Even before climbing star Alex Honnold’s stunning “free solo” ascent of Yosemite’s El Capitan in 2017, rock climbing was gaining a foothold. Now, with its debut at this year’s Tokyo Olympics, the once niche sport is set to reach new heights.
Yet the popularity of rock climbing and its sister sport, bouldering (where climbers scramble up large rocks without the use of ropes or harnesses), is raising questions about the damaging environmental effects of climbing chalk—a ubiquitous and essential climbing tool.
Made from magnesium carbonate, climbing chalk is the same substance that gymnasts and weightlifters use to improve their grip on bars and weights. In fact, it was first introduced to rock climbing in the 1950s by John Gill, who was a gymnast in college before he turned his attention to bouldering. Since then, amateur and professional climbers alike have come to depend on the chalk’s desiccating and friction-inducing properties—and have been leaving streaks of the stuff on rock faces around the world.
The resulting “chalk graffiti” has become so bad in the United States that parks are beginning to restrict its use. Utah’s Arches National Park allows only colored chalk that mostly matches rocks, while Colorado’s Garden of the Gods National Natural Landmark banned all chalk and chalk substitutes. Native American tribes have declared areas under Indigenous control off-limits to climbers, not only because of unsightly chalk marks but also to preserve spiritually important areas.
Beyond the visual pollution, new research suggests chalk may be harming the flora that...