Greta Thunberg has reached adulthood as she turned 18 on January 3. The Teen climate activist who became famous for striking school as a protest against lack of government and organisational action to mitigate climate change, is a world renowned personality who has spoken at the World Economic Forum at Davis and also sailed the Atlantic to highlight climate change. Here are some quotes that have struck a chord with those working to manage global warming as well as inspiring those of her generation.