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Journey Into the Fiery Depths of Earth’s Youngest Caves

What Iceland's volcanoes are revealing about early life on our planet

Francesco Sauro first explored a cave when he was 4 years old. He was with his dad, a professor of geography, in the Lessini mountains, near the northern Italian village of Bosco Chiesanuova, where his father had grown up. His dad was also an amateur cave explorer, and the trip was a kind of preordained rite of passage. “The only memory I have about those caves is that I cried,” Sauro recalls. “I was very scared because of the darkness.” When Sauro was 12, and visiting the area again with his family, the founder of a local museum told him that a nearby cave held the bones of ancient cave birds. “In that moment, my curiosity overcame my fear,” Sauro says. From that day on, he was hooked. Adrien Briod, of the Swiss drone company Flyability, operates a drone equipped with a lidar scanner to minutely map a network of lava tubes in 3D. Robbie Shone In the nearly three decades since, the 39-year-old geologist has trekked into dozens of caves around the world: on islands in the Atlantic Ocean, inside glacier mills in the Alps, beneath the forest floor of the Amazon rainforest. In 2013, he discovered some of the world’s oldest caves inside the mountain known as Auyán Tepui in Venezuela. All told, he’s surveyed more than 60 miles of these hidden worlds, including several caves that were unknown to humankind. Some were millions of years old. Others formed tens of thousands of years ago. Recently, he explored caves that are even younger: pristine cavities known as lava tubes, forged inside cooling mounds of molten rock during the eruption of the Fagradalsfjall volcano, in southern Iceland, in 2021. For explorers looking to set foot on uncharted territory, few spaces can match the novelty. But beyond that elemental thrill, these infant caves offer an exceedingly rare opportunity to study cavernous worlds almost from their moment of origin. This article is a selection from the June 2024 issue of Smithsonian magazine The researchers cross a lava field on the Reykjanes Peninsula to investigate a cave entrance in May 2023, during the second expedition to the site. Robbie Shone The most common caves on Earth are formed when rainwater mixes with carbon dioxide in the soil and turns into a weak acid, dissolving soft, soluble rock such as limestone below. Similar “destructional” caves are formed inside mountains and rocky formations made of less soluble material such as basalt, when flowing water slowly erodes the stone over long periods of time. “Constructional” caves, by contrast, are forged when flowing lava begins to cool, creating a top, crusty layer that solidifies into rock. As the molten lava beneath the crust flows out, it leaves behind a new cavity—a lava tube. “These caves are built in an instant of geologic time,” Sauro says. Lava tubes can range in size from a small hollow barely three feet in diameter to a large chamber more than 150 feet tall. They can be formed as a single conduit, or as a series of small, interconnected tubes. Some might be “tiered” one on top of another—a stack of caves. In a tent beside the volcano, Martina Cappelletti, far left, and Ana Miller, both microbiologists, with expedition leader Francesco Sauro. The researchers are examining high-resolution scans of bacteria collected from inside a cave. Robbie Shone Somewhere between 50 to 70 of the planet’s 1,500 or so active volcanoes erupt every year. When Mount Fagradalsfjall began to erupt in March 2021, capping what had been more than 800 years of dormancy, the world looked on with fascination, in part because an eruption elsewhere in Iceland a decade earlier spewed giant clouds of ash into the atmosphere over Europe, impacting air travel. This time there was no such disruption. Instead, tourists from Iceland and around the world swarmed to the site, some getting within 500 or so feet of the eruption, to glimpse the brilliant red and crimson lava gushing from the mountain and cascading down its sides. “It was the first case where we had cameras everywhere around the volcano, and images coming from the thousands of tourists that were going there to see this incredible show,” Sauro says. Mineral deposits after exposure to weather and UV light. Because some “metastable” minerals may change over time, researchers strove to retrieve samples quickly. Robbie Shone Sauro, a full-time speleologist and president of a geographical exploration society called La Venta who also works with NASA and the European Space Agency to help train astronauts in planetary exploration, monitored these developments from his home in northern Italy. He spent hours each day looking at photographs and video footage from the site. This rich stream of information was not just giving researchers the ability to track how and where the caves were forming. It also presented a rare chance to study the interiors of caves that hadn’t yet been touched by living matter: to observe the cooling process, the formation of minerals and the early microbial colonization of those environments in unprecedented detail. And because the caves were formed from lava surpassing temperatures of 1,800 degrees Fahrenheit, the environment inside would be completely sterile. “I was thinking: Hey, as soon as the eruption stops, this will become like an incredible laboratory,” Sauro recalls. “This will become a new world.” Mount Fagradalsfjall is not actually a single mountain but a cluster of small ridges on a plateau on the Reykjanes Peninsula, about 25 miles southwest of Reykjavik. The surrounding area is flat and covered in moss. The eruption began in a valley between the ridges. As it continued over the next few months, Sauro began making plans. He knew it was imperative to access the caves as soon as physically possible. Miller collects a mineral sample from a cave filled with toxic gases. Among the rare minerals found so far is wulffite, recorded only once before, near a Russian volcano. Robbie Shone That time was of the essence was a lesson that speleologists had learned in 1994, when studying lava tubes formed after Mount Etna erupted in Italy. When they entered the tubes nearly a year after the eruption had stopped, at which point the temperature inside was still a dangerously high 158 degrees, the researchers found rare crystals and minerals. Returning six months later, however, those minerals were gone. They were “metastable”—holding their form only at high temperatures. As the lava tubes cooled, they had disappeared, and so had the opportunity to examine them in detail. To prepare to enter the new caves in Iceland, Sauro and his team needed a precise understanding of where exactly they were forming and which tubes presented the easiest and safest access. Gro Pedersen, a geologist at the University of Iceland’s Nordic Volcanological Center, was tasked with collecting images. She and Birgir Óskarsson, from the Icelandic Institute of Natural History, surveyed the volcano from an airplane, flying over it once every two weeks or so between March and September 2021. They also collected other images captured by drones and satellite imagery. “Because of the different angles, we were actually able to create a topographic map, in addition to a good visual map of the lava flow field,” Pedersen says. Bogdan Onac, a mineralogist, uses a thermal imaging camera to map temperatures inside the cave. One cave wall, still glowing, was recorded at nearly 1,100 degrees Fahrenheit. Robbie Shone Sauro and his colleagues, who had received a grant from the National Geographic Society, finally got close to the volcano in September 2021, about a week after the eruption subsided. Using their maps, the team identified windows, or “skylight points,” on the surface—locations that were potential entrances into newly formed caves. They flew a drone equipped with thermal imaging cameras over the site to map the temperatures of different parts of the volcanic landscape. In May 2022, they were able to approach the entrances of several caves, but thermal cameras indicated that inside temperatures were still reaching 900 degrees. “There was burning air coming out,” Sauro says. “The winds outside were cold. The contrast between the exterior and the interior was crazy.” Giovanni Rossi, center, and Tommaso Santagata through a 1,000-foot-long lava tube—among the youngest caves on Earth. Robbie Shone Sauro and his expedition members finally entered one of the caves that October, wearing metallurgist suits designed to withstand high temperatures and breathing from portable tanks filled with compressed air, because the air inside was too hot to breathe and laden with toxic gases. The walls were still radiating heat like a furnace, and in certain places the floor was nearly 400 degrees. Sauro and two other team members, equipped with thermal imaging cameras to monitor conditions, advanced cautiously, like a line of soldiers, allowing for the person in the middle and the person in the rear to pull back the line leader in case the expedition suddenly turned dangerous. “The air temperature could change from 100 to 200 degrees [Celsius] in just one meter,” Sauro says. In one tube Sauro entered, the cave wall was still glowing, with a temperature of nearly 600 degrees Celsius (1,100 degrees Fahrenheit). “It was one of the most impressive things I saw,” he says. Pedersen visited the caves after they had cooled further. “I know very few places on Earth where you can go into things that you have seen being born,” she says. “That’s kind of amazing.” Two lines of research interested Sauro and his colleagues. First, they were eager to study the minerals they would find inside the caves—those formed on the cave walls and other rocky surfaces. Second, they hoped to discover when these extreme habitats would be colonized by micro-organisms and discern which microbes would thrive. Learning how such newly formed caves might begin to harbor life could help researchers refine their ideas about how life developed on Earth, and it would also provide guidance about how and where to look for signs of life, current or past, on other planets, such as Mars. “We know that lava tubes were constantly forming in Martian volcanoes,” Sauro explains. “So they could have been quickly colonized, becoming a kind of Noah’s Ark for Martian life—if life ever existed there.” Mineral encrustations offer clues about which microbes first colonize caves—usually those, researchers found, that can derive energy from oxidizing inorganic materials such as sulfur, iron and copper. Robbie Shone Concerned that some minerals could change or disappear over time, the researchers brought a scanning electron microscope to the site to produce high-resolution images of the samples to help them identify them. Rogier Miltenburg, a technician with the biotechnology company Thermo Fisher Scientific, housed the instrument inside a tent next to the volcano, and he ran a generator inside the tent to maintain the vacuum needed for the microscope to function. The conditions were precarious: Once, when it was raining, a river started to form through the tent. “I had the power supply on the floor, and luckily the water sort of diverted around it,” Miltenburg recalls. “Otherwise we would have had a short.” Mineral encrustations offer clues about which microbes first colonize caves—usually those, researchers found, that can derive energy from oxidizing inorganic materials such as sulfur, iron and copper. Robbie Shone The researchers came across a variety of minerals along fissures and grooves on the cave surfaces. “We found this beautiful white stuff. And then we said, ‘Wait a minute, that’s green there, that’s blue there,’” says Bogdan Onac, a mineralogist at the University of South Florida who was part of the team. Using sterile spatulas, the researchers scraped off samples and packed them in vacuum-sealed bags. Since the temperatures in the lava tubes were so high at the outset, Onac was expecting the minerals to be completely dehydrated crystals, so he was surprised to find some whose texture resembled that of wet sugar, indicating that, in spite of the high heat, water molecules in the environment had been incorporated during mineralization. After collecting samples, Sauro and his colleagues would turn around and walk to the tent for a look at what they had found. By ascertaining a sample’s chemical composition from the images produced by the electron microscope, they could usually identify the mineral within half an hour. Rare forms of minerals—including sodium, potassium and copper—grow along a fracture in the walls of a 122 degree Fahrenheit lava tube on the Fagradalsfjall lava field. Robbie Shone The team had expected to find some minerals such as mirabilite, which is made up of hydrogen, sodium and sulfur. But they also found novel minerals formed from the combination of copper with sodium, potassium, sulfur and other elements, resulting in rare substances that the team is currently studying in greater detail. One surprise mineral, for instance, was wulffite—an emerald-green crystal whose composition includes sodium and potassium along with copper sulfate. “It has only been found once before in the history of mineralogy, in a Russian volcano site,” says Fabrizio Nestola, a mineralogist at the University of Padua. Nestola, who is conducting detailed analyses of the mineral samples at his Padua lab, is certain that some of the minerals will turn out to be entirely new to science, potentially revealing as yet unknown processes by which mineralization takes place. Samples prepared for the on-site scanning electron microscope. The instrument, housed in a tent, required a generator to maintain the vacuum it uses to function. Robbie Shone Sauro’s microbiologist colleagues, meanwhile, collected samples from patches of rock surfaces marked by “biofilms”—areas that had begun to be colonized by bacteria. After extracting samples and analyzing DNA from them at laboratories off-site, the researchers found that different micro-organisms had flourished in different parts of the same cave. “The first data indicate that environmental bacteria, mostly those associated with soil, begin the colonization,” says Martina Cappelletti of the University of Bologna, a microbiologist. “They are probably initially transported inside the cave through air currents.” These micro-organisms can thrive because they are able to subsist on rocks—that is, to derive energy from oxidizing inorganic materials. Over time, as the caves cooled, the diversity of microbes inside the caves increased. The findings suggest that such life-forms, which would not require water or organic matter to survive, should have the best chance to establish a foothold in extreme environments—whether in the distant past or on other planets. Onac inside the microscope tent. Already the researchers have found several rare minerals, he said. And not only that. “Some of them will be new to science.” Robbie Shone Indeed, tracking microbial colonization will help scientists searching for life elsewhere in the universe. Even on planets where surface conditions today seem inhospitable, lava tubes may once have provided temporary or enduring refuge to life-forms that rapidly colonized the interiors and survived. “If some specific microbial life is able to quickly colonize lava tubes on Earth, why could this not have happened on Mars?” Sauro says. The view from inside a lava tube whose walls have collapsed. “If you’re there while there are earthquakes—that’s not good,” Sauro deadpanned. Robbie Shone Penelope Boston, director of NASA’s Astrobiology Institute at NASA Ames, Moffett Field, describes lava tubes as “a model for what we may potentially find on other bodies in the solar system.” And volcanic activity isn’t limited to Earth and Mars. Even Io, one of Jupiter’s moons, has active volcanoes, suggesting that planets and moons beyond our solar system may have volcanoes—and lava tubes—too. That’s why Boston sees great value in studying the caves Sauro is investigating. “I think that designating places around the world where we have this ability to see an early history of microbial colonization from the get-go is something that deserves worldwide attention,” she says. A small lava lake inside a cave, now solidified. Robbie Shone A swirly segment of a surface lava field, near the volcano crater. Robbie Shone A wall detail near a cave entrance. Robbie Shone The eruption of Fagradalsfjall has subsided, but Sauro has been following news about other volcanoes in Iceland with interest. This past March, when a new eruption started on the Reykjanes Peninsula, at Mount Hagafell, a few miles west of Fagradalsfjall, he mused about “new tubes forming, literally, right now.” These uncharted caverns could be his next hunting ground. 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Going with the Flow: Exploring Hogtown Creek Headwaters Nature Park

The streams near the trail pass through wetlands, which play a vital role in filtering out pollution from the water. Despite the sanitary start, the creek collects pollutants as it leaves the wetlands and flows further into the city. Runoff carrying chemicals, animal waste, and even trash seep into the creek as it travels, and these pollutants eventually end up in the aquifer, which Gainesville relies on for its drinking water.

Companies Legally Use Poison to Make Your Decaf Coffee

Do you drink decaffeinated coffee? Are you aware that it’s often made by applying a chemical so dangerous it was banned for use in paint stripper five years ago? And are you aware that companies think banning this chemical is really, really unfair?This week the Environmental Protection Agency finalized a rule prohibiting all but “critical” uses of methylene chloride, a highly toxic liquid that is believed to have killed at least 88 people since 1980—mostly workers refinishing bathtubs or doing other home renovations. Methylene chloride can cause liver damage and is linked to multiple cancers, among other health effects. Amazingly, while the EPA banned its sale for paint stripping in 2019 for this reason, it continues to be used for a lot of other purposes. And one of those is decaffeinating coffee, because the Food and Drug Administration decided in the 1980s that the risk to coffee drinkers was low given how the coffee was processed.The EPA’s ban on noncritical use of methylene chloride is one of many rules the Biden administration has announced or finalized ahead of the Congressional Review Act deadline. (The CRA, essentially, makes it easier for an unfriendly Congress to nix any administrative regulations finalized in the last 60 days of a legislative session.) A lot of the recently announced rules ban or curtail toxic substances that have made their way into everyday life and are poisoning people. The EPA has limited long-lasting chemicals called PFAS in drinking water, requiring water utilities within five years to build treatment systems that remove it. The agency has categorized two types of PFAS as hazardous substances under the Superfund law, requiring manufacturers to monitor whether they’ve been released into the environment and, if so, clean them up. It has also—finally—fully banned asbestos. It’s finalized a rule to further restrict fine particulate pollution in the air, which has been linked to heart disease, heart attacks, asthma, low birth weight, Alzheimer’s, and other forms of dementia. It’s in the process of finalizing a rule reducing lead in drinking water, which would require the replacement of lead pipes throughout the nation.Banning poison is good politics. As mentioned in last week’s newsletter, while only 47 percent of respondents in a recent CBS News poll supported reentering the Paris climate agreement, 70 percent said they supported reducing toxic chemicals in drinking water. That’s consistent with other polls showing that a majority of people think the federal government is doing too little to protect “lakes, rivers and streams,” and that an overwhelming majority of people—even 68 percent of Republicans—believe the federal government should play some role in “addressing differences across communities in their health risks from pollution and other environmental problems.”But every single time one of these rules is announced, companies and industry groups respond with the most ridiculous statements. Let’s look at just a few recent examples.“A group of coffee makers against banning methylene chloride,” Boston radio station WBUR reported in early April, “recently wrote the FDA saying, ‘True coffee aficionados in blind tastings’ prefer coffee decaffeinated with the chemical.” Who knows how this study was done—“True coffee aficionados” are not known for preferring decaf, period, hence a recent P.R. push to improve decaf’s image. Nick Florko, a reporter for health news website Stat, told WBUR that the coffee makers’ letter to the FDA was a “pretty funny claim if you consider the fact that we’re talking about coffee here that’s essentially rinsed in paint thinner.” And this says nothing at all about what happens to workers involved in the decaffeination process. (Methylene chloride has previously been shown to poison even trained workers wearing protective gear.)National Coffee Association president William Murray said something even weirder, telling CNN via email that banning methylene chloride “would defy science and harm American[s’] health.” His logic appeared to be that since all coffee consumption, including decaf, shows signs of reducing cancer risk overall, it’s not really a problem to decaffeinate coffee using a known carcinogen. That’s loopy even for industry pushback. For one thing, it’s easy to imagine that coffee could be good in general, and less good if you add poison to it. For another, coffee can also be decaffeinated without methylene chloride, using only water. Now let’s look at PFAS pushback. Knowing the EPA rules were in progress, the U.S. Chamber of Commerce in March launched the “Essential Chemistry for America” initiative, with the goal of “protecting ‘forever chemicals’ it deems ‘critical,’” according to E&E News. “We’re increasingly concerned that overly broad regulatory approaches threaten access to modern fluorochemistries, so we’re taking action to ensure their availability,” chamber vice president Marty Durbin said. Given that “access” language is typically used in a social and environmental justice context, restyling the regulation of poisons as threatening “access to modern fluorochemistries” is gutsy, to say the least. The private water industry is meanwhile throwing a fit about being asked to filter out PFAS. The rule will “throw public confidence in drinking water into chaos,” Mike McGill, president of water industry communications firm WaterPIO, told the AP. (You’d think the existence of PFAS in the water is what would tank public confidence, not the requirement that it be removed.) Then there’s the common threat from private water utilities—which, remember, turn a profit off providing a substance people can’t live without—that removing PFAS will increase people’s water bills. Robert Powelson, the head of the National Association of Water Companies, said that the costs of the federal regulation “will disproportionately fall on water and wastewater customers,” according to The Washington Post. “Water utilities do not create or produce PFAS chemicals,” Powelson added. “Yet water systems and their customers are on the front lines of paying for the cleanup of this contamination.”It’s true enough that water utilities are not the ones creating PFAS chemicals. On the other hand, there are lots of water contaminants that water utilities are responsible for filtering out if they want to keep making money from providing people with drinking water. Is there really any reason PFAS shouldn’t be among them? Saying that the cost of this regulation “will disproportionately fall on water and wastewater customers” shouldn’t be read as an expression of sympathy for disadvantaged households. The burden will fall on customers because the utilities will make sure of it. It’s a threat, and one that doesn’t mention the federal money from the Inflation Reduction Act that is being made available to help shoulder that burden. Those funds may well fall short, but that doesn’t change the fact that they’re paying for-profit entities to transition to removing something they ought to have been filtering out long ago. And even if this federal rule hadn’t been made, companies would probably have to start removing PFAS anyway, because they are facing increasingly expensive lawsuits over not doing so. (The water utilities, in turn, are suing polluters to cover remediation costs—another source of funding.)It’s worth emphasizing what PFAS chemicals actually do to people, particularly in light of the American Water Works Association’s assertion to the AP that the cost of removing the chemicals “can’t be justified for communities with low levels of PFAS.” Researchers are now pretty sure that PFAS exposure increases the risk of dying from cardiovascular disease. Studying people in northern Italy who drank PFAS-contaminated water, researchers also saw increased rates of kidney and testicular cancer. The Guardian report on this contained this disturbing finding too: Women with multiple children had lower levels of PFAS only because pregnancy transferred PFAS into their children’s bodies instead.Don’t let that get in the way of a good comms statement from industry groups, though. Remember: Forcing companies even to report their PFAS pollution, or remove PFAS from the water, is unfair.Good News/Bad NewsTwenty-nine-year-old Andrea Vidaurre has won the Goldman Environmental Prize for her work in environmental justice, pushing California to adopt new standards for truck and rail emissions that will curtail the air pollution harming working-class Latino communities in California’s Inland Empire. The United States has sided with petrostates in opposing production controls on plastic at the negotiations in Ottawa for a U.N. treaty to reduce plastic pollution. (Two weeks ago, I wrote about these negotiations, noting that the number of plastics industry lobbyists attending this session was not yet known. Now it is: 196 lobbyists from the fossil fuel and chemical industries registered for this round, according to the Center for International Environmental Law—a 37 percent increase from the number at the last session.)Stat of the Week9.6%That’s the percentage of the 250 most popular fictional films released between 2013 and 2022 in which climate change exists and a character depicted on screen knows it, according to a new “Climate Reality Check” analysis from Colby University and Good Energy. Read Sammy Roth’s newsletter about why climate change in movies is so important here.What I’m ReadingBig Oil privately acknowledged efforts to downplay climate crisis, joint committee investigation findsCongressional Democrats this week released a report confirming what news outlets have previously reported: Companies like Exxon knew about climate change very early on and covered it up. They also found in subpoenaed emails that Exxon tried to discredit reporting of its duplicity, while privately acknowledging that it was true:The new revelations build on 2015 reporting from Inside Climate News and the Los Angeles Times, which found that Exxon was for decades aware of the dangers of the climate crisis, yet hid that from the public.At the time, Exxon publicly rejected the journalists’ findings outright, calling them “inaccurate and deliberately misleading.” … But in internal communications, Exxon confirmed the validity of the reporting. In a December 2015 email about a potential public response to the investigative reporting, Exxon communications advisor Pamela Kevelson admitted the company did not “dispute much of what these stories report.” … “It’s true that Inside Climate News originally accused us of working against science but ultimately modified their accusation to working against policies meant to stop climate change,” Alan Jeffers, then a spokesperson for Exxon, wrote in a 2016 email to Kevelson. “I’m OK either way, since they were both true at one time or another.”Read Dharna Noor’s report in The Guardian.This article first appeared in Life in a Warming World, a weekly TNR newsletter authored by deputy editor Heather Souvaine Horn. Sign up here.

Do you drink decaffeinated coffee? Are you aware that it’s often made by applying a chemical so dangerous it was banned for use in paint stripper five years ago? And are you aware that companies think banning this chemical is really, really unfair?This week the Environmental Protection Agency finalized a rule prohibiting all but “critical” uses of methylene chloride, a highly toxic liquid that is believed to have killed at least 88 people since 1980—mostly workers refinishing bathtubs or doing other home renovations. Methylene chloride can cause liver damage and is linked to multiple cancers, among other health effects. Amazingly, while the EPA banned its sale for paint stripping in 2019 for this reason, it continues to be used for a lot of other purposes. And one of those is decaffeinating coffee, because the Food and Drug Administration decided in the 1980s that the risk to coffee drinkers was low given how the coffee was processed.The EPA’s ban on noncritical use of methylene chloride is one of many rules the Biden administration has announced or finalized ahead of the Congressional Review Act deadline. (The CRA, essentially, makes it easier for an unfriendly Congress to nix any administrative regulations finalized in the last 60 days of a legislative session.) A lot of the recently announced rules ban or curtail toxic substances that have made their way into everyday life and are poisoning people. The EPA has limited long-lasting chemicals called PFAS in drinking water, requiring water utilities within five years to build treatment systems that remove it. The agency has categorized two types of PFAS as hazardous substances under the Superfund law, requiring manufacturers to monitor whether they’ve been released into the environment and, if so, clean them up. It has also—finally—fully banned asbestos. It’s finalized a rule to further restrict fine particulate pollution in the air, which has been linked to heart disease, heart attacks, asthma, low birth weight, Alzheimer’s, and other forms of dementia. It’s in the process of finalizing a rule reducing lead in drinking water, which would require the replacement of lead pipes throughout the nation.Banning poison is good politics. As mentioned in last week’s newsletter, while only 47 percent of respondents in a recent CBS News poll supported reentering the Paris climate agreement, 70 percent said they supported reducing toxic chemicals in drinking water. That’s consistent with other polls showing that a majority of people think the federal government is doing too little to protect “lakes, rivers and streams,” and that an overwhelming majority of people—even 68 percent of Republicans—believe the federal government should play some role in “addressing differences across communities in their health risks from pollution and other environmental problems.”But every single time one of these rules is announced, companies and industry groups respond with the most ridiculous statements. Let’s look at just a few recent examples.“A group of coffee makers against banning methylene chloride,” Boston radio station WBUR reported in early April, “recently wrote the FDA saying, ‘True coffee aficionados in blind tastings’ prefer coffee decaffeinated with the chemical.” Who knows how this study was done—“True coffee aficionados” are not known for preferring decaf, period, hence a recent P.R. push to improve decaf’s image. Nick Florko, a reporter for health news website Stat, told WBUR that the coffee makers’ letter to the FDA was a “pretty funny claim if you consider the fact that we’re talking about coffee here that’s essentially rinsed in paint thinner.” And this says nothing at all about what happens to workers involved in the decaffeination process. (Methylene chloride has previously been shown to poison even trained workers wearing protective gear.)National Coffee Association president William Murray said something even weirder, telling CNN via email that banning methylene chloride “would defy science and harm American[s’] health.” His logic appeared to be that since all coffee consumption, including decaf, shows signs of reducing cancer risk overall, it’s not really a problem to decaffeinate coffee using a known carcinogen. That’s loopy even for industry pushback. For one thing, it’s easy to imagine that coffee could be good in general, and less good if you add poison to it. For another, coffee can also be decaffeinated without methylene chloride, using only water. Now let’s look at PFAS pushback. Knowing the EPA rules were in progress, the U.S. Chamber of Commerce in March launched the “Essential Chemistry for America” initiative, with the goal of “protecting ‘forever chemicals’ it deems ‘critical,’” according to E&E News. “We’re increasingly concerned that overly broad regulatory approaches threaten access to modern fluorochemistries, so we’re taking action to ensure their availability,” chamber vice president Marty Durbin said. Given that “access” language is typically used in a social and environmental justice context, restyling the regulation of poisons as threatening “access to modern fluorochemistries” is gutsy, to say the least. The private water industry is meanwhile throwing a fit about being asked to filter out PFAS. The rule will “throw public confidence in drinking water into chaos,” Mike McGill, president of water industry communications firm WaterPIO, told the AP. (You’d think the existence of PFAS in the water is what would tank public confidence, not the requirement that it be removed.) Then there’s the common threat from private water utilities—which, remember, turn a profit off providing a substance people can’t live without—that removing PFAS will increase people’s water bills. Robert Powelson, the head of the National Association of Water Companies, said that the costs of the federal regulation “will disproportionately fall on water and wastewater customers,” according to The Washington Post. “Water utilities do not create or produce PFAS chemicals,” Powelson added. “Yet water systems and their customers are on the front lines of paying for the cleanup of this contamination.”It’s true enough that water utilities are not the ones creating PFAS chemicals. On the other hand, there are lots of water contaminants that water utilities are responsible for filtering out if they want to keep making money from providing people with drinking water. Is there really any reason PFAS shouldn’t be among them? Saying that the cost of this regulation “will disproportionately fall on water and wastewater customers” shouldn’t be read as an expression of sympathy for disadvantaged households. The burden will fall on customers because the utilities will make sure of it. It’s a threat, and one that doesn’t mention the federal money from the Inflation Reduction Act that is being made available to help shoulder that burden. Those funds may well fall short, but that doesn’t change the fact that they’re paying for-profit entities to transition to removing something they ought to have been filtering out long ago. And even if this federal rule hadn’t been made, companies would probably have to start removing PFAS anyway, because they are facing increasingly expensive lawsuits over not doing so. (The water utilities, in turn, are suing polluters to cover remediation costs—another source of funding.)It’s worth emphasizing what PFAS chemicals actually do to people, particularly in light of the American Water Works Association’s assertion to the AP that the cost of removing the chemicals “can’t be justified for communities with low levels of PFAS.” Researchers are now pretty sure that PFAS exposure increases the risk of dying from cardiovascular disease. Studying people in northern Italy who drank PFAS-contaminated water, researchers also saw increased rates of kidney and testicular cancer. The Guardian report on this contained this disturbing finding too: Women with multiple children had lower levels of PFAS only because pregnancy transferred PFAS into their children’s bodies instead.Don’t let that get in the way of a good comms statement from industry groups, though. Remember: Forcing companies even to report their PFAS pollution, or remove PFAS from the water, is unfair.Good News/Bad NewsTwenty-nine-year-old Andrea Vidaurre has won the Goldman Environmental Prize for her work in environmental justice, pushing California to adopt new standards for truck and rail emissions that will curtail the air pollution harming working-class Latino communities in California’s Inland Empire. The United States has sided with petrostates in opposing production controls on plastic at the negotiations in Ottawa for a U.N. treaty to reduce plastic pollution. (Two weeks ago, I wrote about these negotiations, noting that the number of plastics industry lobbyists attending this session was not yet known. Now it is: 196 lobbyists from the fossil fuel and chemical industries registered for this round, according to the Center for International Environmental Law—a 37 percent increase from the number at the last session.)Stat of the Week9.6%That’s the percentage of the 250 most popular fictional films released between 2013 and 2022 in which climate change exists and a character depicted on screen knows it, according to a new “Climate Reality Check” analysis from Colby University and Good Energy. Read Sammy Roth’s newsletter about why climate change in movies is so important here.What I’m ReadingBig Oil privately acknowledged efforts to downplay climate crisis, joint committee investigation findsCongressional Democrats this week released a report confirming what news outlets have previously reported: Companies like Exxon knew about climate change very early on and covered it up. They also found in subpoenaed emails that Exxon tried to discredit reporting of its duplicity, while privately acknowledging that it was true:The new revelations build on 2015 reporting from Inside Climate News and the Los Angeles Times, which found that Exxon was for decades aware of the dangers of the climate crisis, yet hid that from the public.At the time, Exxon publicly rejected the journalists’ findings outright, calling them “inaccurate and deliberately misleading.” … But in internal communications, Exxon confirmed the validity of the reporting. In a December 2015 email about a potential public response to the investigative reporting, Exxon communications advisor Pamela Kevelson admitted the company did not “dispute much of what these stories report.” … “It’s true that Inside Climate News originally accused us of working against science but ultimately modified their accusation to working against policies meant to stop climate change,” Alan Jeffers, then a spokesperson for Exxon, wrote in a 2016 email to Kevelson. “I’m OK either way, since they were both true at one time or another.”Read Dharna Noor’s report in The Guardian.This article first appeared in Life in a Warming World, a weekly TNR newsletter authored by deputy editor Heather Souvaine Horn. Sign up here.

Op-ed: When it comes to food chemicals, Europe’s food safety agency and the FDA are oceans apart

The U.S. Food and Drug Administration (FDA) and the European Food Safety Authority (EFSA) are two major global agencies in charge of food chemical safety. It is common to hear that food chemical regulations in the EU are more protective of human health than in the U.S. The latest example is the recent ban of four food additives in California. The state’s Governor, Gavin Newsom, noted that the chemicals were already banned in the EU, implying that the lack of action by the FDA was putting the health of Californians at risk. We examined the FDA and EFSA’s responsibilities on food chemical safety to better understand why EFSA decisions are in general more protective of health. We specifically looked at the agencies’ approach to the safety of bisphenol-A (BPA) as an example of disparate decision-making.We found that in the EU the risk assessment and risk management of food chemicals are made by different entities: EFSA focuses on science and the European Commission decides on how the risk is managed. EFSA is independent to follow the science on BPA, for example, which resulted in three risk assessments with the last one showing greater harm to human health. In contrast, the FDA conducts both risk assessment and management and it is unclear how decisions are made. Over the years, the FDA has reviewed BPA studies but continued to maintain that its uses are safe.As the FDA undergoes a reorganization, the agency has a prime opportunity to increase transparency, collaborations and update its approach to evaluating food chemical safety. Separation of risk assessment and management Both in the EU and the U.S., the safety of chemicals allowed in food is based on the chemical’s inherent hazard and the level of exposure. If the risk is such that public health must be protected, a risk management decision is made, often via regulation. These decisions could range from banning chemicals to establishing a consumption level that would not increase health risks. "EFSA focuses on science and the European Commission decides on how the risk is managed ... In contrast, the FDA conducts both risk assessment and management and it is unclear how decisions are made."In the EU, the risk assessment and the risk management decisions are made by different entities. EFSA conducts risk assessments and the European Commission then makes the risk management decision based on EFSA’s findings. This separation allows the risk assessment to be grounded in science and the risk management to consider not only the science but also social, political, technological and economic factors, as well as the precautionary principle.In the U.S., the FDA conducts both risk assessment and management.Striking differences in assessing and managing riskThe EFSA relies on scientific panels composed of independent experts with high standards to limit conflicts of interest and bias. There are ten permanent panels and a scientific committee that supports their work. The scientific opinions are often unanimous, but when they’re not, minority reports are published in the EFSA Journal and also inform the European Commission’s risk management decisions.Unlike the EFSA, FDA staff review safety assessment and information provided by manufacturers. In a safety assessment there usually are four sections: toxicology, chemistry, environmental impact and policy; but it is unclear whether there is an epidemiologist among the reviewers. One FDA staff member from each section writes a memo with a summary of information and the conclusions. These memos inform the risk management decision about the use of a substance. The scientific evaluation is not always publicly available. It is also unclear how and by whom risk management decisions are made and whether the risk assessors are also involved in risk management. Prioritization of chemicals for reassessmentThe EFSA is mandated by law to re-evaluate all food additives authorized for use before 2009. The EFSA also identifies emerging risks and collects data about things like consumption, exposure and biological risk and responds to similar requests from member states.In the U.S., there is no legal mandate for the FDA to re-evaluate the use of the approximately 10,000 chemicals allowed in food, many of them authorized decades ago with little or no safety data. It is unclear if there is a process to identify emerging risks. The first reevaluation of chemicals was in response to President Nixon’s 1969 directive to reassess hundreds of substances the FDA determined to be generally recognized as safe. Only recently, the FDA took the initiative to re-evaluate the safety of partially-hydrogenated oil, Irgafos 168 and brominated vegetable oil. Other reevaluations have been in response to petitions from public interest organizations. BPA: A tale of two agenciesThe risk assessment of BPA — which has been linked to myriad health problems including cancer, diabetes, obesity, reproductive, immune system and nervous and behavioral problems — in food-contact materials is a good example of how two science-based agencies have made very different risk management decisions.EFSA conducted risk assessments of BPA in 2006, 2015 and 2023, each time at the request of the European Commission in response to new science. The second and third re-evaluations resulted in reductions in the daily allowed exposure of BPA due to new evidence showing greater harm to human health. To complete the process, the Commission recently published its proposed regulation of BPA, which includes a ban of most common uses in polycarbonate plastic and metal can coating.The FDA assessment of BPA has been riddled with missteps and lack of transparency. The FDA approved BPA for use in food contact applications in the early 1960s. It didn’t a draft safety assessment until 2008, at the request of its commissioner in light of findings by the National Toxicology Program and ongoing evaluations in Europe. FDA then asked its Science Board to review the draft and establish a subcommittee; there was also a public meeting and a report. The subcommittee, which included some members of the board and external experts, had several concerns about FDA’s assessment. In 2014, the FDA published a memo summarizing an updated safety assessment of BPA. The five-page memo cites the toxicology evaluation conducted in previous years and exposure assessment using an unpublished model. The agency concluded that the estimated consumption amount of BPA was safe to protect children and adults. This was the FDA's last safety assessment. Unlike the EFSA, the FDA process is less structured and open. At the FDA "it is also unclear how and by whom risk management decisions are made and whether the risk assessors are also involved in risk management."The FDA has conducted its own studies on BPA at different life stages and in different species. The agency was a member of the Consortium Linking Academic and Regulatory Insights on BPA Toxicity (CLARITY-BPA). Launched in 2012 by the National Institute of Environmental Health Sciences, the National Toxicology Program and the FDA, the aim of CLARITY was to combine a traditional regulatory toxicology study from the government and investigational studies from academics who wield more modern techniques. As part of CLARITY, the FDA also conducted a two-year guideline compliant study on BPA toxicity. In 2018, FDA concluded that “currently authorized uses of BPA continue to be safe for consumers.” This statement was based on the results of only the first year of the CLARITY two-year study conducted by FDA according to its toxicity guideline and did not include analysis of data produced by the multiple academic laboratories involved in the project. Furthermore, it was not based on an assessment of risk which also necessitates exposure data. Meanwhile, the results of CLARITY, including the academic studies largely ignored by the FDA, played an important role in EFSA’s latest BPA risk assessment. Unlike EFSA, the FDA has not made public the criteria applied to select the data, to evaluate and appraise the studies included in the hazard assessment, or the weight of evidence methodology used in its current reassessment of BPA. The lack of transparency was a concern previously expressed by FDA’s Science Board subcommittee in 2008.A “deep misunderstanding” of the risk assessment and management distinctionEFSA’s independence from risk management decisions and recruitment of independent experts to conduct risk assessments gives the agency the freedom to follow the science. By comparison, the FDA has stagnated.One explanation for such a difference would be FDA’s strong adherence to its historical decisions, rather than considering more recent science. This bias toward their own work is not conducive to change. Another explanation would be FDA scientists conflating risk assessment and risk management. In 2013, the FDA conducted a review of its chemical safety program and an external consultant noted that there appeared to be a “deep misunderstanding of the risk assessment – risk management distinction” among the staff. This observation is apparent in a commentary in Nature in 2010, where FDA toxicologists said that dismissing “out of hand” risk management factors such as economics, benefits of existing technologies, cost of replacing banned technologies and the toxic risk of any replacement “is, to say the least, insular, and surely imprudent in a regulatory setting.” The consultant added that FDA staff suggested that the agency “should not be too quick to adopt new scientific approaches.” Such an approach has likely deterred its scientists from acting on new evidence.FDA is undergoing a reorganization, including the creation of a new Human Food Program. Almost a year ago, the agency announced it was “embarking on a more modernized, systematic reassessment of chemicals with a focus on post-market review.” For this to be successful, the FDA should adopt updated processes and methods, include outside experts when it encounters challenging scientific or technical issues, increase collaboration with other agencies, and engage with stakeholders including consumers, academic institutions, public interest organizations and industry. But above all, the FDA must restore the public’s trust in the agency with a strong commitment to transparency in decision-making and clear separation between risk assessment and risk management.For more information check these summary tables.

The U.S. Food and Drug Administration (FDA) and the European Food Safety Authority (EFSA) are two major global agencies in charge of food chemical safety. It is common to hear that food chemical regulations in the EU are more protective of human health than in the U.S. The latest example is the recent ban of four food additives in California. The state’s Governor, Gavin Newsom, noted that the chemicals were already banned in the EU, implying that the lack of action by the FDA was putting the health of Californians at risk. We examined the FDA and EFSA’s responsibilities on food chemical safety to better understand why EFSA decisions are in general more protective of health. We specifically looked at the agencies’ approach to the safety of bisphenol-A (BPA) as an example of disparate decision-making.We found that in the EU the risk assessment and risk management of food chemicals are made by different entities: EFSA focuses on science and the European Commission decides on how the risk is managed. EFSA is independent to follow the science on BPA, for example, which resulted in three risk assessments with the last one showing greater harm to human health. In contrast, the FDA conducts both risk assessment and management and it is unclear how decisions are made. Over the years, the FDA has reviewed BPA studies but continued to maintain that its uses are safe.As the FDA undergoes a reorganization, the agency has a prime opportunity to increase transparency, collaborations and update its approach to evaluating food chemical safety. Separation of risk assessment and management Both in the EU and the U.S., the safety of chemicals allowed in food is based on the chemical’s inherent hazard and the level of exposure. If the risk is such that public health must be protected, a risk management decision is made, often via regulation. These decisions could range from banning chemicals to establishing a consumption level that would not increase health risks. "EFSA focuses on science and the European Commission decides on how the risk is managed ... In contrast, the FDA conducts both risk assessment and management and it is unclear how decisions are made."In the EU, the risk assessment and the risk management decisions are made by different entities. EFSA conducts risk assessments and the European Commission then makes the risk management decision based on EFSA’s findings. This separation allows the risk assessment to be grounded in science and the risk management to consider not only the science but also social, political, technological and economic factors, as well as the precautionary principle.In the U.S., the FDA conducts both risk assessment and management.Striking differences in assessing and managing riskThe EFSA relies on scientific panels composed of independent experts with high standards to limit conflicts of interest and bias. There are ten permanent panels and a scientific committee that supports their work. The scientific opinions are often unanimous, but when they’re not, minority reports are published in the EFSA Journal and also inform the European Commission’s risk management decisions.Unlike the EFSA, FDA staff review safety assessment and information provided by manufacturers. In a safety assessment there usually are four sections: toxicology, chemistry, environmental impact and policy; but it is unclear whether there is an epidemiologist among the reviewers. One FDA staff member from each section writes a memo with a summary of information and the conclusions. These memos inform the risk management decision about the use of a substance. The scientific evaluation is not always publicly available. It is also unclear how and by whom risk management decisions are made and whether the risk assessors are also involved in risk management. Prioritization of chemicals for reassessmentThe EFSA is mandated by law to re-evaluate all food additives authorized for use before 2009. The EFSA also identifies emerging risks and collects data about things like consumption, exposure and biological risk and responds to similar requests from member states.In the U.S., there is no legal mandate for the FDA to re-evaluate the use of the approximately 10,000 chemicals allowed in food, many of them authorized decades ago with little or no safety data. It is unclear if there is a process to identify emerging risks. The first reevaluation of chemicals was in response to President Nixon’s 1969 directive to reassess hundreds of substances the FDA determined to be generally recognized as safe. Only recently, the FDA took the initiative to re-evaluate the safety of partially-hydrogenated oil, Irgafos 168 and brominated vegetable oil. Other reevaluations have been in response to petitions from public interest organizations. BPA: A tale of two agenciesThe risk assessment of BPA — which has been linked to myriad health problems including cancer, diabetes, obesity, reproductive, immune system and nervous and behavioral problems — in food-contact materials is a good example of how two science-based agencies have made very different risk management decisions.EFSA conducted risk assessments of BPA in 2006, 2015 and 2023, each time at the request of the European Commission in response to new science. The second and third re-evaluations resulted in reductions in the daily allowed exposure of BPA due to new evidence showing greater harm to human health. To complete the process, the Commission recently published its proposed regulation of BPA, which includes a ban of most common uses in polycarbonate plastic and metal can coating.The FDA assessment of BPA has been riddled with missteps and lack of transparency. The FDA approved BPA for use in food contact applications in the early 1960s. It didn’t a draft safety assessment until 2008, at the request of its commissioner in light of findings by the National Toxicology Program and ongoing evaluations in Europe. FDA then asked its Science Board to review the draft and establish a subcommittee; there was also a public meeting and a report. The subcommittee, which included some members of the board and external experts, had several concerns about FDA’s assessment. In 2014, the FDA published a memo summarizing an updated safety assessment of BPA. The five-page memo cites the toxicology evaluation conducted in previous years and exposure assessment using an unpublished model. The agency concluded that the estimated consumption amount of BPA was safe to protect children and adults. This was the FDA's last safety assessment. Unlike the EFSA, the FDA process is less structured and open. At the FDA "it is also unclear how and by whom risk management decisions are made and whether the risk assessors are also involved in risk management."The FDA has conducted its own studies on BPA at different life stages and in different species. The agency was a member of the Consortium Linking Academic and Regulatory Insights on BPA Toxicity (CLARITY-BPA). Launched in 2012 by the National Institute of Environmental Health Sciences, the National Toxicology Program and the FDA, the aim of CLARITY was to combine a traditional regulatory toxicology study from the government and investigational studies from academics who wield more modern techniques. As part of CLARITY, the FDA also conducted a two-year guideline compliant study on BPA toxicity. In 2018, FDA concluded that “currently authorized uses of BPA continue to be safe for consumers.” This statement was based on the results of only the first year of the CLARITY two-year study conducted by FDA according to its toxicity guideline and did not include analysis of data produced by the multiple academic laboratories involved in the project. Furthermore, it was not based on an assessment of risk which also necessitates exposure data. Meanwhile, the results of CLARITY, including the academic studies largely ignored by the FDA, played an important role in EFSA’s latest BPA risk assessment. Unlike EFSA, the FDA has not made public the criteria applied to select the data, to evaluate and appraise the studies included in the hazard assessment, or the weight of evidence methodology used in its current reassessment of BPA. The lack of transparency was a concern previously expressed by FDA’s Science Board subcommittee in 2008.A “deep misunderstanding” of the risk assessment and management distinctionEFSA’s independence from risk management decisions and recruitment of independent experts to conduct risk assessments gives the agency the freedom to follow the science. By comparison, the FDA has stagnated.One explanation for such a difference would be FDA’s strong adherence to its historical decisions, rather than considering more recent science. This bias toward their own work is not conducive to change. Another explanation would be FDA scientists conflating risk assessment and risk management. In 2013, the FDA conducted a review of its chemical safety program and an external consultant noted that there appeared to be a “deep misunderstanding of the risk assessment – risk management distinction” among the staff. This observation is apparent in a commentary in Nature in 2010, where FDA toxicologists said that dismissing “out of hand” risk management factors such as economics, benefits of existing technologies, cost of replacing banned technologies and the toxic risk of any replacement “is, to say the least, insular, and surely imprudent in a regulatory setting.” The consultant added that FDA staff suggested that the agency “should not be too quick to adopt new scientific approaches.” Such an approach has likely deterred its scientists from acting on new evidence.FDA is undergoing a reorganization, including the creation of a new Human Food Program. Almost a year ago, the agency announced it was “embarking on a more modernized, systematic reassessment of chemicals with a focus on post-market review.” For this to be successful, the FDA should adopt updated processes and methods, include outside experts when it encounters challenging scientific or technical issues, increase collaboration with other agencies, and engage with stakeholders including consumers, academic institutions, public interest organizations and industry. But above all, the FDA must restore the public’s trust in the agency with a strong commitment to transparency in decision-making and clear separation between risk assessment and risk management.For more information check these summary tables.

Fiery 5,000 MPH Winds: Webb Maps Weather on Extreme Exoplanet WASP-43 b

WASP-43 b is cloudy on the nightside and clear on the dayside, with equatorial winds howling around the planet at 5,000 miles per hour. Sometimes...

This artist’s concept shows what the hot gas-giant exoplanet WASP-43 b could look like. WASP-43 b is a Jupiter-sized planet circling a star roughly 280 light-years away, in the constellation Sextans. The planet orbits at a distance of about 1.3 million miles (0.014 astronomical units, or AU), completing one circuit in about 19.5 hours. Because it is so close to its star, WASP-43 b is probably tidally locked: its rotation rate and orbital period are the same, such that one side faces the star at all times. Credit: NASA, ESA, CSA, Ralf Crawford (STScI)WASP-43 b is cloudy on the nightside and clear on the dayside, with equatorial winds howling around the planet at 5,000 miles per hour.Sometimes not finding something is just as exciting and useful as finding it. Take hot Jupiter WASP-43 b, for example. This tidally locked world has a searing-hot, permanent dayside and a somewhat cooler nightside. Astronomers using Webb to map the temperature and analyze the atmosphere around the planet expected to detect methane, a common carbon molecule, on the nightside. But there is clearly no sign of it. Why? The result suggests that supersonic winds of hot gas are blowing around from the dayside, thoroughly churning up the atmosphere, and preventing the chemical reactions that would otherwise produce methane on the nightside.This light curve shows the change in brightness of the WASP-43 system over time as the planet orbits the star. This type of light curve is known as a phase curve because it includes the entire orbit, or all phases of the planet.Because it is tidally locked, different sides of WASP-43 b rotate into view as it orbits. The system appears brightest when the hot dayside is facing the telescope, just before and after the secondary eclipse when the planet passes behind the star. The system grows dimmer as the planet continues its orbits and the nightside rotates into view. After the transit when the planet passes in front of the star, blocking some of the starlight, the system brightens again as the dayside rotates back into view.Credit: NASA, ESA, CSA, Ralf Crawford (STScI), Taylor Bell (BAERI), Joanna Barstow (The Open University), Michael Roman (University of Leicester)Webb Space Telescope Maps Weather on Planet 280 Light-Years AwayAn international team of researchers has successfully used NASA’s James Webb Space Telescope to map the weather on the hot gas-giant exoplanet WASP-43 b.Precise brightness measurements over a broad spectrum of mid-infrared light, combined with 3D climate models and previous observations from other telescopes, suggest the presence of thick, high clouds covering the nightside, clear skies on the dayside, and equatorial winds upwards of 5,000 miles per hour mixing atmospheric gases around the planet. The investigation is just the latest demonstration of the exoplanet science now possible with Webb’s extraordinary ability to measure temperature variations and detect atmospheric gases trillions of miles away.Tidally Locked “Hot Jupiter”WASP-43 b is a “hot Jupiter” type of exoplanet: similar in size to Jupiter, made primarily of hydrogen and helium, and much hotter than any of the giant planets in our own solar system. Although its star is smaller and cooler than the Sun, WASP-43 b orbits at a distance of just 1.3 million miles – less than 1/25th the distance between Mercury and the Sun.With such a tight orbit, the planet is tidally locked, with one side continuously illuminated and the other in permanent darkness. Although the nightside never receives any direct radiation from the star, strong eastward winds transport heat around from the dayside.Since its discovery in 2011, WASP-43 b has been observed with numerous telescopes, including NASA’s Hubble and now-retired Spitzer space telescopes.“With Hubble, we could clearly see that there is water vapor on the dayside. Both Hubble and Spitzer suggested there might be clouds on the nightside,” explained Taylor Bell, researcher from the Bay Area Environmental Research Institute and lead author of a study published on April 30 in Nature Astronomy. “But we needed more precise measurements from Webb to really begin mapping the temperature, cloud cover, winds, and more detailed atmospheric composition all the way around the planet.”This simplified diagram of an exoplanet phase curve shows the change in total brightness of a star–planet system as the planet orbits the star. The system looks brighter when more of the lit side of the planet is facing the telescope (full phase). It looks dimmer when more of the dark side is facing the telescope (new phase), when the planet is blocking some of the starlight (transit), and when light from the planet is blocked by the star (secondary eclipse).(Top) Diagram showing the change in a planet’s phase (the amount of the lit side facing the telescope) as it orbits its star.(Bottom) Three-dimensional graph showing the change in the total brightness of the star–planet system as the planet orbits its star. In this graph, known as a light curve, the horizontal plane is orbital location and the vertical axis is brightness.(Right) Scale bar. In both the orbital diagram and the light curve, color indicates the observed brightness of the star + planet: from dark purple (less amount of light detected) to white (more light detected).Researchers use phase curves to study variations in reflectivity and temperature of a planet with longitude (from one side to another), which can provide insight into the surface composition and atmospheric conditions of the planet.Credit: NASA, ESA, CSA, Dani Player (STScI), Andi James (STScI), Greg Bacon (STScI)Mapping Temperature and Inferring WeatherAlthough WASP-43 b is too small, dim, and close to its star for a telescope to see directly, its short orbital period of just 19.5 hours makes it ideal for phase curve spectroscopy, a technique that involves measuring tiny changes in brightness of the star-planet system as the planet orbits the star.Since the amount of mid-infrared light given off by an object depends largely on how hot it is, the brightness data captured by Webb can then be used to calculate the planet’s temperature.The team used Webb’s MIRI (Mid-Infrared Instrument) to measure light from the WASP-43 system every 10 seconds for more than 24 hours. “By observing over an entire orbit, we were able to calculate the temperature of different sides of the planet as they rotate into view,” explained Bell. “From that, we could construct a rough map of temperature across the planet.”The measurements show that the dayside has an average temperature of nearly 2,300 degrees Fahrenheit (1,250 degrees Celsius) – hot enough to forge iron. Meanwhile, the nightside is significantly cooler at 1,100 degrees Fahrenheit (600 degrees Celsius). The data also helps locate the hottest spot on the planet (the “hotspot”), which is shifted slightly eastward from the point that receives the most stellar radiation, where the star is highest in the planet’s sky. This shift occurs because of supersonic winds, which move heated air eastward.“The fact that we can map temperature in this way is a real testament to Webb’s sensitivity and stability,” said Michael Roman, a co-author from the University of Leicester in the U.K.To interpret the map, the team used complex 3D atmospheric models like those used to understand weather and climate on Earth. The analysis shows that the nightside is probably covered in a thick, high layer of clouds that prevent some of the infrared light from escaping to space. As a result, the nightside – while very hot – looks dimmer and cooler than it would if there were no clouds.This set of maps shows the temperature of the visible side of the hot gas-giant exoplanet WASP-43 b, as the planet orbits its star. The temperatures were calculated based on more than 8,000 brightness measurements of 5- to 12-micron mid-infrared light detected from the star-planet system by MIRI (the Mid-Infrared Instrument) on NASA’s James Webb Space Telescope. In general, the hotter an object is, the more mid-infrared light it gives off. Credit: NASA, ESA, CSA, Ralf Crawford (STScI), Taylor Bell (BAERI), Joanna Barstow (The Open University), Michael Roman (University of Leicester)Missing Methane and High WindsThe broad spectrum of mid-infrared light captured by Webb also made it possible to measure the amount of water vapor (H2O) and methane (CH4) around the planet. “Webb has given us an opportunity to figure out exactly which molecules we’re seeing and put some limits on the abundances,” said Joanna Barstow, a co-author from the Open University in the U.K.The spectra show clear signs of water vapor on the nightside as well as the dayside of the planet, providing additional information about how thick the clouds are and how high they extend in the atmosphere.Surprisingly, the data also shows a distinct lack of methane anywhere in the atmosphere. Although the dayside is too hot for methane to exist (most of the carbon should be in the form of carbon monoxide), methane should be stable and detectable on the cooler nightside.“The fact that we don’t see methane tells us that WASP-43 b must have wind speeds reaching something like 5,000 miles per hour,” explained Barstow. “If winds move gas around from the dayside to the nightside and back again fast enough, there isn’t enough time for the expected chemical reactions to produce detectable amounts of methane on the nightside.”The team thinks that because of this wind-driven mixing, the atmospheric chemistry is the same all the way around the planet, which wasn’t apparent from past work with Hubble and Spitzer.Reference: “Nightside clouds and disequilibrium chemistry on the hot Jupiter WASP-43b” by Taylor J. Bell, Nicolas Crouzet, Patricio E. Cubillos, Laura Kreidberg, Anjali A. A. Piette, Michael T. Roman, Joanna K. Barstow, Jasmina Blecic, Ludmila Carone, Louis-Philippe Coulombe, Elsa Ducrot, Mark Hammond, João M. Mendonça, Julianne I. Moses, Vivien Parmentier, Kevin B. Stevenson, Lucas Teinturier, Michael Zhang, Natalie M. Batalha, Jacob L. Bean, Björn Benneke, Benjamin Charnay, Katy L. Chubb, Brice-Olivier Demory, Peter Gao, Elspeth K. H. Lee, Mercedes López-Morales, Giuseppe Morello, Emily Rauscher, David K. Sing, Xianyu Tan, Olivia Venot, Hannah R. Wakeford, Keshav Aggarwal, Eva-Maria Ahrer, Munazza K. Alam, Robin Baeyens, David Barrado, Claudio Caceres, Aarynn L. Carter, Sarah L. Casewell, Ryan C. Challener, Ian J. M. Crossfield, Leen Decin, Jean-Michel Désert, Ian Dobbs-Dixon, Achrène Dyrek, Néstor Espinoza, Adina D. Feinstein, Neale P. Gibson, Joseph Harrington, Christiane Helling, Renyu Hu, Nicolas Iro, Eliza M.-R. Kempton, Sarah Kendrew, Thaddeus D. Komacek, Jessica Krick, Pierre-Olivier Lagage, Jérémy Leconte, Monika Lendl, Neil T. Lewis, Joshua D. Lothringer, Isaac Malsky, Luigi Mancini, Megan Mansfield, Nathan J. Mayne, Thomas M. Evans-Soma, Karan Molaverdikhani, Nikolay K. Nikolov, Matthew C. Nixon, Enric Palle, Dominique J. M. Petit dit de la Roche, Caroline Piaulet, Diana Powell, Benjamin V. Rackham, Aaron D. Schneider, Maria E. Steinrueck, Jake Taylor, Luis Welbanks, Sergei N. Yurchenko, Xi Zhang and Sebastian Zieba, 30 April 2024, Nature Astronomy.DOI: 10.1038/s41550-024-02230-xThe MIRI observation of WASP-43 b was conducted as part of the Webb Early Release Science programs, which are providing researchers with a vast set of robust, open-access data for studying a wide array of cosmic phenomena.The James Webb Space Telescope is the world’s premier space science observatory. Webb is solving mysteries in our solar system, looking beyond to distant worlds around other stars, and probing the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and the Canadian Space Agency.