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    Particles from space provide a new look inside cyclones

    Particles raining down from space offer 3-D views inside swirling tropical storms.

    Muons created from cosmic rays that smash into Earth’s upper atmosphere have revealed the inner workings of cyclones over Japan, researchers report October 6 in Scientific Reports. The new imaging approach could lead to a better understanding of storms, the researchers say, and offer another tool to help meteorologists forecast the weather.

    “Cosmic rays are sustainable natural resources that can be used everywhere on this planet for 24 hours [a day],” says geophysicist Hiroyuki Tanaka of the University of Tokyo, so it’s just a matter of taking advantage of them.

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    Muons offer a glimpse inside storms because variations in air pressure and density change the number of particles that make it through a tempest. By counting how many muons arrived at a detector on the ground in Kagoshima, Japan as cyclones moved past, Tanaka and colleagues produced rough 3-D maps of the density of air inside the storms. The approach gave the team an inside look at the low-pressure regions at the centers rotating storm systems.

    Muons, which are similar to electrons but roughly 200 times as massive, can scatter off molecules in the air. They’re also unstable, which means they break down into electrons and other particles called neutrinos given enough time. As air pressure increases, so does its density. That, in turn, increases the chances that a muon born from a cosmic ray will be bumped off its path on the way toward a detector or get slowed enough that it breaks down before it makes it all the way through the atmosphere.

    For every 1 percent increase in air pressure, Tanaka and colleagues say, the number of muons that survive passage from the upper atmosphere to the ground decreases by about 2 percent.

    Fewer muons make it through the high-pressure portions at the edges of a swirling cyclone (yellow and green in this muograph) than through the low-pressure regions in the center (red), providing a map of conditions inside the storm (illustrated outline). The darkened portion was outside the viewing angle of the muon detector.©2022 H.K.M. Tanaka

    Tanaka has previously used muons from cosmic rays to look inside volcanoes, and he suspects that others have used the particles to study weather (SN: 4/22/22). But, he says, this appears to be the first time that anyone has made 3-D muon scans of the insides of a storm.

    “It is an interesting approach,” says meteorologist Frank Marks of the National Oceanic and Atmospheric Administration’s Atlantic Oceanographic and Meteorological Laboratory in Miami, who wasn’t involved in the research.

    He doesn’t expect muon imaging to replace conventional meteorological measurements, but it’s another tool that scientists could use. “[It] would be complementary to our existing techniques to provide 3-D mapping of the storms with our other traditional observing systems, like satellites and radar.” More

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    Landslides shaped a hidden landscape within Yellowstone

    DENVER — A hidden landscape riddled with landslides is coming into focus in Yellowstone National Park, thanks to a laser-equipped airplane.

    Scientists of yore crisscrossed Yellowstone on foot and studied aerial photographs to better understand America’s first national park. But today researchers have a massive new digital dataset at their fingertips that’s shedding new light on this nearly 1-million-hectare natural wonderland.

    These observations of Yellowstone have allowed a pair of researchers to pinpoint over 1,000 landslides within and near the park, hundreds of which had not been mapped before, the duo reported October 9 at the Geological Society of America Connects 2022 meeting. Most of these landslides likely occurred thousands of years ago, but some are still moving.

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    Mapping Yellowstone’s landslides is important because they can cripple infrastructure like roadways and bridges. The millions of visitors that explore the park each year access Yellowstone through just a handful of entrance roads, one of which recently closed for months following intense flooding.

    In 2020, a small aircraft flew a few hundred meters above the otherworldly landscape of Yellowstone. But it wasn’t ferrying tourists eager for up close views of the park’s famous wolves or hydrothermal vents (SN: 7/21/20, SN: 1/11/21). Instead, the plane carried a downward-pointing laser that fired pulses of infrared light at the ground. By measuring the timing of pulses that hit the ground and reflected back toward the aircraft, researchers reconstructed the precise topography of the landscape.

    Such “light detection and ranging,” or lidar, data reveal details that often remain hidden to the eye. “We’re able to see the surface of the ground as if there’s no vegetation,” says Kyra Bornong, a geoscientist at Idaho State University in Pocatello. Similar lidar observations have been used to pinpoint pre-Columbian settlements deep within the Amazon jungle (SN: 5/25/22).

    The Yellowstone lidar data were collected as part of the 3D Elevation Program, an ongoing project spearheaded by the United States Geological Survey to map the entirety of the United States using lidar.

    Bornong and geomorphologist Ben Crosby analyzed the Yellowstone data — which resolve details as small as about one meter — to home in on landslides. The team searched for places where the landscape changed from looking relatively smooth to looking jumbled, evidence that soil and rocks had once been on the move. “It’s a pattern-recognition game,” says Crosby, also of Idaho State University. “You’re looking for this contrast between the lumpy stuff and the smooth stuff.”

    The researchers spotted more than 1,000 landslides across Yellowstone, most of which were clustered near the periphery of the park. That makes sense given the geography of Yellowstone’s interior, says Lyman Persico, a geomorphologist at Whitman College in Walla Walla, Wash., who was not involved in the research. The park sits atop a supervolcano, whose previous eruptions blanketed much of the park in lava (SN: 1/2/18). “You’re sitting in the middle of the Yellowstone caldera, where everything is flat,” says Persico.

    But steep terrain also abounds in the national park, and there’s infrastructure in many of those landslide-prone areas. In several places, the team found that roads had been built over landslide debris. One example is Highway 191, which skirts the western edge of Yellowstone.

    An aerial image of U.S. Highway 191 near Yellowstone shows barely perceptible signs of a long-ago landslide. But laser mapping reveals the structure and extent of the landslide in much greater detail (use the slider to compare images). It’s one of more than 1,000 landslides uncovered by new maps.

    It’s worth keeping an eye on this highway since it funnels significant amounts of traffic through regions apt to experience landslides, Bornong says. “It’s one of the busiest roads in Montana.”

    There’s plenty more to learn from this novel look at Yellowstone, Crosby says. Lidar data can shed light on geologic processes like volcanic and tectonic activity, both of which Yellowstone has in spades. “It’s a transformative tool,” he says. More

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    Jacky Austermann looks to the solid earth for clues to sea level rise

    It’s no revelation that sea levels are rising. Rising temperatures brought on by human-caused climate change are melting ice sheets and expanding ocean water. What’s happening inside Earth will also shape future shorelines. Jacky Austermann is trying to understand those inner dynamics.

    A geophysicist at Columbia University’s Lamont-Doherty Earth Observatory, Austermann didn’t always know she would end up studying climate. Her fascination with math from a young age coupled with her love of nature and the outdoors — she grew up hiking in the Alps — led her to study physics as an undergraduate, and later geophysics.

    As Austermann dug deeper into Earth’s geosystems, she learned just how much the movement of hot rock in the mantle influences life on the surface. “I got really interested in this entire interplay of the solid earth and the oceans and the climate,” she says.

    Big goal

    Much of Austermann’s work focuses on how that interplay influences changes in sea level. The global average sea level has risen more than 20 centimeters since 1880, and the yearly rise is increasing. But shifts in local sea level can vary, with those levels rising or falling along different shorelines, Austermann says, and the solid earth plays a role.

    “We think about sea level change generally as ‘ice is melting, so sea level is rising.’ But there’s a lot more nuance to it,” she says. “A lot of sea level change is driven by land motion.” 

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    Understanding that nuance could lead to more accurate climate models for predicting sea level rise in the future. Such work should help inform practical solutions for communities in at-risk coastal areas.

    So Austermann is building computer models that reconstruct sea level changes over the last few million years. Her models incorporate data on how the creeping churning of the mantle and other geologic phenomena have altered land and sea elevation, particularly during interglacial periods when Earth’s temperatures were a few degrees higher than they are today.

    Standout research

    Previous studies had suggested that this churning, known as mantle convection, sculpted Earth’s surface millions of years ago. “It pushes the surface up where hot material wells up,” Austermann says. “And it also drags [the surface] down where cold material sinks back into the mantle.”

    In 2015, Austermann and colleagues were the first to show that mantle-induced topographic changes influenced the melting of Antarctic ice over the last 3 million years. Near the ice sheet’s edges, ice retreated more quickly in areas where the land surface was lower due to convection.

    What’s more, mantle convection is affecting land surfaces even on relatively short time scales. Since the last interglacial period, around 130,000 to 115,000 years ago, mantle convection has warped ancient shorelines by as much as several meters, her team reported in Science Advances in 2017.  

    Jacky Austermann builds computer models that reconstruct sea level changes over the last few million years. The work could improve models that forecast the future.Bill Menke

    The growing and melting of ice sheets can deform the solid earth too, Austermann says. As land sinks under the weight of accumulating ice, local sea levels rise. And as land uplifts where the ice melts, water falls. This effect, as well as how the ice sheet tugs on the water around it, is shifting local sea levels around the globe today, she says, making it very relevant to coastal areas planning their defenses in the current climate crisis.

    Understanding these geologic processes can help improve models of past sea level rise. Austermann’s team is gathering more data from the field, scouring the coasts of Caribbean islands for clues to what areas were once near or below sea level. Such clues include fossilized corals and water ripples etched in stone, as well as tiny chutes in rocks that indicate air bubbles once rose through sand on ancient beaches. The work is “really fun,” Austermann says. “It’s essentially like a scavenger hunt.”

    Her efforts put the solid earth at the forefront of the study of sea level changes, says Douglas Wiens, a seismologist at Washington University in St. Louis. Before, “a lot of those factors were kind of ignored.” What’s most remarkable is her ability “to span what we normally consider to be several different disciplines and bring them together to solve the sea level problem,” he says.

    Building community

    Austermann says the most enjoyable part of her job is working with her students and postdocs. More than writing the next big paper, she wants to cultivate a happy, healthy and motivated research group. “It’s really rewarding to see them grow academically, scientifically, come up with their own ideas … and also help each other out.”

    Roger Creel, a Ph.D. student in Austermann’s group and the first to join her lab, treasures Austermann’s mentorship. She offers realistic, clear and fluid expectations, gives prompt and thoughtful feedback and meets for regular check-ins, he says. “Sometimes I think of it like water-skiing, and Jacky’s the boat.”

    For Oana Dumitru, a postdoc in the group, one aspect of that valued mentorship came in the form of a gentle push to write and submit a grant proposal on her own. “I thought I was not ready for it, but she was like, you’ve got to try,” Dumitru says.

    Austermann prioritizes her group’s well-being, which fosters collaboration, Creel and Dumitru say. That sense of inclusion, support and community “is the groundwork for having an environment where great ideas can blossom,” Austermann says.

    Want to nominate someone for the next SN 10 list? Send their name, affiliation and a few sentences about them and their work to sn10@sciencenews.org. More

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    The Tonga eruption may have spawned a tsunami as tall as the Statue of Liberty

    The massive Tonga eruption generated a set of planet-circling tsunamis that may have started out as a single mound of water roughly the height of the Statue of Liberty.

    What’s more, the explosive eruption triggered an immense atmospheric shock wave that spawned a second set of especially fast-moving tsunamis, a rare phenomenon that can complicate early warnings for these oft-destructive waves, researchers report in the October Ocean Engineering.

    As the Hunga Tonga–Hunga Ha’apai undersea volcano erupted in the South Pacific in January, it displaced a large volume of water upward, says Mohammad Heidarzadeh, a civil engineer at the University of Bath in England (SN: 1/21/22). The water in that colossal mound later “ran downhill,” as fluids tend to do, to generate the initial set of tsunamis.

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    To estimate the original size of the mound, Heidarzadeh and his team used computer simulations, as well as data from deep-ocean instruments and coastal tide gauges within about 1,500 kilometers of the eruption, many of them in or near New Zealand. The arrival times of tsunami waves, as well as their sizes, at those locations were key pieces of data, Heidarzadeh says.

    The team analyzed nine possibilities for the initial wave, each of which was shaped like a baseball pitcher’s mound and had a distinct height and diameter. The best fit to the real-world data came from a mound of water a whopping 90 meters tall and 12 kilometers in diameter, the researchers report.

    That initial wave would have contained an estimated 6.6 cubic kilometers of water. “This was a really large tsunami,” Heidarzadeh says.

    Despite starting out about nine times as tall as the tsunami that devastated the Tohoku region of Japan in 2011, the Tongan tsunamis killed only five people and caused about $90 million in damage, largely because of their remote source (SN: 2/10/12).

    Another unusual aspect of the Tongan eruption is the second set of tsunamis generated by a strong atmospheric pressure wave.

    That pressure pulse resulted from a steam explosion that occurred when a large volume of seawater infiltrated the hot magma chamber beneath the erupting volcano. As the pressure wave raced across the ocean’s surface at speeds exceeding 300 meters per second, it pushed water ahead of it, creating tsunamis, Heidarzadeh explains.

    The eruption of the Hunga Tonga-Hunga Ha’apai volcano also triggered an atmospheric pressure wave that in turn generated tsunamis that traveled quicker than expected.NASA Earth Observatory

    Along many coastlines, including some in the Indian Ocean and Mediterranean Sea, these pressure wave–generated tsunamis arrived hours ahead of the gravity-driven waves spreading from the 90-meter-tall mound of water. Gravity-driven tsunami waves typically travel across the deepest parts of the ocean, far from continents, at speeds between 100 and 220 meters per second. When the waves reach shallow waters near shore, the waves slow, water stacks up and then strikes shore, where destruction occurs.

    Pressure wave–generated tsunamis have been reported for only one other volcanic eruption: the 1883 eruption of Krakatau in Indonesia (SN: 8/27/83).

    Those quicker-than-expected arrival times — plus the fact that the pressure-wave tsunamis for the Tongan eruption were comparable in size with the gravity-driven ones — could complicate early warnings for these tsunamis. That’s concerning, Heiderzadeh says.

    One way to address the issue would be to install instruments that measure atmospheric pressure with the deep-sea equipment already in place to detect tsunamis, says Hermann Fritz, a tsunami scientist at Georgia Tech in Atlanta.

    With that setup, scientists would be able to discern if a passing tsunami is associated with a pressure pulse, thus providing a clue in real time about how fast the tsunami wave might be traveling. More

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    The Arctic is warming even faster than scientists realized

    The Arctic is heating up at a breakneck speed compared with the rest of Earth. And new analyses show that the region is warming even faster than scientists thought. Over the last four decades, the average Arctic temperature increased nearly four times as fast as the global average, researchers report August 11 in Communications Earth & Environment.

    And that’s just on average. Some parts of the Arctic Ocean, such as the Barents Sea between Russia and Norway’s Svalbard archipelago, are warming as much as seven times as fast, meteorologist Mika Rantanen of the Finnish Meteorological Institute in Helsinki and colleagues found. Previous studies have tended to say that the Arctic’s average temperature is increasing two to three times as fast as elsewhere, as humans continue causing the climate to change.

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    To calculate the true pace of the accelerated warming, a phenomenon called Arctic amplification, the researchers averaged four sets of satellite data from 1979 to 2021 (SN: 7/1/20). Globally, the average temperature increase over that time was about 0.2 degrees Celsius per decade. But the Arctic was warming by about 0.75 degrees C per decade.

    Even the best climate models are not doing a great job of reproducing that warming, Rantanen and colleagues say. The inability of the models to realistically simulate past Arctic amplification calls into question how well the models can project future changes there.

    It’s not clear where the problem lies. One issue may be that the models are struggling with correctly simulating the sensitivity of Arctic temperatures to the loss of sea ice. Vanishing snow and ice, particularly sea ice, are one big reason why Arctic warming is on hyperspeed. The bright white snow and ice create a reflective shield that bounces incoming radiation from the sun back into space. But open ocean waters or bare rocks absorb that heat, raising the temperature. More

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    50 years ago, a new theory of Earth’s core began solidifying

    How the Earth got its core – Science News, July 1, 1972

    In the beginning, scientists believe there was an interstellar gas cloud of all the elements comprising the Earth. A billion or so years later, the Earth was a globe of concentric spheres with a solid iron inner core, a liquid iron outer core and a liquid silicate mantle…. The current theory is that the primeval cloud’s materials accreted … and that sometime after accretion, the iron, melted by radioactive heating, sank toward the center of the globe…. Now another concept is gaining ground: that the Earth may have accreted … with core formation and accretion occurring simultaneously.

    Update

    Most scientists now agree that the core formed as materials that make up Earth collided and glommed together and that the process was driven by heat from the smashups. The planet’s heart is primarily made of iron, nickel and some oxygen, but what other elements may dwell there and in what forms remains an open question. Recently, scientists proposed the inner core could be superionic, with liquid hydrogen flowing through an iron and silicon lattice (SN: 3/12/22, p. 12). More

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    Scientists are racing to save the Last Ice Area, an Arctic Noah’s Ark

    It started with polar bears.

    In 2012, polar bear DNA revealed that the iconic species had faced extinction before, likely during a warm period 130,000 years ago, but had rebounded. For researchers, the discovery led to one burning question: Could polar bears make a comeback again?

    Studies like this one have emboldened an ambitious plan to create a refuge where Arctic, ice-dependent species, from polar bears down to microbes, could hunker down and wait out climate change. For this, conservationists are pinning their hopes on a region in the Arctic dubbed the Last Ice Area — where ice that persists all summer long will survive the longest in a warming world.

    Here, the Arctic will take its last stand. But how long the Last Ice Area will hold on to its summer sea ice remains unclear. A computer simulation released in September predicts that the Last Ice Area could retain its summer sea ice indefinitely if emissions from fossil fuels don’t warm the planet more than 2 degrees Celsius above preindustrial levels, which is the goal set by the 2015 Paris Climate Agreement (SN: 12/12/15). But a recent report by the United Nations found that the climate is set to warm 2.7 degrees Celsius by 2100 under current pledges to reduce emissions, spelling the end of the Arctic’s summer sea ice (SN: 10/26/21).

    Nevertheless, some scientists are hoping that humankind will rally to curb emissions and implement technology to capture carbon and other greenhouse gases, which could reduce, or even reverse, the effects of climate change on sea ice. In the meantime, the Last Ice Area could buy ice-dependent species time in the race against extinction, acting as a sanctuary where they can survive climate change, and maybe one day, make their comeback.

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    Ecosystem of the frozen sea

    The Last Ice Area is a vast floating landscape of solid ice extending from the northern coast of Greenland to Canada’s Banks Island in the west. This region, roughly the length of the West Coast of the United States, is home to the oldest and thickest ice in the Arctic, thanks to an archipelago of islands in Canada’s far north that prevents sea ice from drifting south and melting in the Atlantic.

    As sea ice from others part of the Arctic rams into this natural barrier, it piles up, forming long towering ice ridges that run for kilometers across the frozen landscape. From above, the area appears desolate. “It’s a pretty quiet place,” says Robert Newton, an oceanographer at Columbia University and coauthor of the recent sea ice model, published September 2 in Science. “A lot of the life is on the bottom of the ice.”

    The muddy underbelly of icebergs is home to plankton and single-celled algae that evolved to grow directly on ice. These species form the backbone of an ecosystem that feeds everything from tiny crustaceans all the way up to beluga whales, ringed seals and polar bears.

    These plankton and algae species can’t survive without ice. So as summer sea ice disappears across the Arctic, the foundation of this ecosystem is literally melting away. “Much of the habitat Arctic species depend on will become uninhabitable,” says Brandon Laforest, an Arctic expert at World Wildlife Fund Canada in Montreal. “There is nowhere else for these species to go. They’re literally being squeezed into the Last Ice Area.”

    The Last Ice Area extends across national borders, making it especially challenging to protect the last summer sea ice in the Arctic. The extent of the ice is predicted to shrink considerably by 2039.WWF CanadaThe Last Ice Area extends across national borders, making it especially challenging to protect the last summer sea ice in the Arctic. The extent of the ice is predicted to shrink considerably by 2039.WWF Canada

    The last stronghold of summer ice provides an opportunity to create a floating sanctuary —an Arctic ark if you will — for the polar bears and many other species that depend on summer ice to survive. For over a decade, WWF Canada and a coalition of researchers and Indigenous communities have lobbied for the area to be protected from another threat: development by industries that may be interested in the region’s oil and mineral resources.

    “The tragedy would be if we had an area where these animals could survive this bottleneck, but they don’t because it’s been developed commercially,” Newton says.

    But for Laforest, protecting the Last Ice Area is not only a question of safeguarding arctic creatures. Sea ice is also an important tool in climate regulation, as the white surface reflects sunlight back into space, helping to cool the planet. In a vicious cycle, losing sea ice helps speed up warming, which in turn melts more ice.

    And for the people who call the Arctic home, sea ice is crucial for food security, transportation and cultural survival, wrote Inuit Circumpolar Council Chair Okalik Eegeesiak in a 2017 article for the United Nations. “Our entire cultures and identity are based on free movement on land, sea ice and the Arctic Ocean,” Eegeesiak wrote. “Our highway is sea ice.” 

    The efforts of these groups have borne some fruit. In 2019, the Canadian government moved to set aside nearly a third of the Last Ice Area as protected spaces called marine preserves. Until 2024, all commercial activity within the boundaries of the preserves is forbidden, with provisions for Indigenous peoples. Conservationists are now asking these marine preserves to be put under permanent protection.

    Rifts in the ice

    However, there are some troubling signs that the sea ice in the region is already precarious. Most worrisome was the appearance in May 2020 of a Rhode Island—sized rift in the ice at the heart of the Last Ice Area. Kent Moore, a geophysicist at the University of Toronto, says that these unusual events may become more frequent as the ice thins. This suggests that the Last Ice Area may not be as resilient as we thought, he says.  

    This is something that worries Laforest. He and others are skeptical that reversing climate change and repopulating the Arctic with ice-dependent species will be possible. “I would love to live in a world where we eventually reverse warming and promote sea ice regeneration,” he says. “But stabilization seems like a daunting task on its own.”

    Still, hope remains. “All the models show that if you were to bring temperatures back down, sea ice will revert to its historical pattern within several years,” says Newton.

    To save the last sea ice — and the creatures that depend on it — removing greenhouse gases from the atmosphere will be essential, says oceanographer Stephanie Pfirman of Arizona State University in Tempe, who coauthored the study on sea ice with Newton. Technology to capture carbon, and prevent more carbon from entering the atmosphere, already exists. The largest carbon capture plant is in Iceland, but projects like that one have yet to be implemented on a major scale.

    Without such intervention, the Arctic is set to lose the last of its summer ice before the end of the century. It would mean the end of life on the ice. But Pfirman, who suggested making the Last Ice Area a World Heritage Site in 2008, says that humankind has undergone big economic and social changes — like the kind needed to reduce emissions and prevent warming — in the past. “I was in Germany when the [Berlin] wall came down, and people hadn’t expected that to happen,” she says.

    Protecting the Last Ice Area is about buying time to protect sea ice and species, says Pfirman. The longer we can hold on to summer sea ice, she says, the better chance we have at bringing arctic species —from plankton to polar bears — back from the brink.    More

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    Earth’s lower atmosphere is rising due to climate change

    Global temperatures are rising and so, it seems, is part of the sky.

    Atmosphere readings collected by weather balloons in the Northern Hemisphere over the last 40 years reveal that climate change is pushing the upper boundary of the troposphere — the slice of sky closest to the ground — steadily upward at a rate of 50 to 60 meters per decade, researchers report November 5 in Science Advances.

    Temperature is the driving force behind this change, says Jane Liu, an environmental scientist at the University of Toronto. The troposphere varies in height around the world, reaching as high as 20 kilometers in the tropics and as low as seven kilometers near the poles. During the year, the upper boundary of the troposphere — called the tropopause — naturally rises and falls with the seasons as air expands in the heat and contracts in the cold. But as greenhouse gases trap more and more heat in the atmosphere, the troposphere is expanding higher into the atmosphere (SN: 10/26/21).

    Liu and her colleagues found that the tropopause rose an average of about 200 meters in height from 1980 to 2020. Nearly all weather occurs in the troposphere, but it’s unlikely that this shift will have on a big effect on weather, the researchers say. Still, this research is an important reminder of the impact of climate change on our world, Liu says.

    “We see signs of global warming around us, in retreating glaciers and rising sea levels,” she says. “Now, we see it in the height of the troposphere.” More