In August, Thunberg, who refuses to fly, sailed across the Atlantic Ocean from Plymouth, England, to New York in a zero-emissions boat to take part in a UN climate summit. The voyage lasted 15 days, from Aug 14 to 28.

However, France 24 reported that several crew would fly to New York to take the yacht back to Europe.

In September at the 2019 UN Climate Action Summit in September, Thunberg told world leaders: "You have stolen my dreams and my childhood with your empty words. And yet I'm one of the lucky ones. People are suffering. People are dying. Entire ecosystems are collapsing. We are in the beginning of a mass extinction. And all you can talk about is money and fairytales of eternal economic growth. How dare you!"

The young environmental activist has won support across the world. In February, 224 academics signed an open letter of support stating they were inspired by the actions of Thunberg and the striking school children in making their voices heard.

United Nations Secretary-General António Guterres also endorsed the school strikes initiated by Thunberg, admitting, "My generation has failed to respond properly to the dramatic challenge of climate change. This is deeply felt by young people. No wonder they are angry."

However, Thunberg and her campaign have also been criticized by many people.

Russian President Vladimir Putin criticized her as "poorly informed": "No one has explained to Greta that the modern world is complex and different and people in Africa or in many Asian countries want to live at the same wealth level as in Sweden."

"This transformation of Thunberg by publications like Time from activist to influencer has gone a long way in voiding her politics, instead putting focus on her personality," The Independent wrote.