For the first time in over 11,000 years, the iconic granite peaks of the Sierra Nevada may soon stand without their historic glaciers. New research reveals that glaciers in and around Yosemite National Park have persisted continuously since the last Ice Age, but now face imminent disappearance.
Scientists from the University of Wisconsin, the National Park Service, and other institutions analyzed rocks near glacier edges, confirming that ice has remained since humans first arrived in North America. The study highlights that a future without Sierra glaciers would be unprecedented in human history.
Since the late 1800s, California’s glaciers have already lost between 70 and 90 percent of their volume. Yosemite’s Lyell Glacier, once extensively studied by John Muir, has shrunk by approximately 95 percent and is now divided into two inactive ice patches.
These glaciers are vital to the Sierra’s water systems. During late summer, after the snowpack melts, their meltwater sustains alpine streams and major rivers like the Tuolumne. As glaciers vanish, many waterways risk running dry during the hottest months.
The region has seen summer temperatures rise by about 3.6°F over the past century, accelerating glacier retreat. The loss of these ancient ice masses marks a profound shift in the Sierra Nevada’s natural balance and underscores the rapid impact of climate change on even the most enduring landscapes.
