to do it completely by myself and with no support from them," Thunberg has said previously.

She eventually convinced her family to start lowering their carbon footprint by adopting a vegan diet and giving up air travel, which also meant her mother, Malena Ernman, a famous opera singer in Sweden, had to give up performing internationally.

Her father Svante, a former actor, now follows his eldest daughter around the world, while his wife and their other daughter, Beata (a budding singer like her mother), stay in the family home - a modest apartment block in a leafy, middle-class area of Stockholm, which feels a world away from the UN stage in Manhattan.

"Greta and her dad are a great team," says Torunn Hansen-Tangen, a mother of three who stands alongside Thunberg at the Stockholm strike every Friday. "As a mum, I worry about putting someone in the spotlight so young. She has the world on her shoulders now. But she seems to have amazing parents. As I understand it, she's pretty unstoppable. It's pretty hard to tell her what to do."

In Sweden, she is roundly adored by media and politicians alike. "Her passion, it isn't too much for us here," one leading Swedish journalist tells me. "She is from a normal and very nice family. She is well loved and taken seriously here on both sides of the political landscape."

Outside Sweden, however, vitriol has been steadily rising.

Arron Banks, the Leave.EU donor hinted that he'd like her to become the victim of a "freak yachting accident" as her voyage began, and suggestions have been made that there is a team of puppeteers behind her stratospheric rise.

Freak yachting accidents do happen in August ... https://t.co/6CPePHYLtu

— Arron Banks (@Arron_banks) August 14, 2019

At first, she was affiliated with We Don't Have Time, a non-profit foundation set up by Swedish climate entrepreneur Ingmar Rentzhog, after he met her outside the Riksdag in the early days of her protest and signed her up to be a youth adviser.

They parted ways last year, after the company used her name without her permission to promote the start-up arm of their business.

These days, Thunberg receives input for her speeches from scientists, but insists there is no team of PR experts or money men behind her, pulling the strings. "People love to spread rumours saying that I have people 'behind me' or that I'm being 'paid' or 'used' to do what I'm doing," she wrote on Facebook. "There is no one 'behind me' except myself."

Ebba Gärdekrans, 19, has known Thunberg since they were children at the same school for additional needs, and she has watched her friend come out of her shell as her profile has grown. "I knew her before she was outspoken," she tells me, amid the hubbub of the 30,000-strong march that moved through the streets of Stockholm yesterday.

"When I saw her speech this week, I was just in shock. It made me cry. We all have a lot of pressure but I can't imagine being the focus of the whole movement."

Previously, when Thunberg's army of school strikers took to the streets, the only adults among them have been parents keeping a watchful eye as their children shout: "You will die of old age - I will die of climate change!"

Today, on a beautiful autumnal morning in Stockholm, thousands more older people have joined them on the streets in peaceful protest, holding pictures of Thunberg, or playing videos of Monday's speech on their phones. "Let's build a better world," their placards say, "before it's too late."