Greta Tintin Eleonora Ernman Thunberg (born 3 January 2003) is a Swedish environmental activist who is known for challenging world leaders to take immediate action for climate change mitigation. She speaks fluent English, and most of her public interactions are in English. Thunberg initially gained notice for her youth and her straightforward and blunt speaking manner, both in public and to political leaders and assemblies, in which she criticizes world leaders for their failure to take what she considers sufficient action to address the climate crisis.