John Muir, a Scottish-American naturalist, author, and environmental philosopher, is widely regarded as the 'Father of Environmentalism' for his pioneering work in establishing national parks and advocating for the preservation of wilderness areas.

Rachel Carson, an American marine biologist and conservationist, published 'Silent Spring' in 1962, which brought widespread attention to the harmful effects of pesticides, especially DDT, on the environment and human health.

Wangari Maathai, a Kenyan environmental and political activist, founded the Green Belt Movement in 1977, which focused on planting trees and empowering women in rural communities to address environmental degradation and promote sustainable development.

Vandana Shiva, an Indian environmental activist and scholar, is known for her work with the Chipko movement, which began in the 1970s and involved villagers hugging trees to prevent their felling by loggers.

Greta Thunberg, a Swedish environmental activist, rose to prominence in 2018 when she began skipping school on Fridays to protest outside the Swedish parliament, demanding action on climate change. Her activism inspired the Fridays for Future movement, which has mobilized millions of young people worldwide.

Vandana Shiva, in addition to her work with the Chipko movement, is also known for her advocacy of sustainable agriculture, seed saving, and the protection of biodiversity. She has written extensively on the negative impacts of industrial agriculture and genetically modified crops.

Jane Goodall, a British primatologist and anthropologist, is renowned for her groundbreaking research on chimpanzees in the Gombe Stream National Park in Tanzania. Her work has provided valuable insights into the behavior, social structure, and intelligence of chimpanzees.

E.F. Schumacher, a German-born British economist and philosopher, is known for his work on sustainable development and the promotion of appropriate technology. His book 'Small Is Beautiful' (1973) advocated for a decentralized and self-reliant approach to economic development.

Amory Lovins, an American physicist and environmentalist, is known for his work on energy efficiency and renewable energy sources. He co-founded the Rocky Mountain Institute in 1982, which promotes sustainable energy solutions.

Paul Hawken, an American environmentalist, author, and entrepreneur, is known for his work on environmental education and the promotion of a sustainable lifestyle. He founded the Natural Capital Institute in 1993, which focuses on promoting sustainable business practices.

David Suzuki, a Canadian environmentalist, geneticist, and broadcaster, is known for his work on environmental issues and sustainable development. He is a co-founder of the David Suzuki Foundation, which works to protect the environment and promote sustainability.

Naomi Klein, a Canadian author and activist, is known for her work on climate change and the promotion of renewable energy sources. Her books, including 'This Changes Everything' (2014), have raised awareness about the economic and social implications of climate change.

Bill McKibben, an American environmentalist, author, and journalist, is known for his work on climate change and the promotion of renewable energy sources. He is a co-founder of 350.org, a global climate change movement.

Al Gore, a former Vice President of the United States, is known for his work on climate change and his role in the Intergovernmental Panel on Climate Change (IPCC). He shared the Nobel Peace Prize in 2007 for his efforts to raise awareness about climate change.

Christiana Figueres, a Costa Rican environmentalist and diplomat, is known for her work on climate change and sustainable development. She served as the Executive Secretary of the United Nations Framework Convention on Climate Change (UNFCCC) from 2010 to 2016.