Aboard a tiny pontoon, Elliott rode low to guide a rigid plastic tube vertically underwater while her colleague Josh Bregy raised a metal pole up and down above her helmet-clad head— ding! ding! ding! – sink the pipe deep into the bottom of the lake.
After hours spent on the water, they hoisted a 1.5 meter cylinder from the bottom of the lake. Elliott searched among the patches of mud for what he was looking for: a layer of sand, the potential remnants of a deadly storm that hit the Florida Panhandle.
“It’s a beautiful example of a hurricane layer,” she said, she ran her finger over the clear tube.
This wet, dirty work is part of a field of research called paleotempestology, the study of ancient hurricanes. A growing and relatively new science is trying to understand the storms that hit this and other coasts before people began recording the weather with modern instruments.
What scientists have found so far in this ancient mud offers a warning. Paleotempestologists sifting through the sediment noted a period when intense storms hit the coast more often than current records indicate. Their work suggests that the oceans are capable of producing hurricane seasons far more relentless than anything modern society has yet seen.
Now, by burning fossil fuels and pumping heat-trapping gases into the air, the world risks recreating those stormier conditions. Meteorologists have already predicted that this year’s hurricane season, which began on June 1, could be among the worst in decades. Hurricane Beryl, which exploded into a dangerous Category 4 hurricane on Sunday, is forecast to spread across the Caribbean this week.
If the past is “any indication of what we’re going to see,” Elliott said, “our coastal zones are really vulnerable.”
Hunt for ancient hurricanes
In 1989, Louisiana State University professor Kam-biu Liu gave a lecture on ash layers left on the bottom of lakes by volcanic eruptions. Student Miriam Fearn asked if scientists also see tracks left by hurricanes.
“That got me thinking. I said, ‘Of course it should be doable,'” Liu said. That summer, he and Fearn found a layer of sand deep beneath an Alabama lake left by a 1979 storm.
Paleotempestology was superseded after Category 5 Hurricane Andrew hit the Bahamas, Florida, and Louisiana in 1992, killing dozens of people and causing billions of dollars in damage. The insurance industry that financially supports domestic insurers and other insurance companies, pumped money into prehistoric hurricane research to better understand the risk of major storms.
“They really put their money where their mouth was and really started the field,” said Jeff Donnelly, another early ancient hurricane researcher at the Woods Hole Oceanographic Institution.
There is little climatologists can do to predict how hurricane patterns will change in response to rising temperatures: roughly 170 years of instrumental data, the blink of an eye in Earth’s history. Paleotempestology holds the promise of extending the storm record by thousands of years and painting a more complete picture of how bad hurricanes can be.
When a strong hurricane makes landfall, the water hits the beaches and carries waves of sand inland. If the lake is located right next to the shore, this material will wash into it and settle on the bottom. By measuring the radiocarbon in these layers, paleotempestologists can determine when the storm struck.
Over time, this coarse beach sand deposited by storms becomes encased in mud or sandwiched between layers of finer sand. In general, the more intense the storm, the coarser the sand because more energy is needed to wash away the heavier grains.
Spotting a hurricane sand layer among a pile of other sand can be difficult — like “looking for hay in a haystack,” Elliott said.
Elliott knows persistence. She grew up in Michigan helping her father build houses during summer vacations while studying geology in college. She said she had tense conversations about climate change with her more conservative father.
But she recently took the time to walk him through the data and answer his questions. “We just sat down and talked about it,” she said. “And now we’ve moved to a place where he’s at least more willing to have a conversation and acknowledge that things are changing.”
Here at Campbell Lake, in Topsail Hill Preserve State Park, Florida, only a thin ridge of blinding white sand separates the freshwater body from the Gulf of Mexico. This is one of the few places in the world with coastal dunes. Elliott, an aspiring researcher of ancient hurricanes, thought it was the perfect place to look for signs of ancient storms.
“The coastal lakes are our favorite place,” she said.
After sinking the tube into the lake bed, Elliott and Bregy, a scientist at Clemson University, took turns cranking the winch and hand-pulling the cylinder to retrieve a bit of the lake’s valuable sediment.
“This is better going to be mud,” Bregy said. “Go on, go on, go on,” Elliott urged. “He needs to get out. The first, half-foot core contained a layer of sand from a relatively recent storm, likely Hurricane Opal in 1995.
To find the older storms, the team had to dig deeper into the bottom of the lake—and into the past. With no motor for the pontoon, Elliott and Bregy relied on their college students in a kayak and canoe to pull it across the nearly 100-acre lake.
Away from the shady pines along the edge of the lake, a small army was pulling a pontoon toward the center of the lake. Lake. Another group of students sat on the bank — looking for alligators.
“Watch your head,” Bregy said before clinking clinking another hollow plastic tube into the bottom of the lake. Exhausted, he began to imagine what he would eat that evening. “I’m going to have ice cream tonight,” he said. “I’m going to get some strawberries.”
The other two cores were larger: about 3 feet and 13 feet long. The longest probably dates back more than 10,000 years, Bregy said. Their chalky smell suggested they contained marine microfossils rich in calcium carbonate, which would tell scientists which layers washed up from the ocean.
As soon as Elliott and Bregy were back on dry land, they stabbed.
Other sediment cores along the Gulf Coast reveal periods of intense hurricane activity in the region — worse than what we see today. It lasted for centuries before ending abruptly about 600 to 800 years ago.
What caused storms to rage and then subside? One theory is that a change in the position of a high-pressure system over the Atlantic called the Bermuda High may have pushed the storm away from the Gulf Coast and toward the East Coast. This would explain why New England lakes are seeing an increase in storms right after a drop in hurricane activity along the Gulf Coast.
Another factor is a current of warm water called the Loop Current that flows through the Gulf of Mexico. It once flowed close to the coast before sliding south into the Persian Gulf, a shift that lowered water temperatures and robbed storms of wind-stirred energy.
The fact that the surface temperature in the Persian Gulf is warming again today due to climate change worries those who study ancient hurricanes.
“What these records clearly show is that the climate system, outside of human intervention, is already able to adapt in a way that gives us activity that we haven’t seen in the last century,” Donnelly said. “The big question is what’s the likely outcome now that we’re actually turning the climate knobs ourselves?”
To find the answer, paleotempestologists look beyond the layers of sand for more evidence of hurricanes: they explore caves and look for drip deposits created by cyclonic rain, they search lakes for boulders of coral washed up by storms, they search libraries for newspaper clippings, logbooks and journal entries. hurricane bills.
“When you have different techniques and they work together,” Liu said, “then that might be the best approach.”
Much of Elliott and Bregy’s work focuses on tree rings. Hurricanes leave subtle marks on coastal trees—at least when they’re not downed—because their rings record extreme rainfall and saltwater flooding from the past.
Bregy goes to great lengths to find old wood, mining it from leftover stumps and even excavated coffins. He recently received a tetanus shot after being poked by a rusty nail while harvesting lumber in an old lot.
“The problem here in the eastern U.S. is that there’s been so much logging,” Bregy said. “It’s hard to find old living trees.
Back on shore, Elliott knelt down and used a power tool to cut one of the sediment cores in half. A thin strip of plastic curled as she guided the device down the length of the tube. Always ready to offer a lesson, she helped one of her students finish his work.
“Beautiful,” she said, praising his work. He paused, but she urged him on. “You’re good, you’re good.
A series of dark bands in the bisected sediment core may be hurricane layers, although only a thorough laboratory analysis will reveal the truth. Elliot and Bregy’s labs will search for marine fossils, measure the size of sand grains and analyze isotope levels to gauge the intensity of ancient storms and determine when they struck.
“This is the beginning of our work,” Elliott said.
At his hotel after a day of work on Lake Campbell, Elliott called his father. “‘What did you see? What did you learn?'” she remembered him asking.
Later in a phone interview, Elliott’s father, Tony Timmons, acknowledged that the climate is changing, though he “can’t wrap my arms around the fact that it’s all man-made.” If more scientists like his daughter looked into climate change, it might make people more likely to accept it.
“Em will explain things to me and it will be interesting to me and I understand that,” he said.
He added: “What he does is important.”