Former Wisconsin Governor Gaylord Nelson died Sunday of cardiovascular failure at his home in Maryland.
The Clear Lake native is considered one of the world's top environmental leaders and the founder of Earth Day.
Local environmentalists say they already miss his ability to draw the masses toward a cause he felt so strongly about.
"It's unfortunate that today we lack that same thing," said Will Fantle of Northern Thunder.
"We need somebody on the national level with stature who can mobilize and rally people around environmental issues."
Fantle said that he attended the first Earth Day celebration as a high school kid in 1970, and that it played a role in his career choice.
Nelson was named the "4th Most Signifacant Wisconsinite of the 20th Century" in a poll of historians, done by the Milwaukee Journal-Sentinel in 1999.
He was 89 years old.