Greta Thunberg refused to fly across the Atlantic to attend United Nations climate summits.

After voyaging thousands of miles across the Atlantic Ocean, climate activist Greta Thunberg made landfall in the United States on Wednesday afternoon. The 16-year-old began the journey two weeks ago to reach the United Nations climate summit in New York without producing any carbon.

Amid a rising sun and pale yellow clouds, her boat floated near New York, in a picture she posted to Twitter on Wednesday morning. The sail reads the words, "Unite Behind the Science," Thunberg's call to action. When she docked at the North Cove Marina near the World Trade Center, Thunberg was met with raucous cheers and chants of "Greta! Greta!" She carried a sign that read "Skolstrejk för klimatet," or "School strike for the climate."

Addressing dozens of supporters moments later, she called her voyage "overwhelming."

"The ground is still shaking for me," she said. "The trip was very surprisingly good. I did not feel seasick once."

Asked what she would miss about being in the ocean, the teen reminisced about the quiet. "To sit for hours and just stare at the ocean, not doing anything, that was great," Thunberg said. "And of course to be in the wilderness, the ocean, and see the beauty of it."

The Swedish activist, who reached worldwide fame after encouraging young people worldwide to strike from school and raise awareness about climate change, set sail in mid-August. She declined to fly because of the levels of emissions released during air travel.

Searching for the best way to get to New York, she decided on the Malizia II, a carbon-neutral sailboat captained by Boris Herrmann. Thunberg made the trip with her father, Svante, as well as documentary filmmaker Nathan Grossman and the head of the yacht's racing team, Pierre Casiraghi.

Stretching 60 feet in length, the boat is ultraefficient, equipped with solar panels and underwater turbines that generate electricity. The boat also measured ocean surface temperature as it passed through the Atlantic.

Thunberg packed books and eight journals for the trip, the New York Times reported, and said she planned to eat freeze-dried meals and use a bucket to go to the bathroom. She expressed nervousness before and after the journey.

"Whether it's seasickness or homesickness or just anxiety or I don't know," she told the Times. "I don't know how tough this journey will be."

Thunberg documented each day of the trip on Twitter. In one video, ocean water sprays up against the Malizia II as the crew passes by Nova Scotia.

The seas were rough at times, and so was the criticism. Thunberg faced attacks online during the journey. The Washington Post's Claire Parker reported that the attacks were "ruthlessly derisive," as others cheered her on.

Arron Banks, a British businessman who has bankrolled the Brexit campaign, mused on Twitter about a calamity befalling the teenage voyager.

"Freak yachting accidents do happen in August . . ." he wrote.

Banks' comments drew a swift backlash from British politicians and celebrities. Green Party Member of Parliament Caroline Lucas, whose encouraging words to Thunberg prompted Banks' tweet, said the Brexit-backer's message "makes me sick to the stomach."

"I have made a formal complaint to Twitter," she wrote.

After reaching the shore Wednesday, Thunberg detailed the journey and reiterated her concerns about the environment. She discussed deforestation, greenhouse gases and the fires in the Amazon rainforest, which she called "hard to imagine."

"The climate and ecological crisis is a global crisis and the biggest crisis humanity has ever faced. If we don't manage to work together and cooperate, and work together despite our differences, we will fail," she said. "We need to stand together and support each other and take action, or otherwise it might too late. Let's not wait any longer, let's do it now."

When asked if she had a message for Trump, Thunberg offered a candid response: "Listen to the science, and he obviously doesn't do that."

The activist plans to attend climate summits in New York and Santiago, Chile, which she also hopes to attend using the most sustainable methods of transit available, she said.

She has continually spoken out about the world's changing climate. Last year, she spoke at the U.N. COP24 conference, telling leaders they had ignored issues surrounding the climate.

"You say you love your children above all else, and yet you are stealing their future in front of their very eyes."