Nevada cave reveals 580,000 years of dramatic climate swings

The climate of the desert Southwest looks calm at first glance, but its past tells a different story.

Long before cities and highways, this part of the country flipped between cooler, wetter stretches and hotter, drier ones. Those shifts shaped the plants, water supplies and landscapes that helped life hang on in a tough place.

A rare natural record tucked inside a Nevada cave now shows how those changes played out over the last 580,000 years.

The findings offer clues about what the future might bring to a region that already feels stretched thin.

An unusual archive

Deep below the surface, a tall deposit of calcite built up grain by grain. Each layer trapped hints of past temperatures and rainfall.

This kind of archive is unusual in dry regions, where wind and heat erase much of the evidence scientists usually rely on.

The study, led by researchers from Oregon State University, was focused on a narrow feature known as Devils Hole II. It is filled with groundwater that has been flowing through the rock for hundreds of thousands of years.

Climate lessons from a deep cave

The researchers descended about 65 feet through a tight shaft to reach the lowest chamber. They drilled a core of calcite about 3 feet long from the cave wall.

“This meter-long core gives you a record of how climate has changed over half a million years.” said Professor Kathleen Wendt, the study’s lead author.

“What we see over this time span are glacial periods, when Nevada was cooler and wetter, followed by interglacial periods, when Nevada was hot and dry, like what we’re experiencing today.”

“But midway through those interglacial periods, the available groundwater dropped sharply and vegetation plummeted.”

Caves hold a record of climate

Professor Wendt pointed out that cores of ancient ice collected in Antarctica and Greenland have been long used to study climate history.

However, it is difficult to find land-based archives that record past climate – especially in places that are dry and arid, like the southwest United States, she noted. “Caves are one place we can look for these records.”

Devils Hole is not a typical cave. It is more like a tall fracture in the Earth where water leaves hard mineral deposits along the rock. Professor Wendt compared it to the hard water crust that forms inside old plumbing over time.

Shifting storms and falling vegetation

Study co-author Christo Buizert is an associate professor in OSU’s College of Earth, Ocean, and Atmospheric Sciences.

“Today, the bulk of the rainstorms coming off the ocean hit the Pacific Northwest, but during ice age periods, that same belt of rainstorms would land a lot further south.” said Buizert.

“That tells us these storm systems can move up and down the coast, and they can shift quickly and dramatically.”

When winter rain reaches the region, it helps refill the aquifer. The study shows that when groundwater dropped during hot stretches, plant growth also sank.

This timing helped the researchers understand how water, temperature and vegetation connect in this part of the country.

The future of a stressed region

“This raises questions about what we might expect in this region in the future as climate continues to change,” Buizert said.

“This part of the world is already on the cusp of livability with high summer temperatures and limited water resources.”

The long record inside the Nevada cave does not predict exact outcomes. It does show that this environment has swung sharply before.

Those swings had serious impacts on water and plants. The past is not a perfect guide, but it can warn us about what happens when heat rises and water thins out.

Valuable climate record in a cave

The record from the cave also reminds researchers that change does not need centuries to matter.

Past warm periods showed real drops in water and vegetation within spans that would overlap a human lifetime. That scale makes the story more immediate, not just ancient history.

Scientists say the value of this core is its ability to show how tightly water, heat and life are linked in the Southwest.

As the region warms, that link becomes the key to understanding which landscapes can endure and which may struggle to recover.

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