Recently, Swedish teen and climate activist Greta Thunberg crossed the Atlantic Ocean on a zero-emissions sailboat to attend the 2019 UN Climate Summit being held in New York City. According to the New York Associated Press, as the social-media-savvy teenager approached New York Harbor, she tweeted, "Land!" Greta refused to fly because of the carbon cost of plane travel. A 2018 study indicated that because of cloud and ozone formation, air travel may trap two to four times more heat than caused by emissions of carbon dioxide and other greenhouse gases. In contrast, the onboard electronics of the sailboat Greta traveled on were powered by solar panels and underwater turbines. Inscribed on the boat’s sail are the words: UNITE BEHIND THE SCIENCE.