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Deep in California’s Sierra Nevada, massive glaciers are vanishing and expected to dissolve entirely by the start of the next century, leaving ice-free peaks for the first time in recorded human existence, new research has found.

Ancient Origins of Sierra Range Ice Masses

The range's ice sheets are older than earlier understood, dating back many thousands of years, with a few as old as the last ice age, according to an article published recently.

“Our pieced-together glacial history indicates that a future glacier-free Sierra Nevada is without precedent in human history since documented settlement of the Americas around twenty thousand years ago,” the article states.

Worldwide Threat to Glaciers

Ice masses globally are under threat during the climate crisis. A study released in May of this year found that nearly 40% of glaciers are destined to thaw because of global heating. If this warming increases by 2.7 degrees Celsius, which the planet is presently on course for, as up to 75% will disappear, causing sea level rise and large-scale relocation.

Throughout the Western United States, glaciers have diminished substantially since they were initially recorded in the late 19th century, according to the article.

Focus on Major Ice Bodies

The new research focuses on four Sierra Nevada glaciers – the Palisade, Lyell, Maclure and Conness ice sheets – that are some of the largest and likely most ancient in the range. Their durability amid climate warming makes them “bellwethers” for studying ice loss in the west, the study states.

Study Techniques and Findings

Scientists examined recently exposed base rock around the glaciers and took samples to determine how extensively the region was blanketed by ice. They found that the glaciers have enveloped swaths of the range for far longer than previously known – since before humans inhabited North America.

The state's glaciers attained their peak extents as long ago as thirty thousand years ago, the study's researchers wrote, and one of the ice bodies researchers looked at is believed to have expanded 7,000 years ago, sooner than once thought. The disappearance of glaciers, for the first time in human history, shows the profound effects of the climate change, a researcher of the study said.

Environmental and Representational Impact

“We’ll be the initial ones to see the glacier-less summits,” said Andrew Jones, the principal investigator. “This has ecological ramifications for plants and animals. And it’s a representational decline. Climate change is highly intangible, but these ice masses are concrete. They’re iconic features of the Western U.S..”