Münter, whose work as a photo double for actress Catherine Zeta-Jones funded her racing career, this week became a patron of UK-based charity Population Matters that aims to address the growing world population by promoting smaller families.
The American sportswoman, once named one of the top 10 female race car drivers by Sports Illustrated, said population growth was one of the world's biggest threats and women should not be judged negatively for choosing not to have children.
The United Nations estimates that the world population is growing by 83 million a year, with the number of people on the planet expected to hit 9.8 billion in 2050 from 7.6 billion now.
"Not having a child has been the biggest way for me to reduce my impact on the planet," Münter, 44, told the Thomson Reuters Foundation in a phone interview on Wednesday.
"If you look at the numbers, the earth is finite, and the human race cannot keep growing infinitely with only so many resources."
Others patrons at the charity include TV naturalist David Attenborough, English actress Susan Hampshire, and British primatologist Jane Goodall.
Describing herself as a "vegan, hippy chick" on the Population Matters website, Münter said women today were under too much pressure to have families, something she has fought since she was at college and agreed with her husband.
A lawmaker in Japan recently came under fire on social media after saying women should have at least three children as women without children risked becoming financial burdens on the state.
"We need to normalize choosing being child-free," said Münter, calling for more education on birth control.
United Nations figures show on average women globally have 2.5 children but Africa remains the region with the highest fertility at 4.7 children per woman.
"Where women and girls have economic empowerment, education and freedom, they choose to have smaller families," Population Matters said on its website.
"When family sizes are smaller, that also empowers women to gain education, take work and improve their economic opportunities."
Reporting by James Honigsberger for the Thomson Reuters Foundation.