John Francis is an unusual pilgrim.

In 1971, the son of West Indian immigrants witnessed an oil spill in San Francisco. The environmental disaster changed his life. He abandoned the use of motorized vehicles and began walking thousands of miles. Within a few months he also had taken a vow of silence, which he observed for 17 years.

“I have begun a pilgrimage, a lifetime around-the-world walking and sailing journey, as part of my education to raise environmental consciousness and promote earth stewardship and world peace,” Francis writes in the opening to his book, “Planetwalker: How to Change Your World One Step at a Time.”

Francis, a 58-year-old California resident, will be in Lawrence this week to talk about his experiences.

“Walking is a way of knowing,” said Francis, who has family in Lawrence. “It’s just another way that we have at our disposal to know things and to learn things.”

Francis will speak at 6:30 p.m. Saturday at Sunflower Outdoor & Bike Shop, 802 Mass. He’ll play the banjo, talk for about an hour, and sign copies of his book.

Francis’ life-changing moment came when he witnessed the 1971 oil spill. An environmental crisis, he said, is “a crisis of mind and spirit” that involves more than just animals, plants and the land.

In his book, he describes watching the clean-up effort in the bay and wanting to do something to help — and simultaneously wanting to simplify his life.

Shortly after that, he started walking and stopped riding in cars. He eventually walked through Montana, South Dakota, Minnesota, Wisconsin and Indiana to Washington, D.C. — though he missed Kansas on the way. From 1972 until 1995, he didn’t take a single ride in a car, train or airplane, he said.

Shortly into his journey, Francis realized that his decision to walk everywhere didn’t seem like enough of a change.

“Something in the way I talk, argue, and defend walking is troubling,” he wrote in his book.

So he took a vow to stop talking — a vow he kept until Earth Day in 1990.

When he broke his silence, he was surrounded by friends and family members. His first words were, “Thank you for being here.”

A learning experience

The two major changes to his life — walking and not speaking — he said, helped him to earn a doctorate in land resources from the University of Wisconsin and to write a dissertation on oil spills.

“For me the walking really grounded me to allow me to learn,” he said. “The silence really helped me … to learn about myself but also to listen. If there’s one way you want to learn about the environment, you can fly over it, you can drive through it, and you get something through that. I’m not going to say walking is better, but it’s different.”

As word of Francis’ efforts spread in the early 1990s, he was appointed a goodwill ambassador for the United Nations’ environmental program and was asked to help write oil-spill regulations for the U.S. Coast Guard.

Francis, who is married with a son, visits Lawrence often. His mother-in-law is Lawrence resident Marty Smith, wife of the late Lynwood H. Smith, who was well-known as a physician for the Mayo Clinic in Rochester, Minn., before his death in 2002.

While in Lawrence in December, Francis walked into Sunflower and asked whether they wanted to buy copies of his book to sell at the store.

Assistant manager Charlie Shrimplin said she was immediately struck by Francis’ story, and Francis agreed to come back to the store and sign copies.

Shrimplin said she hoped Francis’ upcoming speech would “excite and inspire” people to spend time outdoors and to think about the environment.