Swedish teen climate activist Greta Thunberg arrived Wednesday in New York City ahead of a United Nations summit after two weeks of sailing across the Atlantic Ocean on a fossil fuel-free vessel, the Malizia II.The 16-year-old tweeted Wednesday morning that the Malizia II had anchored off of Coney Island and that those aboard—including Thunberg\u0026#039;s father, a documentary filmmaker, and sailors Pierre Casiraghi and Boris Herrmann—would come ashore as early as mid-afternoon once they cleared customs and immigration.Their arrival prompted celebrations on social media, with climate activists and organizations welcoming Thunberg and the others to the United States.Welcome to North America @GretaThunberg! Looking forward to fighting the #ClimateCrisis with you here and abroad. #ClimateAction https://t.co/Vc7FdEoJOX— UN Environment in North America (@UNEnvironmentNA) August 28, 2019\u0022Welcome to New York, Greta Thunberg! Looking forward to meeting you again, this time at the U.N. Youth #ClimateAction Summit!\u0022 tweeted Jayathma Wickramanayake, the U.N. secretary-general\u0026#039;s envoy on youth.Author and activist Naomi Klein wrote on Twitter, \u0022Oceans of love and gratitude await you Greta Thunberg!\u0022\u0022So good to have you on these shores!\u0022 tweeted 350.org co-founder Bill McKibben. \u0022Your journey is a symbolic reminder of the ways we need to work together across every ocean!\u0022Before the sailboat left the United Kingdom two weeks ago, Thunberg told The Associated Press that \u0022by this journey I hope to increase awareness among people to spread information and communicate the science about what is really going on so people can understand what is really going on with the climate and ecological crisis.\u0022In a message retweeted by Thunberg, meteorologist and writer Eric Holthaus wrote on Twitter Wednesday: \u0022You don\u0026#039;t need to spend two weeks on a boat to do your part to avert our climate emergency. You just need to do everything you can, with everyone you can, to change everything you can.\u0022A friendly reminder: You don’t need to spend two weeks on a boat to do your part to avert our climate emergency.You just need to do everything you can, with everyone you can, to change everything you can.If we all did that, my loves, it would be enough.— Eric Holthaus (@EricHolthaus) August 28, 2019Thunberg has documented her journey on social media, tweeting updates on the Malizia II\u0026#039;s location and sea conditions, details about the zero-emissions boat, and even photos of her now-famous school strike for climate poster. According to her tweets, the crew had initially expected to arrive in New York City on Tuesday but were delayed by rough seas south of Nova Scotia.The activist—who was nominated for a Nobel Peace Prize after her solitary protests outside the Swedish parliament helped spark a global movement of youth striking from school to demand bold climate action—is expected to speak at a summit organized by U.N. Secretary-General António Guterres, which kicks off Sept. 23.The primary aim of the U.N. summit, based on the goals of the 2015 Paris climate agreement, is for world leaders to establish \u0022concrete, realistic plans to enhance their nationally determined contributions by 2020, in line with reducing greenhouse gas emissions by 45 percent over the next decade, and to net zero emissions by 2050.\u0022During Thunberg\u0026#039;s trip to the United States, she also is expected to participate in protests slated to start Sept. 20 as part of a Week of Action to pressure U.N. member states to make systemic changes that will reduce their planet-heating emissions, such as transitioning to renewable energy.Thunberg will continue her travels for climate action through the winter. She is scheduled to participate in the COP25 climate conference in Santiago, Chile, in December.