“It’s insane that a 16-year-old has to cross the Atlantic in order to take a stand, but that’s how it is. It feels like we are at a breaking point. Leaders know that more eyes on them, much more pressure is on them, that they have to do something, they have to come up with some sort of solution. I want a concrete plan, not just nice words.”

— Greta Thunberg

Since Ms. Thunberg’s first solo vigil outside Sweden’s parliament a year ago, almost to the day, the harsh glare of the media spotlight has proved a mixed blessing. For every believer like 14-year-old Manhattan climate activist Alexandria Villasenõr, there have been critics like the influencer for the website Spiked who mocked the “apocalyptic dread in (Ms. Thunberg’s) eyes” and the far-right conservative MP in the French parliament who, ahead of her address last month, labeled her the “Justin Bieber of ecology” and a “prophetess in shorts.”

Leaving aside the fact that, based on her past public pronouncements, she’d be only too happy to cultivate a following as widespread and culturally diverse as that which follows Mr. Bieber, she’s proved herself more than a match for her doubters — doubters, it must be said, who include some truly nasty, dangerous characters such as followers of Germany’s far-right Alternative für Deutschland (AfD) ahead of the EU elections in May.

None of this was going to change when she finally stepped foot in New York City this past week, having crossed the Atlantic in a 16-day sea voyage aboard a small, carbon neutral solar powered racing yacht owned by Prince Albert of Monaco.

Human activity is a prime driver behind global warning, according to the UN’s Intergovernmental Panel on Climate Change. This conclusion is shared by 97% of actively publishing climate scientists, according to a 2016 study of peer-reviewed journals; the other 3% are climate scientists who appear on Fox News.

Ms. Thunberg was reportedly trembling and unsteady on her legs when she finally stepped onto dry land after 16 days at sea — she’s only 16, after all — but, having arrived in Trumplandia, if she was going to be intimidated, she didn’t show it. Not so long ago, Trumplandia was the land of the free and the home of the brave, after all.

The UN Climate Summit awaits, and Ms. Thunberg

will be there at the invitation of UN Secretary-General António Guterres, who tweeted Thursday, “The determination and perseverance shown during your journey should embolden all of us taking part in next month’s #ClimateAction Summit. We must deliver on the demands of people around the world and address the global climate crisis.”

Here’s the thing, though: Ms. Thunberg is well past the point of settling for pomp and pageantry. She made as much clear, during a brief appearance before the media later that day.

The wildfires that have ravaged the Amazon rainforest in recent weeks, she told reporters, are a “clear sign we need to stop destroying nature.”

Crossing the Atlantic by solar-power yacht, as opposed to flying, sends a signal that “the climate crisis is a real thing.

“I want to thank everyone . . . who is involved in this climate fight, because this is a fight across borders, across continents.”

She a realist, not a fantasist or ideologue. Asked if she could make the current leader of the United States listen, she replied with a simple, flat, “No.”

“I’m not that special,” she added. “I can’t convince everyone. I’m just going to do what I want to do and what will have most impact.”

If she had a message for Mr. Trump, she added, “My message for him is to listen to the science, and he obviously doesn’t do that.”

Several of Ms. Thunberg’s critics have mocked her for her Asperger’s, a form of autism, but she owned it and threw it right back at them.

Asperger’s has allowed her to “see things from outside the box,” she explained to BBC News.

“If I would’ve been like everyone else, I wouldn’t have started this school strike.”

Oh, and one other thing. She has been nominated for the 2019 Nobel Peace Prize. ‘nuff said.