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Deep in California’s Sierra Nevada, enormous glaciers are vanishing and projected to melt away completely by the start of the next century, resulting in ice-free peaks for the initial occasion in recorded human existence, new research has found.

Ancient Origins of Sierra Range Ice Masses

The mountain range’s glaciers are older than previously known, dating back many thousands of years, with a few as ancient as the most recent glacial period, according to a report released last week.

“Our pieced-together ice age record shows that a future glacier-free Sierra Nevada is unprecedented in the history of humankind since documented settlement of the Americas around twenty thousand years ago,” the article states.

Worldwide Threat to Glaciers

Glaciers globally are at risk amid the climate emergency. A study released in May of this year determined that almost forty percent of glaciers are doomed to melt because of global heating. If this warming increases by 2.7C, which the planet is currently on course for, as many as 75% will disappear, causing sea level rise and large-scale relocation.

Across the Western United States, glaciers have shrunk substantially since they were first documented in the late 19th century, according to the report.

Focus on Key Glaciers

The new research focuses on four Sierra Nevada glaciers – the Palisade, Lyell, Maclure and Conness ice sheets – that are some of the biggest and probably oldest in the mountain chain. Their durability amid climate warming makes them “bellwethers” for examining ice loss in the western region, the study states.

Research Methods and Results

Researchers looked at recently exposed base rock around the ice formations and collected specimens to ascertain how extensively the area was blanketed by glacial ice. They found that the ice masses have covered swaths of the range for much longer than previously known – since prior to people inhabited North America.

The state's glacial sheets attained their peak extents as early as 30,000 years ago, the article’s authors wrote, and one of the ice bodies experts studied is thought to have grown 7,000 years ago, sooner than previously believed. The loss of glaciers, for the initial time in recorded history, demonstrates the profound impacts of the climate change, a researcher of the investigation said.

Environmental and Symbolic Impact

“We’ll be the first to see the glacier-less summits,” said the study's lead researcher, the study’s lead author. “This has environmental implications for plants and animals. And it’s a symbolic loss. Global warming is very abstract, but these ice masses are tangible. They’re iconic features of the American West.”