The girl in the video is Severn Cullis-Suzuki (born November 30, 1979 in Vancouver, British Columbia), a Canadian environmental activist, speaker, television host and author. She has spoken around the world about environmental issues, urging listeners to define their values, act with the future in mind, and take individual responsibility.
In 1992, at age 12, Cullis-Suzuki raised money with members of ECO to attend the Earth Summit in Rio de Janeiro. Along with group members Michelle Quigg, Vanessa Suttie, and Morgan Geisler, Cullis-Suzuki presented environmental issues from a youth perspective at the summit, where she was applauded for a speech to the delegates. The video has since become a viral hit, popularly known as “The Girl Who Silenced the World for 5 Minutes”. In 1993, she was honoured in the United Nations Environment Programme‘s Global 500 Roll of Honour.
SOURCES: Wikipedia and Youtube