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The imminent closure of Duke University’s herbarium sparked an outcry in the natural sciences community. But the loss to climate science could be even worse.
Kathleen Pryer did not watch March Madness this year.
That isn’t unusual in and of itself — Pryer describes herself as “not a basketball person,” though that might still raise a few eyebrows this time of year at Duke University, her place of employment. But the professor of biology has been a bit distracted lately. For the past few months, she’s been on defense, fending off a loss of her own: the pending closure of the school’s herbarium.
A herbarium (or plural, herbaria) is a collection of preserved plants, typically dried and mounted on sheets of rigid paper. The oldest existing collection in the world, the Gherardo Cibo herbarium in Rome, dates back to the mid 1500s; many U.S. collections are well over a century old. Browsing digitized herbaria online, one can easily get sucked in by their unintended whimsy; though the preserved plants are scientific specimens, traditionally collected by botanists to be used in the study of taxonomy during Western biology’s golden age of naming things, the pages remind me more of the pale, beautiful botanical illustrations in my childhood copy of Thumbelina.
Duke’s herbarium turns 103 this year and contains 825,000 specimens, making it one of the largest collections in the country. But back in mid-February, Susan Alberts, Duke’s dean of natural sciences, sent an email to Pryer, who curates the herbarium, and four other associated faculty members to inform them that “it’s in the best interests of both Duke and the herbarium to find a new home or homes for these collections.”
Though there had long been rumblings about the future of Duke’s herbarium — calls for “strategic plans,” hand-wringing about funds, worry about hiring new staff — the news came as both a shock and a slap in the face to the faculty, chief among them Pryer. “It’s some kind of little stinky plot,” she told me, adding, “I didn’t just roll over when it happened. I reached out to absolutely everybody I could think of.”
The news of Duke’s herbarium closure ricocheted through the tight-knit natural sciences community. Mason Heberling, an associate curator in the Section of Botany at the Carnegie Museum of Natural History, told me it should be a “wake-up call” for other researchers. The Duke herbarium is prestigious and hardly a “languishing collection,” he explained; researchers and faculty can easily slip into taking their herbaria for granted. “I’ve realized now that a huge part of my job as a curator will need to be explaining why these collections are important,” he said.
Swiftly, botanists and curators came to Duke’s defense. Opinion pieces and quotes decrying Duke’s decision appeared in the pages of The New York Times and Science. A petition went up on Change.org urging the school to reconsider its decision. Online fora burbled with discontent. “This may be the single worst thing to ever happen to Southeastern botany,” one post on Reddit read, with 64 additional comments piling on the administration for being “profit-obsessed business assholes.” “They could probably fund the entire thing with the salary of one head [basketball] coach,” grumbled another commenter.
The criticism of Duke’s decision is rooted in both a romantic nostalgia about herbaria — the same way you might feel fondly about hand-painted globes or cabinets of curiosities — and a very modern sense of scientific urgency. Researchers have only recently started leveraging the collections as invaluable pieces of data in the greater picture of climate change. “Herbaria are, in many ways, one of our best places to understand nature across space, time, and species,” Charles Davis, the curator of vascular plants at the nation’s largest private herbaria, at Harvard University, told me. “These collections are snapshots of events and occurrences in space and time that you just can’t easily replicate anywhere else. In fact, I would argue it’s impossible.”
Think of it this way: Worldwide, there are about 3,600 herbaria located in 193 different countries that collectively hold about 400 million specimens. Botanists estimate as much as half of the planet’s undiscovered flora could be found in herbaria backlogs. Barbara Thiers, the editor of the Index Herbariorum, a digital guide to the world’s collections, told me that when she was the director of the New York Botanical Garden Herbarium, “we had a huge room filled with unidentified species; I think there were 35,000 or 40,000 specimens in there.” That wasn’t for lack of effort — Thiers said that for many of the plant groups, there simply aren’t any working experts or published literature for curators to consult.
Because the climate is changing so fast, many plants in herbaria will go extinct before they’re formally discovered and named, a process known as a “dark extinction.” “It’s a very sobering feeling to touch the leaves of a tree that doesn’t exist anymore,” Erin Zimmerman, an evolutionary biologist and author of the forthcoming book Unrooted: Botany, Motherhood, and the Fight to Save an Old Science, told me, recalling coming across such a specimen in an herbarium while doing her own research. She likened herbaria to a library, but in her description I also heard echoes of a church: “The specimens are sometimes very old; you have to be very gentle with them, which just adds to the sense of holding something precious,” she went on.
Dwindling biodiversity is only the most obvious way herbaria are critical to 21st-century science. “Phenology, whether it’s when plants flower or when birds migrate, is one of the most important signals of climate change response,” Davis, the Harvard curator, said. Still, our long-term datasets aren’t very robust; research on how plants are changing with warming climates typically dates back only 25 to 30 years, tends to concentrate on the U.S. and Western Europe, and centers on easily observable phenomena, like the leafing out of woody trees. Researchers can turn to herbaria for centuries-old records of where certain plants grew and when they flowered, helping to bridge gaps in our understanding.
Heberling, of the Carnegie Museum of Natural History, tracks environmental changes in his research, but he didn’t start using herbaria until well after he’d obtained his Ph.D. Only then did he realize “herbarium specimens are incredible archives of the past,” he told me.
“You can look at the tiny pores, the stomata, on the leaves” of a plant in a herbarium and “see how that has changed over time with increased carbon dioxide,” Heberling said. Scientists have even used this method to create CO2 records.
Admittedly, climate science is still a relatively cutting-edge use case for the herbarium; according to Davis’ research, “global change biology” remains one of the least popular ways to leverage herbaria, well behind “taxonomic monographs” and “species distributions” that still dominate the field. Still, “there are things that, five to 10 years ago, I’d never even imagined we’d be doing today with herbarium specimens,” he told me.
As a result, Duke’s herbarium closure has made some question the university’s commitment to climate research — something that Alberts, the school’s natural sciences dean, emphatically refuted when I raised the question with her. She told me that a rough search revealed that only 23 of the 2,000 papers published by Duke researchers over the past few decades on climate change contained the word “herbarium” anywhere in them. “With my knowledge about all of the climate change research that’s been going on at Duke, the herbarium is not really central to whether or not Duke studies climate change,” she said.
For her part, Pryer has bristled at the administration’s insinuations that the herbarium is of limited use to students and faculty on campus. “You don’t measure a collection by who uses it,” she told me. “As I’ve been naughty enough to say, it’s not a toilet. People outside — the global community — uses it. That’s how you measure its value; things like 90 refereed publications a year [across all disciplines] cite the Duke collections.” Pryer can quickly tick off the climate projects that have come through the herbarium’s halls, including her recent supervision of a local high schooler’s research paper that found the pink lady’s slipper is flowering in the area 17 days earlier than it used to.
Duke is “not an appropriate home for a herbarium that is this large and valuable” for a number of reasons, according to Alberts, ranging from the need to hire new faculty to manage it (Pryer and several of her colleagues are approaching retirement) to the collection’s current building needing renovations. “I have had people email me saying, ‘I know you have enough money, I know you have the facilities.’ I’m like, ‘I’m sorry, you should tell me who you’re talking to, because we don’t,’” Alberts said. She added that she plans to be personally involved in finding the right home for Duke’s herbarium over the next several years.
After all, it’s not like the potential untapped climate records in the Duke collection are being destroyed (though both Pryer and Davis told me they’ve had deans wonder aloud if they could be, since many herbaria are now digitized). The goal is only to move the collection somewhere where it might be better utilized.
Thiers, though, said this is exactly what makes the natural science community so alarmed. As the collection is split up, ideally, the Index Herbariorum would record where Duke’s specimens get sent so scientists can still find them. But when new collections absorb the materials, curators will weed out duplicates, sending unneeded pages elsewhere — at which point specimens can fall between the cracks. “Before you know it, individual specimens will be lost,” Thiers said. “I can almost guarantee that as these secondary moves happen, people will not keep up with the database records.”
There is also a worst-case scenario everyone seemed nervous to mention: that Duke’s collection, in whole or in part, will end up in storage somewhere. Herbarium specimens are extremely susceptible to insect damage and must be kept in expensive, climate-controlled cabinets and rooms. “If they’re putting boxes in a storage storeroom someplace, they’ll be worthless in no time,” Thiers warned. The unidentified plants and uncollected climate data — all of it could be lost. And the cruelest part? Scientists wouldn’t even know what they are losing; it’s a dark extinction of a dark extinction.
When I spoke with Alberts, she said there were no updates on the administration’s plans for the herbarium. She expressed sympathy, though, for the faculty who oppose the administration’s decision. The herbarium “is their life’s work, and it’s important that they have a voice in this process,” she said.
Pryer is determined to keep fighting, even if this isn’t exactly how she’d pictured spending her golden years at Duke. “It’s having an impact on my research and on my health,” she told me. “It’s been pretty unrelenting. I’m anxious for something to resolve.”
She looked tired. There was a faculty meeting later in the day, and she hoped she’d be able to get more clarity about the administration’s decision then. “I don’t want this to go on forever,” she said. “But I also don’t want there to be a decision that makes Duke look insane.”
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On federal layoffs, copper tariffs, and Texas flood costs
Current conditions: Three people were killed in southern New Mexico after heavy rains on Tuesday caused flooding • Parts of the western Mediterranean Sea are 12.6 degrees Fahrenheit warmer than average • Search operations are underway for 30 people missing in India’s Himachal Pradesh state following flash floods and landslides.
The Supreme Court on Tuesday lifted a lower court ruling that had blocked mass layoffs of federal workers, clearing the way for a significant reduction in the civil service. Justice Ketanji Brown Jackson was the only dissenting vote, writing that the court had a “demonstrated enthusiasm for greenlighting this President’s legally dubious actions in an emergency posture.” Technically, SCOTUS’ ruling is only temporary, and the case could eventually return for the court to consider at a later date, with Justice Sonia Sotomayor noting, “The plans themselves are not before this Court, at this stage, and we thus have no occasion to consider whether they can and will be carried out consistent with the constraints of law.” But “in practice,” the court’s move allows President Trump to “pursue his restructuring plans, even if judges later determine that they exceed presidential power,” The New York Times writes.
The Trump administration has signaled its intention to reduce the workforce by 107,000 employees in the next fiscal year. It plans the steepest cuts for the Department of Education, the Office of Personnel Management, and the General Services Administration, but roles at the National Aeronautics and Space Administration, National Science Foundation, and Department of Energy are also up for reductions. As I’ve previously written, such cuts to the civil service will long outlast President Trump. “It will be very difficult, if not impossible, to restore the kind of institutional knowledge that’s being lost,” Jacqueline Simon, policy director of the American Federation of Government Employees, the largest union of federal government workers, told me.
President Trump announced on Tuesday that he intends to impose a 50% tariff on copper, a move that follows earlier tariffs on steel and aluminum. The process for imposing those tariffs, my colleague Matthew Zeitlin notes, involves recognizing that the product being tariffed is “essential to national security, and thus that the United States should be able to supply it on its own.” But while a steep new tariff could incentivize increased copper mining in the United States, such mines can take years to open, and copper must be smelted and refined before it can be used — an industry that is currently at capacity in the U.S. and dominated by China. Nevertheless, copper is crucial for “a broad array of electrical technologies, including transmission lines, batteries, and electric motors,” Matthew writes. “Electric vehicles contain around 180 pounds of copper on average.”
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The death toll in the Texas floods rose to over 100 on Tuesday, with Governor Greg Abbott telling reporters that another 161 people remain unaccounted for in Kerr County. Already one of the deadliest floods in modern U.S. history, the disaster is also set to be one of the costliest, with AccuWeather estimating total damage and economic loss between $18 billion and $22 billion. “The damage, impacts on future tourism, cost of search and recovery efforts, extensive cleanup that will be needed, as well as insurance claims after this catastrophic flash flood, will have long-lasting economic impacts in the Hill Country region of Texas,” AccuWeather Chief Meteorologist Jonathan Porter said in a statement.
As I wrote on Tuesday, the Texas floods were a disaster despite the forecasting, not because of it. While some global weather models underestimated the storm, NOAA’s cutting-edge specialized models “got this right,” UCLA and UC Agriculture and Natural Resources climate scientist Daniel Swain told me. Funding for those models — as well as research into severe thunderstorms and rainstorms like the one in Texas — is set to be zeroed out in the Trump administration’s 2026 budget.
The Department of Energy has hired three scientists who are among the minority of experts to doubt or downplay the impacts of human activity on global warming, The New York Times has learned. The scientists include physicist Steven E. Koonin, the author of the bestselling book Unsettled: What Climate Science Tells Us, What it Doesn’t and Why it Matters, which has been criticized for “not [comporting] with the evidence”; meteorologist Roy Spencer, the author of The Great Global Warming Blunder: How Mother Nature Fooled the World’s Top Climate Scientists, which alleges IPCC researchers made a “mix-up between cause and effect when analyzing cloud and temperature variations”; and atmospheric scientist John Christy, who’s been accused of using misleading graphs to downplay the extent of human activity on climate change. The New York Times was unable to immediately learn “what the three scientists were working on or whether they were being paid,” but the hires come at a time when the federal government is also laying off long-tenured climate and atmospheric scientists as well as removing mentions of climate change from government websites.
China is constructing nearly three-quarters of all solar and wind power projects being built globally, according to a new report by the Global Energy Monitor. Of about 689 gigawatts currently under construction worldwide, 510 gigawatts of utility-scale solar and wind were within China’s borders, the report found. Additionally, China accounts for 29% of all planned wind and solar projects worldwide, followed closest by Brazil, at just over 9%.
China’s wind and solar capacity surpassed its coal and gas capacity for the first time during the first quarter of 2025, supplying 23% of the country’s electricity consumption, the report adds. Even offshore wind, a “small portion of China’s overall renewable capacity,” now contributes over 50% of the overall offshore wind capacity in construction worldwide. You can read the full report here.
Image: Studio Pizza/Unsplash
Cemeteries are “a mosaic of different habitats. This means that species from forests, hedgerows, grasslands, and even fields can find substitute habitats there.” —Ingo Kowarik, an urban ecologist and retired professor at the Technische Universität Berlin, on the burgeoning field of cemetery biodiversity.
Jesse and Rob go back to basics on the steam engine.
Just two types of machines have produced the overwhelming majority of electricity generated since 1890. This week, we look at the history of those devices, how they work — and how they have contributed to global warming.
This is our second episode of Shift Key Summer School, a series of “lecture conversations” about the basics of energy, electricity, and the power grid for listeners of all backgrounds. This week, we dive into the invention and engineering of the world’s most common types of fossil- and nuclear-fueled power plants. What’s a Rankine cycle power station, and how does it use steam to produce electricity? How did the invention of the jet engine enable the rise of natural gas-generated electricity? And why can natural gas power plants achieve much higher efficiency gains than coal plants?
Shift Key is hosted by Jesse Jenkins, a professor of energy systems engineering at Princeton University, and Robinson Meyer, Heatmap’s executive editor.
Subscribe to “Shift Key” and find this episode on Apple Podcasts, Spotify, Amazon, YouTube, or wherever you get your podcasts.
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Here is an excerpt from our conversation:
Robinson Meyer: It’s interesting thinking about the deployment of steam and these Rankine cycle generators in the late 19th century for us as people who care about the power grid. These are interesting techniques as they’re deploying electricity for the first time. But the use of coal to convert water into steam and the use of steam power actually comes way earlier than any of this, right? Like, it’s steam. That is actually the 19th century — the core 19th century and late 19th century, especially — energy medium. And actually, the history of the 19th century energy is switching from wood and hydropower to coal-powered steam.
And already by the time that the Pearl Street station is built in New York, the United States is crisscrossed with steam engines. Our economy already runs on steam. It’s actually the application of steam and coal — which at that point are kind of old and fundamental technologies to economic function — to power generation. They didn’t have to make any huge discoveries around steam and coal. They were already using steam and coal in factories, they just weren’t intermediating it through the electricity grid.
Jesse Jenkins: That’s right. And in all these cases, you’re just trying to convert that steam, the expansion of that steam, into motion, whether that’s the pistons of a steam engine or the pistons of a reciprocating generator attached to a dynamo in Pearl Street, or, in a lot of factories, just a bunch of belts, right? That would then move equipment throughout the facility. It’s just a lot easier to move energy around, and more precise to do that as electricity. And so over time, the devices in industrial facilities all converted over to using electricity directly, and then you could generate your energy somewhere far away.
And this is the other, second advantage of steam turbines. What made Westinghouse so successful is that they have large economies of scale, so it’s a lot cheaper to generate power from a big steam turbine than the equivalent amount of power from a lot of little steam engines. And that wasn’t … I mean, that’s true for reciprocating engines, but they kind of top out, given their complexity.
The Pearl Strait station generators were in the 100-kilowatt scale. I think there were six of them, originally, so 600 kilowatts, and they only powered a few hundred lights, which is remarkable. These lights, the original lights, were incredibly inefficient, so it took something like 1,000 watts or more per light bulb. Whereas again, now we’re down to like, 10 to 15 watts in an efficient LED bulb. But anyway, they were in that kind of hundreds of watts scale, and that kind of maxed out the scale of the reciprocating engines. Steam turbines you could increase and increase and increase into the megawatt scale, and by doing that utilities or generators were able to lower the cost of energy while expanding customer bases.
Mentioned:
Powering the Dream: The History and Promise of Green Technology, by Alexis Madrigal
This episode of Shift Key is sponsored by …
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Music for Shift Key is by Adam Kromelow.
The Senate told renewables developers they’d have a year to start construction and still claim a tax break. Then came an executive order.
Renewable energy advocates breathed a sigh of relief after a last-minute change to the One Big Beautiful Bill Act stipulated that wind and solar projects would be eligible for tax credits as long as they began construction within the next 12 months.
But the new law left an opening for the Trump administration to cut that window short, and now Trump is moving to do just that. The president signed an executive order on Monday directing the Treasury Department to issue new guidance for the clean electricity tax credits “restricting the use of broad safe harbors unless a substantial portion of a subject facility has been built.”
The broad safe harbors in question have to do with the way the government defines the “beginning of construction,” which, in the realm of federal tax credits, is a term of art. Under the current Treasury guidance, developers must either complete “physical work of a significant nature” on a given project or spend at least 5% of its total cost to prove they have started construction during a given year, and are therefore protected from any subsequent tax law changes.
As my colleague Matthew Zeitlin previously reported, oftentimes something as simple as placing an order for certain pieces of equipment, like transformers or solar trackers, will check the box. Still, companies can’t just buy a bunch of equipment to qualify for the tax credits and then sit on it indefinitely. Their projects must be up and operating within four years, or else they must demonstrate “continuous progress” each year to continue to qualify.
As such, under existing rules and Trump’s new law, wind and solar developers would have 12 months to claim eligibility for the investment or production tax credit, and then at least four years to build the project and connect it to the grid. While a year is a much shorter runway than the open-ended extension to the tax credits granted by the Inflation Reduction Act, it’s a much better deal than the House’s original version of the OBBBA, which would have required projects to start construction within two months and be operating by the end of 2028 to qualify.
Or so it seemed.
The tax credits became a key bargaining chip during the final negotiations on the bill. Senator Lisa Murkowski of Alaska fought to retain the 12-month runway for wind and solar, while members of the House Freedom Caucus sought to kill it. Ultimately, the latter group agreed to vote yes after winning assurances from the president that he would “deal” with the subsidies later.
Last week, as all of this was unfolding, I started to hear rumors that the Treasury guidance regarding “beginning of construction” could be a key tool at the president’s disposal to make good on his promise. Industry groups had urged Congress to codify the existing guidance in the bill, but it was ultimately left out.
When I reached out to David Burton, a partner at Norton Rose Fulbright who specializes in energy tax credits, on Thursday, he was already contemplating Trump’s options to exploit that omission.
Burton told me that Trump’s Treasury department could redefine “beginning of construction” in a number of ways, such as by removing the 5% spending safe harbor or requiring companies to get certain permits in order to demonstrate “significant” physical work. It could also shorten the four-year grace period to bring a project to completion.
But Burton was skeptical that the Treasury Department had the staff or expertise to do the work of rewriting the guidance, let alone that Trump would make this a priority. “Does Treasury really want to spend the next couple of months dealing with this?” he said. “Or would it rather deal with implementing bonus depreciation and other taxpayer-favorable rules in the One Big Beautiful Bill instead of being stuck on this tangent, which will be quite a heavy lift and take some time?”
Just days after signing the bill into law, Trump chose the tangent, directing the Treasury to produce new guidance within 45 days. “It’s going to need every one of those days to come out with thoughtful guidance that can actually be applied by taxpayers,” Burton told me when I called him back on Monday night.
The executive order cites “energy dominance, national security, economic growth, and the fiscal health of the Nation” as reasons to end subsidies for wind and solar. The climate advocacy group Evergreen Action said it would help none of these objectives. “Trump is once again abusing his power in a blatant end-run around Congress — and even his own party,” Lena Moffit, the group’s executive director said in a statement. “He’s directing the government to sabotage the very industries that are lowering utility bills, creating jobs, and securing our energy independence.”
Industry groups were still assessing the implications of the executive order, and the ones I reached out to declined to comment for this story. “Now we’re circling the wagons back up to dig into the details,” one industry representative told me, adding that it was “shocking” that Trump would “seemingly double cross Senate leadership and Thune in particular.”
As everyone waits to see what Treasury officials come up with, developers will be racing to “start construction” as defined by the current rules, Burton said. It would be “quite unusual” if the new guidance were retroactive, he added. Although given Trump’s history, he said, “I guess anything is possible.”