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    Why Hurricane Helene was so devastating

    A perfect storm of climate, geologic and geographic conditions have combined to make Hurricane Helene one of the most devastating storms to ever hit the United States. Days after it slammed into Florida’s Big Bend region on September 26 and traveled hundreds of kilometers inland, Helene’s destructive impact has continued to grow.

    Fueled by warm water in the Gulf of Mexico, which climate change made hundreds of times more likely, the tempest rapidly intensified offshore. By the time Helene came onshore as a Category 4 storm, its wind speeds surpassed 209 kilometers per hour (130 miles per hour) (SN: 9/27/24). More

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    A thousands-year-old log demonstrates how burying wood can fight climate change

    In 2013, Ning Zeng came across a very old, and ultimately very important, log.

    He and his colleagues were digging a trench in the Canadian province of Quebec, one that they planned to fill with 35 metric tons of wood, cover with clay soil, and let sit for nine years. The team hoped to show that the wood wouldn’t decompose, a proof-of-concept that burying biomass could be a cheap way to store climate-warming carbon. But during excavation, they unearthed a pristine, twisted log that was very old, older than anything they could have possibly produced in their experiment. More

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    A vital ocean current is stable, for now

    The ocean’s circulatory system may not be doing as poorly as previously thought.

    A vital ocean artery known as the Florida Current, a bellwether for the ocean’s ability to regulate Earth’s climate, has seemingly been weakening for decades. But that recent decline might not be quite as severe as suspected. The current has actually remained stable over recent decades, researchers report September 5 in Nature Communications.

    A previously reported decline in the flow had prompted speculations that a major system of ocean currents — known for regulating Earth’s climate — may have weakened recently due to human-caused climate change. Some researchers have suggested that the larger system, known as the Atlantic Meridional Overturning Circulation, or AMOC, could collapse sometime this century, dramatically cooling the northern hemisphere and raising the sea level along some Atlantic coastlines by up to 70 centimeters. More

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    A biogeochemist is tracking the movements of toxic mercury pollution

    One of the world’s richest biodiversity hot spots is Peru’s Madre de Dios, a region of the Amazon nestled at the base of the Andes mountains. When biogeochemist Jacqueline Gerson first traveled there in 2017, she found herself on a boat headed downstream through the forest. As the riverbanks passed by, she observed a scenic shift.

    At first, “it was beautiful, primary old-growth forest, lots of birds, lots of different wildlife,” says Gerson, a Ph.D. student at Duke University at the time. “Then, as I continued downstream … first you see these rocks,” she adds. “As you keep going, you see pile after pile after pile, and then you started to see some deforestation.”

    She was witnessing the signs of artisanal and small-scale gold mining. Unlike large-scale industrial operations with fleets of dump trucks and excavators, workers here use basic tools or their own hands to extract ore. These informal gold-mining efforts are so prolific in Madre de Dios that they support at least half of the region’s economy.

    In Madre de Dios, artisanal and small-scale gold miners tear down lush tracts of Amazonian rainforest to make way for mining operations, leaving behind mounds of sediment and pits that fill with water.Melissa Marchese

    But there is a price to that gain. The small-scale miners mix mercury into riverbank sediments that contain flecks of gold. This produces a gold-mercury amalgam that can easily be separated from the muck and then burned to isolate the gold. But that burning also releases fumes of mercury into the open air.

    For Gerson, now at Cornell University, illuminating how toxic contaminants flow through the environment is a calling. She studies how human activities contribute to these contaminants and alter their paths. More

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    How did dark matter shape the universe? This physicist has ideas

    At age 12, Tracy Slatyer felt sorry for a book. She read a newspaper article about how lots of people were buying A Brief History of Time by Stephen Hawking. “But then … nobody was actually reading it,” she says. “People were just leaving it on their coffee tables.”

    Determined to rectify this wrong, Slatyer obtained a copy and diligently read each page. The famous physicist’s popular text revealed to her “that math was in some sense an expressive language for describing how things really work,” she says. “That, to me, was exciting.” More

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    A materials scientist seeks to extract lithium from untapped sources

    Electric vehicles promise to help wean us off of fossil fuels, but they introduce a new problem: how to get enough of the lithium that EV batteries require (SN: 5/7/19).

    Materials scientist Chong Liu of the University of Chicago has some ideas. Existing technology can extract lithium only from sources with highly concentrated ions, like hard rocks or underground deposits of salty water called brines. Not only will those sources not be enough to meet demand, but mining them also comes with environmental consequences (SN: 3/15/22). More

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    Climate change could double U.S. temperature-linked deaths by mid-century

    Heat-related deaths in the United States are on the rise. But how bad will it be 20, 30 or 40 years from now? Scientists now have a clue.

    Currently, an estimated 8,000-plus deaths in the United States every year are associated with extreme temperatures, both hot and cold. Within the next few decades, that number could double or even triple, largely due to heat, researchers report September 20 in JAMA Network Open.

    “As the climate warms, the frequency, duration and intensity of heat waves is increasing. Understanding how this will impact our health is crucial,” Sameed Khatana, a cardiologist at the University of Pennsylvania, says. Our bodies are capable of bearing sweltering temperatures, but as temperatures rise, this ability is pushed to its limit (SN: 6/21/24). More

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    A neutrino mass mismatch could shake cosmology’s foundations

    As the youthful universe congealed under the pull of gravity, matter knotted itself into galaxies, galaxy clusters and filaments, weaving a dazzlingly intricate cosmic web. This web’s structure is thanks, in part, to the handiwork of neutrinos — lightweight, subatomic particles that surge through the cosmos in unimaginable numbers.

    Because they streak about at high speeds and rarely interact with other matter, the particles weren’t easily caught in the gravitational molasses of that latticework. So their presence swept away the cobwebs, hindering the formation of fine details in this cosmic filigree. More