Dagomar Degroot
@dagomardegroot.bsky.social
Professor of environmental history at Georgetown University. Creator, The Climate Chronicles podcast. Author of the new book, "Ripples on the Cosmic Ocean." Interested in all things climate change, outer space, existential risk, and past for present.
Pinned
Solar storms have influenced our history – an environmental historian explains how they could also threaten our future
From communications outages to a brush with nuclear war, solar events like flares and coronal mass ejections have shaped human history.
theconversation.com
My new book, "Ripples on the Cosmic Ocean," was published today! And here's a new article in @theconversation.com that explains how #solarstorms have influenced #history, and may threaten our future. Spoiler: it's really not a good idea to cut science at NASA. theconversation.com/solar-storms...
Ripples on the Cosmic Ocean is "one of the most fascinating histories of space exploration we know," according to Nautilus, because it shows how "space exploration doesn’t distract us from urgent Earthy issues; it helps us solve threats to Earth." #EnvHist nautil.us/the-nautilus...
The Nautilus Winter Reading List 2025
The Nautilus Winter Reading List 2025: Ten books we loved to start your new year off right.
nautil.us
December 22, 2025 at 4:51 PM
Ripples on the Cosmic Ocean is "one of the most fascinating histories of space exploration we know," according to Nautilus, because it shows how "space exploration doesn’t distract us from urgent Earthy issues; it helps us solve threats to Earth." #EnvHist nautil.us/the-nautilus...
Reposted by Dagomar Degroot
📣 New estimates shed light on late-18th century temperatures!
🕰️🌡️🌎 New research provides the first global record from near-surface air temperature measurements, peering back in time to the late-18th century.
Read more about it here: brnw.ch/21wYn3Z
🕰️🌡️🌎 New research provides the first global record from near-surface air temperature measurements, peering back in time to the late-18th century.
Read more about it here: brnw.ch/21wYn3Z
Climate Lab Book
Discussions on various aspects of climate science. Click to read Climate Lab Book, by Ed Hawkins, a Substack publication.
brnw.ch
December 15, 2025 at 3:51 PM
📣 New estimates shed light on late-18th century temperatures!
🕰️🌡️🌎 New research provides the first global record from near-surface air temperature measurements, peering back in time to the late-18th century.
Read more about it here: brnw.ch/21wYn3Z
🕰️🌡️🌎 New research provides the first global record from near-surface air temperature measurements, peering back in time to the late-18th century.
Read more about it here: brnw.ch/21wYn3Z
Reposted by Dagomar Degroot
This weekend is the 10th anniversary of the Paris Agreement. I wrote about the biggest change to global climate politics since its passage: The climate story *is* the China story now, and how countries pursue decarbonization is itself a wager on China’s future. heatmap.news/climate/pari...
10 Years After Paris, China Is Shaping Our Climate Future
The seminal global climate agreement changed the world, just not in the way we thought it would.
heatmap.news
December 13, 2025 at 4:08 PM
This weekend is the 10th anniversary of the Paris Agreement. I wrote about the biggest change to global climate politics since its passage: The climate story *is* the China story now, and how countries pursue decarbonization is itself a wager on China’s future. heatmap.news/climate/pari...
In "Ripples on the Cosmic Ocean," I chronicle how early efforts to defend against #asteroid and #comet impacts broke down over a simple question: should we focus on asteroids big enough to alter Earth's climate, or should we care about smaller city-killers, too? Today, we can do both! #EnvHist
NEW: When she worked at NASA’s JPL, Amy Mainzer used to rack up high scores on the 1979 Atari game ASTEROIDS. Very apt, now she’s in charge of a space mission that will save the world from killer asteroids.
Planet Protector, my new feature for @science.org, is live. www.science.org/content/arti...
Planet Protector, my new feature for @science.org, is live. www.science.org/content/arti...
NASA telescope will hunt down ‘city killer’ asteroids
With an infrared eye, NEO Surveyor will target dangerous space rocks glowing in the dark
www.science.org
December 12, 2025 at 3:12 PM
Ripples on the Cosmic Ocean, "a fascinating tour of the environmental history of the inner solar system," is a @sciam.bsky.social favorite book of the year. Check out the other books (both nonfiction and fiction) on the list! #Space #EnvHist #History www.scientificamerican.com/article/the-...
The Scientific American Staff’s Favorite Books of 2025
Here are the 67 books Scientific American staffers couldn’t put down this year, from fantasy epics to gripping nonfiction
www.scientificamerican.com
December 4, 2025 at 4:48 PM
Ripples on the Cosmic Ocean, "a fascinating tour of the environmental history of the inner solar system," is a @sciam.bsky.social favorite book of the year. Check out the other books (both nonfiction and fiction) on the list! #Space #EnvHist #History www.scientificamerican.com/article/the-...
Reposted by Dagomar Degroot
🔭 The new @esa.int budget secured today is a big deal imho. +30% compared to the current budget with largest chunk going to space transportation ie 🚀. Science/astro is also getting a big bump, which DG Aschbacher called ”the backbone of the ESA programme”. Some funding optimism to close off 2025! 💫🥹
22.1 billion euros subscribed.
A record.
A first.
And a clear message that Europe is serious about space and that @esa.int is the agency it trusts to deliver.
A historic Ministerial. A united Europe. A stronger ESA.
www.esa.int/About_Us/Cor...
A record.
A first.
And a clear message that Europe is serious about space and that @esa.int is the agency it trusts to deliver.
A historic Ministerial. A united Europe. A stronger ESA.
www.esa.int/About_Us/Cor...
ESA Member States commit to largest contributions at Ministerial
The largest contributions in the history of the European Space Agency, €22.1 bn, have been approved at its Council meeting at Ministerial level in Bremen, ...
www.esa.int
November 27, 2025 at 7:06 PM
🔭 The new @esa.int budget secured today is a big deal imho. +30% compared to the current budget with largest chunk going to space transportation ie 🚀. Science/astro is also getting a big bump, which DG Aschbacher called ”the backbone of the ESA programme”. Some funding optimism to close off 2025! 💫🥹
I've now written ten articles for @nichecanada.bsky.social, and I've long worked with environmental historian/cartographer extraordinaire @geoffmakesmaps.bsky.social, so this is special to me. A beautiful representation of 20+ years of increasingly global #EnvHist.
Today our editor, @micaamy.bsky.social, unveils a map made by Geoffrey Wallace that visualizes the geography of NiCHE blog posts going back to 2004.
"Animating the Archive: The Geography of NiCHE Posts since 2004"
niche-canada.org/2025/11/27/a...
#envhist #envhum #cdnhist #histgeog
"Animating the Archive: The Geography of NiCHE Posts since 2004"
niche-canada.org/2025/11/27/a...
#envhist #envhum #cdnhist #histgeog
Animating the Archive: The Geography of NiCHE Posts since 2004
While NiCHE began as a Canadian environmental history network, its subject matter has always been situated in an international context, fostering conversations and collaborations across borders.
niche-canada.org
November 27, 2025 at 7:31 PM
I've now written ten articles for @nichecanada.bsky.social, and I've long worked with environmental historian/cartographer extraordinaire @geoffmakesmaps.bsky.social, so this is special to me. A beautiful representation of 20+ years of increasingly global #EnvHist.
Mira Sha is a high school junior - and an emerging leader in #ClimateChange communication. She recently interviewed me for her podcast, "Signs of Change." And check out her other short interviews - she's got more than 40! open.spotify.com/episode/1d79...
#40 - Dr. Dagomar Degroot (GT)
open.spotify.com
November 24, 2025 at 3:51 PM
Mira Sha is a high school junior - and an emerging leader in #ClimateChange communication. She recently interviewed me for her podcast, "Signs of Change." And check out her other short interviews - she's got more than 40! open.spotify.com/episode/1d79...
Reposted by Dagomar Degroot
3 years ago, NASA crashed the DART spacecraft into an asteroid at 22,000 kilometers per hour. The event changed the asteroid's orbit and tilt & sent it tumbling.
A nearby cubesat captured these remarkable images of the asteroid immediately after the impact. 🧪🔭
aasnova.org/2025/11/03/s...
A nearby cubesat captured these remarkable images of the asteroid immediately after the impact. 🧪🔭
aasnova.org/2025/11/03/s...
November 19, 2025 at 4:12 AM
3 years ago, NASA crashed the DART spacecraft into an asteroid at 22,000 kilometers per hour. The event changed the asteroid's orbit and tilt & sent it tumbling.
A nearby cubesat captured these remarkable images of the asteroid immediately after the impact. 🧪🔭
aasnova.org/2025/11/03/s...
A nearby cubesat captured these remarkable images of the asteroid immediately after the impact. 🧪🔭
aasnova.org/2025/11/03/s...
How do you teach when the world could be ending? In this new article, I show how, in the 1960s, an MIT course provided a possible answer. Students were tasked with stopping an inbound asteroid - and worked out the principles of planetary defense. #EnvHist www.nationalgeographic.com/history/arti...
The students who developed a plan to stop Armageddon
In the 1960s, when the possibility of an asteroid impact alarmed the American public for the first time, MIT students drafted a blueprint for saving the Earth.
www.nationalgeographic.com
November 18, 2025 at 4:48 PM
How do you teach when the world could be ending? In this new article, I show how, in the 1960s, an MIT course provided a possible answer. Students were tasked with stopping an inbound asteroid - and worked out the principles of planetary defense. #EnvHist www.nationalgeographic.com/history/arti...
Reposted by Dagomar Degroot
I got it... I actually got it... Interstellar comet 3i, imaged from the middle of light-polluted Kendal, at 6am this morning, using my Seestar S50... This comet was already billions of years old before our Sun was even *born*... Very chuffed with this!
November 16, 2025 at 8:14 AM
I got it... I actually got it... Interstellar comet 3i, imaged from the middle of light-polluted Kendal, at 6am this morning, using my Seestar S50... This comet was already billions of years old before our Sun was even *born*... Very chuffed with this!
Reposted by Dagomar Degroot
My new book will be out in early December 2025 via
@mitpress.bsky.social
Details at: mitpress.mit.edu/978026255348...
#HistSci #Computing #History #Books 🗃️
@mitpress.bsky.social
Details at: mitpress.mit.edu/978026255348...
#HistSci #Computing #History #Books 🗃️
November 9, 2025 at 1:31 PM
My new book will be out in early December 2025 via
@mitpress.bsky.social
Details at: mitpress.mit.edu/978026255348...
#HistSci #Computing #History #Books 🗃️
@mitpress.bsky.social
Details at: mitpress.mit.edu/978026255348...
#HistSci #Computing #History #Books 🗃️
Reposted by Dagomar Degroot
This is lunacy. The Chinese scholars I know are among the hardest working, most selfless people I've ever encountered. They want to contribute to our intellectual endeavors, and they make our research teams better.
U.S. Congress considers sweeping ban on Chinese collaborations
Researchers speak out against proposal that would bar funding for U.S. scientists working with Chinese partners or training Chinese students
www.science.org
November 14, 2025 at 1:04 PM
This is lunacy. The Chinese scholars I know are among the hardest working, most selfless people I've ever encountered. They want to contribute to our intellectual endeavors, and they make our research teams better.
Reposted by Dagomar Degroot
Book swap with Professor @dagomardegroot.bsky.social, whose new book “Ripples on the Cosmic Ocean” tells the story of how environmental change throughout the cosmos has shaped human civilization 💫📖
November 14, 2025 at 3:11 AM
Book swap with Professor @dagomardegroot.bsky.social, whose new book “Ripples on the Cosmic Ocean” tells the story of how environmental change throughout the cosmos has shaped human civilization 💫📖
Great to join @miquai.bsky.social and the folks at @carnegiescience.bsky.social this morning to talk about Ripples on the Cosmic Ocean and, among other things, the existential risk of #SolarStorms. Check out Mike’s forthcoming book - an argument for a new force of nature! #Space
November 13, 2025 at 7:44 PM
Great to join @miquai.bsky.social and the folks at @carnegiescience.bsky.social this morning to talk about Ripples on the Cosmic Ocean and, among other things, the existential risk of #SolarStorms. Check out Mike’s forthcoming book - an argument for a new force of nature! #Space
Reposted by Dagomar Degroot
Exciting news! Student applications for paleoCAMP 2026 are open! Are you a graduate student working on any aspect of past climates or environments? Apply to be part of our 2-week summer school in the eastern Sierra Nevada! More details here: paleoclimate.camp/apply
Application — paleoCAMP
paleoclimate.camp
November 13, 2025 at 2:41 PM
Exciting news! Student applications for paleoCAMP 2026 are open! Are you a graduate student working on any aspect of past climates or environments? Apply to be part of our 2-week summer school in the eastern Sierra Nevada! More details here: paleoclimate.camp/apply
Reposted by Dagomar Degroot
SETI Institute communications specialist @planetarypan.bsky.social welcomed @dagomardegroot.bsky.social, environmental historian at Georgetown University, for a discussion on his new book Ripples on the Cosmic Ocean, released October 28, 2025. 🧪 👩🔬 📖
November 12, 2025 at 8:00 PM
SETI Institute communications specialist @planetarypan.bsky.social welcomed @dagomardegroot.bsky.social, environmental historian at Georgetown University, for a discussion on his new book Ripples on the Cosmic Ocean, released October 28, 2025. 🧪 👩🔬 📖
The worst thing about this is that an interstellar comet older than our solar system is mind-bogglingly fascinating, and all the bad faith speculation about aliens just wrecks an opportunity to engage the public with great science. #3IAtlas sites.psu.edu/astrowright/...
Loeb’s 3I/ATLAS “Anomalies” Explained
Avi Loeb continues to claim that 3I/ATLAS has many anomalous behaviors that lead to the conclusion that it “might” be an alien spacecraft. He carefully hedges the probability that it is a spacecraft ...
sites.psu.edu
November 12, 2025 at 4:29 PM
The worst thing about this is that an interstellar comet older than our solar system is mind-bogglingly fascinating, and all the bad faith speculation about aliens just wrecks an opportunity to engage the public with great science. #3IAtlas sites.psu.edu/astrowright/...
Reposted by Dagomar Degroot
Last week, @dagomardegroot.bsky.social joined @alimacewen.bsky.social on the Land and Climate Podcast, where he outlined climate shifts throughout history - from the Pleistocene through the Little Ice Age to the current Anthropocene - and their impacts on human civilisation.
Click below to listen!
Click below to listen!
This week, @alimac.bsky.social talks with @dagomardegroot.bsky.social about his new book, “Ripples on the Cosmic Ocean,” they discuss how the solar system has shaped human history and how humanity is now reshaping space.
@penguinrandomhouse.bsky.social
www.landclimate.org/...
@penguinrandomhouse.bsky.social
www.landclimate.org/...
November 10, 2025 at 1:47 PM
Last week, @dagomardegroot.bsky.social joined @alimacewen.bsky.social on the Land and Climate Podcast, where he outlined climate shifts throughout history - from the Pleistocene through the Little Ice Age to the current Anthropocene - and their impacts on human civilisation.
Click below to listen!
Click below to listen!
Reposted by Dagomar Degroot
Okay, here are some first reflections on Watson.
Watson's life is a tragedy, really of Shakespearean proportions. He did not, as most bios will tell you, do one great thing when he was young and then collect laurels for it for the next 60 years. His career arc was unlike any in science.
Watson's life is a tragedy, really of Shakespearean proportions. He did not, as most bios will tell you, do one great thing when he was young and then collect laurels for it for the next 60 years. His career arc was unlike any in science.
November 8, 2025 at 11:22 PM
Okay, here are some first reflections on Watson.
Watson's life is a tragedy, really of Shakespearean proportions. He did not, as most bios will tell you, do one great thing when he was young and then collect laurels for it for the next 60 years. His career arc was unlike any in science.
Watson's life is a tragedy, really of Shakespearean proportions. He did not, as most bios will tell you, do one great thing when he was young and then collect laurels for it for the next 60 years. His career arc was unlike any in science.
I love publishing with @aeon.co. In this article, come for the UAPs (!), stay for the Martian canal-builders - and the history of how they changed our ideas about the environment, our future, and our place in the universe. #EnvHist #Aliens #Mars #History aeon.co/essays/in-th...
In the late 1800s alien ‘engineers’ altered our world forever | Aeon Essays
Images of vast ‘canals’ rippling across the red planet inspired fears of alien ‘engineers’ and changed science forever
aeon.co
November 4, 2025 at 1:54 PM
Reposted by Dagomar Degroot
Your daily dose of climate hope. From the team at RMI: rmi.org/wp-content/u...
November 3, 2025 at 11:36 PM
Your daily dose of climate hope. From the team at RMI: rmi.org/wp-content/u...
What do you do when you see - or think you see - a change in a cosmic environment? I experienced that firsthand one strange night on a rooftop in Washington, DC. Here's my fourth video that introduces my new book, "Ripples on the Cosmic Ocean." #Moon #Astronomy #EnvHist youtu.be/kqCrSyPc8sY
Ripples on the Cosmic Ocean: A Spot on the Moon
YouTube video by Dagomar Degroot
youtu.be
November 3, 2025 at 5:05 PM
What do you do when you see - or think you see - a change in a cosmic environment? I experienced that firsthand one strange night on a rooftop in Washington, DC. Here's my fourth video that introduces my new book, "Ripples on the Cosmic Ocean." #Moon #Astronomy #EnvHist youtu.be/kqCrSyPc8sY
Reposted by Dagomar Degroot
#ICYMI: Environmental historian Dagomar Degroot explains that we can solve a climate issue if we work together... we have done it before! Watch the full #SETILive interview: youtube.com/live/iw7Irsc... 🧪 #podcast #climatechange
November 1, 2025 at 9:01 PM
#ICYMI: Environmental historian Dagomar Degroot explains that we can solve a climate issue if we work together... we have done it before! Watch the full #SETILive interview: youtube.com/live/iw7Irsc... 🧪 #podcast #climatechange
Reposted by Dagomar Degroot
An interstellar comet is such a cool find. It’s really a shame the bright nucleus of this wondrous appearance has been surrounded by an obscuring coma of alien conspiracy.
The Harvard astronomer responsible for that is doing sizable harm to the fields of speculative science he claims to represent.🧪
The Harvard astronomer responsible for that is doing sizable harm to the fields of speculative science he claims to represent.🧪
3I/ATLAS is behaving just as a comet should. No shenanigans. Looking forward to the possibility of JUICE (a European spacecraft heading eventually to Jupiter) observing this object in the coming weeks!
I have just received from Kevin Walsh of SWRI a re-analysis of the PUNCH data for 3I/ATLAS, & have redone our gas and dust coma prediction models as a result. These new data agree well with the independent reductions of Thomas Lehmann and bode well for the Juice observations starting November 2nd.
October 31, 2025 at 4:02 PM
An interstellar comet is such a cool find. It’s really a shame the bright nucleus of this wondrous appearance has been surrounded by an obscuring coma of alien conspiracy.
The Harvard astronomer responsible for that is doing sizable harm to the fields of speculative science he claims to represent.🧪
The Harvard astronomer responsible for that is doing sizable harm to the fields of speculative science he claims to represent.🧪