Greta sails in a high-tech boat to a UN meeting against climate change. This luxury (and obviously exciting) adventure causes more GHG emissions than a business flight, since the crew of the race boat has to fly intercontinentally. More importantly, there is no need to physically travel to such meeting, since there is internet. A saint would be supposed to show this by example. Rather than that, Greta has become the Mascot of the movement and her arrival in New York almost looked like the Pope visiting a catholic country.