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Deep in the state of Sierra mountain range, enormous glaciers are disappearing and projected to dissolve entirely by the start of the next century, leaving ice-free peaks for the initial occasion in human history, new research has found.

Age-Old Origins of Sierra Nevada Ice Masses

The range's glaciers are older than earlier understood, tracing back tens of thousands of years, with some as old as the most recent glacial period, according to an article published recently.

“Our pieced-together ice age record shows that a future glacier-free Sierra Nevada is without precedent in human history since documented peopling of the Americas around twenty thousand years ago,” the article declares.

Worldwide Risk to Glaciers

Glaciers around the world are at risk during the climate crisis. A study published in May of this year determined that nearly 40% of glaciers are destined to melt because of global heating. If such heating rises by 2.7 degrees Celsius, which the world is currently on track for, as many as seventy-five percent will vanish, leading to ocean level increase and large-scale relocation.

Throughout the American west, glaciers have shrunk significantly since they were first documented in the late 19th century, according to the report.

Concentration on Key Glaciers

The recent study focuses on several Sierra Nevada glaciers – the Conness, Maclure, Lyell and Palisade ice sheets – that are some of the largest and probably oldest in the mountain chain. Their longevity amid global heating makes them “bellwethers” for examining glacier disappearance in the west, the article states.

Study Techniques and Findings

Researchers examined recently exposed bedrock around the ice formations and took samples to determine how extensively the region was covered by glacial ice. They found that the glaciers have covered swaths of the range for much longer than previously known – since prior to people occupied North America.

California’s glacial sheets reached their peak extents as long ago as thirty thousand years ago, the study's researchers stated, and one of the glaciers researchers looked at is thought to have expanded seven thousand years ago, sooner than previously believed. The loss of ice formations, for the first time in recorded history, demonstrates the profound impacts of the climate crisis, one author of the investigation said.

Ecological and Representational Consequences

“We’ll be the initial ones to witness 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 glaciers are concrete. They’re iconic features of the Western U.S..”