John Muir's significant contributions to environmental conservation include his advocacy for national parks and preservation of wilderness areas. As a naturalist and writer, Muir co-founded the Sierra Club, playing a pivotal role in the conservation movement. His passionate writings about the beauty of nature inspired public interest in protecting wild landscapes. Muir’s efforts were instrumental in the establishment of national parks like Yosemite and Sequoia. His legacy endures as a foundational figure in ecology and environmentalism, emphasizing the intrinsic value of nature and the need for its preservation.