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Dagomar Degroot

@dagomardegroot.bsky.social
2.5K followers 154 following 197 posts

Professor of environmental history at Georgetown University. Creator, "The Climate Chronicles." Author of the new book, "Ripples on the Cosmic Ocean." Interested in all things climate change, outer space, existential risk, and past for present.

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Dagomar Degroot @dagomardegroot.bsky.social · 22/09/2026
As @zekehausfather.com and David Wallace-Wells put it: although worst-case scenarios for #ClimateChange seem less likely than they once did, they're still very much in play. That was also my takeaway while writing the scenarios in After2c (after2c.com). www.nytimes.com/2026/09/22/o...
nytimes.com
Opinion | Climate Catastrophe Is Still on the Table
Harrowing temperature increases remain unnervingly possible.
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Royal Historical Society @royalhistsoc.org · 20/09/2026
Coming up this week, the Society hosts two events on history and the environment. The first, at 1pm on Thurs 24th, offers 'Historical Context' on 'The Climate Crisis': bit.ly/3V4lgKf With panellists @dagomardegroot.bsky.social, @sadiahqureshi.bsky.social and bsky.app/profile/elly... All welcome.
eventbrite.co.uk
Historical Context: The Climate Crisis
A panel discussion, hosted by the Royal Historical Society, in which expert historical researchers provide context for current events.
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Zeke Hausfather @zekehausfather.com · 16/09/2026
All the September dynamical ENSO models (including SINTEX) are now in, and they give a 100% chance of a record event this year using the Oceanic Niño Index (ONI) metric:
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Kevin Anchukaitis @thirstygecko.bsky.social · 10/09/2026
Projected amplification of global warming by warming-induced greenhouse gas emissions '[Warming-induced emissions] could add 0.2 °C–0.4 °C of warming by 2100' iopscience.iop.org/article/10.1...
iopscience.iop.org
Projected amplification of global warming by warming-induced greenhouse gas emissions
Projected amplification of global warming by warming-induced greenhouse gas emissions, Abernethy, Sam, Monteverde, Danielle, Schädel, Christina, Buma, Brian, Duffy, Philip B, Jackson, Robert B, Natali, Susan M, Ocko, Ilissa, Rogers, Brendan M, Poulter, Benjamin
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Dagomar Degroot @dagomardegroot.bsky.social · 09/09/2026
There's been some really interesting debate here on #AI in history. Here are five basic things to keep in mind. 1. Terminology matters! AI is not the same as LLMs. Machine learning is a branch of AI. Deep learning is a branch of machine learning. LLMs are a family of deep-learning systems. (1/10)
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Dagomar Degroot @dagomardegroot.bsky.social · 09/09/2026
I'm grateful to the Conversation for assembling this unique guide to #SpaceWeather. It's based on five recent articles, including my new piece drawing from my book, Ripples on the Cosmic Ocean. (1/2) #EnvHist #SolarStorms theconversation.com/space-weathe...
theconversation.com
Space weather can cause both beautiful auroras and infrastructure challenges – 5 essential reads on protecting life and technology
A massive solar flare could seriously disrupt life on Earth – but new NASA missions and others in development will help monitor the Sun.
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Dagomar Degroot @dagomardegroot.bsky.social · 02/09/2026
I really hope I got this wrong. But I believe the stage is set for a global food crisis, the likes we haven’t seen since the 1970s. Will it materialize in the coming year? In this article, I break it down. #ElNino #GlobalWarming #Iran #Ukraine sciencepolitics.org/2026/09/02/t...
sciencepolitics.org
The Coming Global Food Crisis? - Science Politics
A Warning...
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Tennant Reed @tennantreed.bsky.social · 27/08/2026
The project is a website, after2c.com, drawing on published research, recent history and speculative fiction in a very interesting way. By Prof @dagomardegroot.bsky.social and his Existential Risk class students.
after2c.com
After 2C - Histories of the Future of Global Warming
An interactive exploration of five plausible, research-grounded climate futures, written as history papers looking back from the year 2100.
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NiCHE Canada @nichecanada.bsky.social · 20/08/2026
Today @dagomardegroot.bsky.social introduces After 2C, Histories of the Future of Global Warming Can today’s history students shape the future of climate change? And how will the history students of the future remember global warming? niche-canada.org/2026/08/20/i... #envhist #climatechange
niche-canada.org
Introducing: After 2C, Histories of the Future of Global Warming
Can history students shape our climate future? Explore After2C, an interactive site using plausible future histories to examine global warming, geoengineering, and climate hope.
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Dr. Lucky Tran @luckytran.com · 17/08/2026
US child vaccination rates have plunged since before the pandemic, with kindergarten classrooms in more than 70% of counties now lacking herd immunity against measles.
US choropleth map showing percentage change in MMR or overall vaccination rates since before the pandemic, by county. Decreases are shown in pink, increases in green.
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Dagomar Degroot @dagomardegroot.bsky.social · 13/08/2026
The worst risks associated with #ClimateChange are linked to "tipping elements," parts of the climate system that could quickly and all but irreversibly enter new states. I created a website that maps these tipping elements and collects the newest research about them. www.climatetippingpoints.com
climatetippingpoints.com
Climate Tipping Points
Explore an interactive atlas of climate tipping points and tipping elements, with continuously updated research on thresholds, consequences, uncertainty, and connections.
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Dagomar Degroot @dagomardegroot.bsky.social · 12/08/2026
I’m thrilled to introduce a major new project: “After 2C.” It’s an interactive website that tries to answer a simple question: how will the history students of the future write about global warming in our century? (1/5) #ClimateChange #GlobalWarming #ElNino #EnvHist after2c.com
after2c.com
After 2C - Histories of the Future of Global Warming
An interactive exploration of five plausible, research-grounded climate futures, written as history papers looking back from the year 2100.
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Kat Long @katlong.bsky.social · 28/07/2026
New from me: Climate change is eating away at Svalbard's largest whalers' graveyard, threatening bones and textiles preserved in the 17th-century burials as well as the scientific data embedded in them 🧪⚱️❄️
nationalgeographic.com
Thawing permafrost is threatening Svalbard's 'corpse point'
Human bones and artifacts from the largest whalers’ graveyard in the archipelago are at risk of disintegrating.
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Dagomar Degroot @dagomardegroot.bsky.social · 13/07/2026
My take on #America250. Both trends and anomalies in weather have shaped the history of the United States. And if we don't restore efforts to slash greenhouse gas emissions, #ClimateChange could make for a grim 300th. sciencepolitics.org/2026/07/13/h... #ClimateChange #America250
sciencepolitics.org
How Climate Change and Weather Shaped 250 Years of U.S. History - Science Politics
Cold, rain, drought, and warming have both helped and harmed Americans' efforts at pivotal moments.
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NiCHE Canada @nichecanada.bsky.social · 06/07/2026
ICYMI: @harrycroft.bsky.social reflects on his experience at our Canadian History of the Enviornment Summer School in PEI! niche-canada.org/2026/07/04/s... #envhist #cdnhist #PEI
niche-canada.org
Speed CHESS 2026: A First-Timer's Account
Harrison Croft, a Germany-based historian, attended the CHESS meeting in PEI, exploring climate resilience, parabolic sand dunes, and local environmental histories.
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Zeke Hausfather @zekehausfather.com · 06/07/2026
July ECMWF runs are in and forecast an even more extreme El Niño event than the prior June runs. ENSO3.4 region temperatures reach 3.9C in December, and forecasts are around 0.3C warmer than they were in June.
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Simon Evans @drsimevans.carbonbrief.org · 02/07/2026
Did you know? Renewables have just overtaken coal as the world's largest source of electricity 34% – global renewable share, up 2x in 20yrs 48% – EU 37% – China 26% – US 24% – India
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Dagomar Degroot @dagomardegroot.bsky.social · 02/07/2026
Want to write a peer-reviewed, Oxford Intersections article on the #EnvHist of disasters? Check out our call for papers! Oxford Intersections offers a quick, respected, high-impact publishing format - perfect for new research in environmental history. academic.oup.com/oxford-inter...
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Dagomar Degroot @dagomardegroot.bsky.social · 24/06/2026
Clare is a remarkable person in so many ways. This is vital reading.
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Dagomar Degroot @dagomardegroot.bsky.social · 18/06/2026
Big histories of #ClimateChange are always full of mistakes, partly because climate science is constantly changing. Because my "Climate Chronicles" is not a book, I can fix my errors. I've now published a list of the revisions I plan to make this year. #EnvHist theclimatechronicles.com/revisions/
theclimatechronicles.com
Revisions - The Climate Chronicles
The Climate Chronicles attempts to explain how climate change shaped the history of our species. That’s a daunting challenge, for at least three reasons.
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Kevin Anchukaitis @thirstygecko.bsky.social · 11/06/2026
This really would be the end of science in the US marginalrevolution.com/marginalrevo...
marginalrevolution.com
The Nationalization of American Science - Marginal REVOLUTION
OMB, joined by some forty grantmaking agencies—NSF, HHS, DOE, NASA, DOD among them—has proposed a sweeping rewrite of the rules governing all federal grants, the Regulation for Federal Financial Assis...
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Dagomar Degroot @dagomardegroot.bsky.social · 11/06/2026
Today at 5 PM EST! Join @amandagefter.bsky.social and me for a conversation that spans Earth and the solar system, exploring how natural and human histories intersect. We'll talk about everything from #climatechange to #alien civilizations - it should be fun. #EnvHist #Astronomy luma.com/apv6a38z
luma.com
Space Weather and the Course of History · Zoom · Luma
Often when we think of space we think of “out there.” The wonders beyond. But out there includes us! Let’s talk about the weather. On Earth it can delight or…
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NiCHE Canada @nichecanada.bsky.social · 22/05/2026
Event - Reflections on Resilience: 20,000 Years of Climate History A Climate History Plenary with @dagomardegroot.bsky.social Part of #CHESS2026 Sunday – 31 May 2026 – 17:30-18:45 ADT Murphy Student Centre 110 (McMillan Hall) – University of Prince Edward Island niche-canada.org/2026/05/22/e...
niche-canada.org
Event - Reflections on Resilience: 20,000 Years of Climate History
31 May 2026 - Charlottetown, Prince Edward Island - Dr. Dagomar Degroot is a leading climate historian from Georgetown University. He has published several high-impact, award-winning books on climate ...
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Nature Portfolio @natureportfolio.nature.com · 12/05/2026
A study in Nature Sustainability shows sea-level rise is already causing population retreat in coastal Louisiana and uses geological history and demographic data to argue that early, planned relocation can guide global climate adaptation. go.nature.com/4eHOh6q 🌍🌊🧪
This is figure 4, which shows population change along the US Gulf Coast, Louisiana to Florida (2000–2024).
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Dagomar Degroot @dagomardegroot.bsky.social · 12/05/2026
As @climatechirper.bsky.social says, "The deliberate actions of colonialists in the 1870s disrupted local systems that communities relied on for being resilient to climate variations." So, it's wrong to claim that it was #ElNino that killed millions in 1877. www.washingtonpost.com/weather/2026...
washingtonpost.com
A super El Niño wiped out millions of people in 1877. Are we better prepared now?
The climatic phenomenon is expected to return this year, but a lot has changed since what might have been the worst environmental disaster in human history.
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Dagomar Degroot @dagomardegroot.bsky.social · 09/05/2026
No. Instead of thinking, "what do people want to hear, and how can I give it to them?", politicians should ask, "what do I think is important, how can I explain why it's important, and how can I offer solutions?" Authenticity matters, now more than ever. #Climate www.nytimes.com/2026/05/09/o...
nytimes.com
Opinion | Forget Climate Change. Democrats Need to Talk About Other Issues.
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Dagomar Degroot @dagomardegroot.bsky.social · 07/05/2026
Had I been interviewed for this article (rather than merely quoted), I would have said: We don't seek signs of #ClimateChange in early modern (EM) art because today's climate is changing. We seek it because the early modern climate changed. (1//2) www.jns.org/feature/once...
jns.org
Once jeered as too pretty, Impressionism is now marshaled in climate-change activism
Even as they bring contemporary politics into the story, museums tend to overlook the antisemitism that divided Impressionists over the Dreyfus Affair in the late 19th century.
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Andy Saunders - Apollo Remastered @andysaunders-1.bsky.social · 06/05/2026
This is incredible. The new NASA image release from #Artemis includes a sequence of 'Hello World' still photographs. I've been processing / animating them and here's what the original didn't show us: Satellites, including their solar arrays, lightning storms and dancing aurora!
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Dagomar Degroot @dagomardegroot.bsky.social · 01/05/2026
"Project Hail Mary" imagines how an environmental change on the Sun spurs an effort to protect the environment of Earth. In a way, it's the thrilling, fictional counterpart to my new book, "Ripples on the Cosmic Ocean." #EnvHist #ProjectHailMary sciencepolitics.org/2026/05/01/p...
sciencepolitics.org
Project Hail Mary Tells a True Story About Humanity’s Past and Future - Science Politics
Changes in solar environments could pose serious risks to modern life.
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Kate Marvel @drkatemarvel.bsky.social · 22/04/2026
In honor of Earth Day: a thread of environmental wins
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Dr. Tripti Bhattacharya @triptychphrases.bsky.social · 22/04/2026
How can records of the past inform our understanding of extreme events? Join the National Academies on April 29 for a webinar releasing a new report on a proposed Center for Paleoenvironmental Records of Extreme Events (CPREE). Register: events.nationalacademies.org/46602
events.nationalacademies.org
Functions and Criteria for a New Center for Paleoenvironmental Records of Extreme Events: Report Release Webinar
Register for this event from the National Academies of Sciences, Engineering, and Medicine.
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Chris Baraniuk @chrisbaraniuk.com · 15/04/2026
It's a little hard to fit everything into news stories like this but something I wanted to spell out - Prof Yasuyuki Aono was an *incredibly* dedicated person, by all accounts, who brought us the now-famous cherry blossom climate indicator. www.theguardian.com/world/2026/a...
theguardian.com
After 1,200 years, cherry blossom record to live on despite Japanese scientist’s death
Prof Yasuyuki Aono’s meticulous work charted shifting bloom dates as a marker of climate change
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Dagomar Degroot @dagomardegroot.bsky.social · 15/04/2026
Collapse! Mega-drought! The 16th episode of The Climate Chronicles explores whether a wave of drying brought about the collapse of the world's first empire, 4200 years ago. It's a huge episode: more than 8000 words and 65 mins of audio. #EnvHist theclimatechronicles.com/2026/04/07/e...
theclimatechronicles.com
Episode 16: Megadrought in Mesopotamia - The Climate Chronicles
More than 4,000 years ago, a wall seems to have gone up across what is now northern Iraq.
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Dagomar Degroot @dagomardegroot.bsky.social · 14/04/2026
This second edition is essential reading - for everyone. If there’s one book I’d recommend in environmental history, it might be this. With an introduction by @brdemuth.bsky.social! #EnvHist
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Dagomar Degroot @dagomardegroot.bsky.social · 10/04/2026
Excited to discuss "Ripples on the Cosmic Ocean" at Georgetown on Monday. And talk about timing. Seeing the Moon this morning, knowing that the #Artemis astronauts just flew around it, gave me the most surreal sense of Earth's precarity in a dynamic universe. events.georgetown.edu/eia/event/ri...
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Dagomar Degroot @dagomardegroot.bsky.social · 09/04/2026
The combination of a very strong #ElNiño - which should reduce harvests across Asia, Australia, Africa, and parts of the Americas - with soaring fertilizer and fuel prices, owing to the ongoing closure of the Strait of #Hormuz, could make for a devastating year of food shortages and social unrest.
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Dan Immergluck @danimmergluck.bsky.social · 08/04/2026
Brutal.
A WHOLE CIVILIZATION
WILL DIE TONIGHT
My son needs lunch, and I have to put his backpack together, but a whole civilization will die tonight, so I'm wondering if they've closed their schools.
Like, a snow day, maybe, except instead of snow it's
"keep your children home so if you die, you die together" — instead of "well open back up once the plows have cleared" it's
"we don't know if we'll be here tomorrow, hold your babies tight."
It's just "talk" I'm told, which I've been told before.
"It's how the president makes his deals." But I've never heard anyone talk about other human beings this way, and I'm not certain I can look my son in the eyes if we all agree to stomach it one more time.
A civilization will die tonight, but as I zip up his backpack and kiss him off to school I think: if this is what we call leadership then I'm not entirely sure ours isn't already dead.
@michaelfdubois
Mukad A QuBoy
@michacifdubois
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Dagomar Degroot @dagomardegroot.bsky.social · 08/04/2026
Recently, I enjoyed chatting about the history, and possible future, of #ClimateChange. First - did drought cause social unrest and conflict in the late Roman Empire? Tree ring evidence suggests maybe, but the textual evidence seems ambiguous. (1/2) www.newscientist.com/article/2520...
newscientist.com
Historians dispute link between drought and rebellion in Roman Britain
A study based on tree rings claimed that droughts played a role in events that led to the Roman withdrawal from Britain, but other researchers say that isn't backed up by historical evidence
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Ted Underwood @tedunderwood.com · 07/04/2026
I knew about the 1969 moon landing. And knew that news of the My Lai massacre came out in '69. But I had those events in separate boxes. Occurs to me now that it must have been disorienting to feel proud of (one aspect of) your country, while also deeply shamed by its crimes.
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Dagomar Degroot @dagomardegroot.bsky.social · 07/04/2026
Almost 60 years ago, the defining image of #Apollo was Earth rising above the Moon. Now, the iconic image from #Artemis may be the Earth setting behind the Moon. I hope there's no deeper meaning in that....
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Robert Reich @rbreich.bsky.social · 07/04/2026
“But ultimately, we will always choose Earth. We will always choose each other.” —Artemis II astronaut Christina Koch
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Dagomar Degroot @dagomardegroot.bsky.social · 06/04/2026
There's something uncanny about how different a picture can feel when you know that people took it, rather than robots. This is a Moon we haven't seen - or felt - in over 53 years. #Artemis
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Dagomar Degroot @dagomardegroot.bsky.social · 06/04/2026
This, from a version of "Ripples," is what the #Moon looks like through a small telescope: "On an ordinary autumn night, I crouch over a delicate refractor, waiting in breathless silence. Peering through my eyepiece, I admire faint stars glittering in the gloom, diamond-dust on black velvet. 1/3
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Dagomar Degroot @dagomardegroot.bsky.social · 04/04/2026
Earth is part of a mosaic of dynamic cosmic environments - or so I argue in “Ripples on the Cosmic Ocean.” And that’s partly why space exploration is so important. #Artemis
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Dagomar Degroot @dagomardegroot.bsky.social · 03/04/2026
A magnificent snapshot of one of the world’s most important relationships: Saharan sands on the left, the Amazon rainforest on the right. Carried west by the trade winds, the sand fertilizes the jungle, and the jungle helps stabilize Earth's climate - for now. #Artemis
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Maggie Koerth @maggiek.bsky.social · 02/04/2026
Reminder, we currently have people in space, heading toward the moon.
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David Grinspoon @drfunkyspoon.bsky.social · 02/04/2026
Amazing orbital view of the Artemis 2 launch, as seen from the GOES-19 satellite. 🧪
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Dagomar Degroot @dagomardegroot.bsky.social · 02/04/2026
Here's an essay-length review of 4 new books on the history of #ClimateChange, with my thoughts on how the scale of our analyses and the depth of our engagement with global warming alters the kinds of stories we can tell about history (and their accuracy). #EnvHst online.ucpress.edu/hsns/article...
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Dagomar Degroot @dagomardegroot.bsky.social · 01/04/2026
It will never stop being wild to me that it takes just 5 minutes to leave the atmosphere. It’s such a thin, tenuous veil that separates us from the void. #Artemis
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