Fresh off her detention in Germany, Greta Thunberg was in Davos Thursday to issue an open letter to fossil fuel company CEOs demanding that they immediately halt opening new extraction sites for oil, gas or coal, signed alongside Vanessa Nakate, Helena Gualinga, and Luisa Neubauer. The environmental activists appeared on a panel with the International Energy Agency’s (IEA) Executive Director, Fatih Birol.

Thunberg called out delegates in Davos, who she said were “mostly fueling the destruction of the planet,” and “at the very core of the climate crisis,” such as those who have invested in fossil fuels.