Sierra Nevada's glaciers have existed as long as humans in North America. The ice mass in Yosemite National Park will soon disappear completely.
Glaciers naturally grow and shrink with climate variations. Human-caused global warming now melts them at unprecedented speeds. Burning fossil fuels drives this rapid change.
A new study in Science Advances reveals these California glaciers survived for at least 11,700 years. They likely formed over 20,000 years ago before humans settled the continent.
Researchers examined isotopes in bedrock recently exposed by melting ice. They also studied rocks and gravel pushed forward by glacial movement.
These glaciers could vanish entirely by the next century if emissions continue unchecked. The study confirms human activity now erases ancient natural features that withstood millennia of natural climate shifts. This represents a permanent alteration of California's mountain landscape that developed over thousands of years.