Environmental activist Greta Thunberg says she will take her message to America the old-fashioned way: by boat. The Swedish 16-year-old wrote on Twitter Monday that she and a crew will sail across the Atlantic Ocean next month. She plans to be in New York City in September for a United Nations climate meeting. Later in the year, she will travel to Chile for the UN’s yearly climate conference. Thunberg will sail on a high-tech boat that produces zero carbon electricity. It will leave from Britain in the middle of August. Thunberg spoke with The Associated Press before she announced her plans. She said she spent months researching how to travel to the United States without using a plane. Thunberg mostly avoids flying because planes release high amounts of greenhouse gases.