Joe MacGregor

NEW: Extraordinary footage has emerged of the huge tsunami that hit Russia’s remote Kamchatka peninsula after the 8.8 magnitude earthquake on July 30th.

(🎥 Doni Nikz)

🚨 Our new preprint!
*Cascading mass loss of Antarctic ice shelves triggered by iceberg collisions*

🔗 doi.org/10.22541/essoar.175285257.77669558/v1

In 2021, giant icebergs hit Dronning Maud Land ice shelves in #Antarctica, causing a chain reaction of calving & major regional ice-shelf area loss. 💥

Sentinel-2 reveals the surface deformation after the 2025 #Myanmar #earthquake www.cesbio.cnrs.fr/multitemp/se...

Please share with teens or anyone you know who work with teens! #girlsinstem #glaciology #sciart #womeninstem #science this program is for teens willing to challenge themselves (**not** for just top performing students - we are open, no need to be a science or art geek either, just willing to try)

Late Gen Xer so easily Hunger Strike

Well deserved!

Was that with Niels?

A new gigantic outburst flood from Catalina lake in East Greenland [Catalinadal, Renland, Scoresbysund].

total volume: 3.4 km3
peak discharge: ~7200 m3/s
top-10 #GLOF in terms of both numbers.
previous outburst 2013

I'm sending out a press release today about it.
🧪❄️ 🥼❄️
1/x

Snow4Flow logo

The Snow4Flow concept paper is out! See notice in cryolist from Thursday. This will form the basis for the later AO. Stickers at #AGU24. snow4flow.lpl.arizona.edu/concept-paper

In work I’ve been quietly doing, many dozens of people’s stories & early writing drafts, one thing’s increasingly clear.

“Safety by Exclusion”—the dominant paradigm in polar science & most geosci sub-fields—isn’t just harmful, it’s ineffective. It DOESN’T WORK! Makes everyone less safe, in fact. 🧪⚒️

🧪 Well-meaning arguments to “keep science apolitical” just cede the far-right-wing propaganda framing that science…

• “used to be apolitical”,
• “recently became politicized”, and ∴
• “needs to be fixed.”

Which is 100% bullshit on every single point.

Don’t do their propaganda for them.

In the podcast, MacGregor describes a new method of visualizing the surface of the ice sheet in which the simulated illumination of a digital elevation model varies according to the direction of surface ice flow. (A) Map of Greenland’s surface shaded using flow-aware hillshade, in which the artificial illumination direction (and corresponding shadows) at each pixel is 90 degrees counterclockwise to the ice-flow direction. The resulting shading emphasizes small-scale variability in the ice-sheet surface slope, which is primarily related to variability in the topography under the ice. The change in shading from the middle of the ice sheet to the periphery reflects the smaller slopes in the interior and the smaller surface bumps induced by subglacial topography, because as the ice thickness decreases, the surface becomes more sensitive to what is going on below. The map is based on the laser altimetry data. (B) The green lines are manual tracings of linear features in the map. GrIMP: Greenland Ice Mapping Project.

This is the new geological map of Greenland. It is based on the set of geophysical surveys whose results are summarized in the maps in the previous figure. The geological provinces are colored by age. Three newly identified provinces (unshaded Regions A, B, and C) do not correspond to known provinces of the exposed periphery of Greenland.

Listen to a new episode with @joemacgregor.bsky.social on mapping Greenland's geology below the ice. An impressive story of synthesizing decades of geophysical seismic, gravity, and magnetic surveys together with radar and laser altimetry. Newly discovered: long valley networks, 3 new provinces.

Ice-sheet runoff at Kangerlussuaq, Greenland

Cape York meteorite in Copenhagen

Ruth (red tri) and Mara (black tri) reconnecting

Byrd checking in on her domain

Lots of new people here so a reintroduction: Glaciologist & geophysicist. Big fan of ice, especially the grounded form, at both poles. Keen on radar sounding, airborne & satellite remote sensing, & developing better boundary conditions for ice flow models. Sometimes I meme, other times I exercise.

Yay ice!

Hi newskies - if you're interested in climate risk, and you don't follow @scrawford.bsky.social, you should probably fix that.

The first circular for the IGS Symposium on Ice Streams and Outlet Glaciers is out now! ❄️ We have some fantastic invited speakers lined up and are looking forward to welcoming you to Durham in July 2025. Check out the circular and register your interest here: www.igsoc.org/event/ice-st... ⚒️🧪

everyone—not just homebuyers, but banks, municipal bond investors, regulators—just want to be directed to that good dataset but it’s unfortunately a lot more complicated than that

Carbon capture and storage is designed to capture government subsidies, not carbon.

From crevasse falls to polar bears, train fieldwork leaders for emergencies Fieldwork can be deadly: heads of expeditions must be taught how to cope in a crisis.

Field scientists and those that approve expenses like wilderness first aid and crevasse rescue courses, READ THIS from @snowhydro.bsky.social: www.nature.com/articles/d41...

Unpriced climate risk and the potential consequences of overvaluation in US housing markets - Nature Climate Change Natural hazards exacerbated by climate change pose serious risks to property markets in the United States. Ignoring these risks could create instability in housing values. This research shows the magn...

keep thinking about my student last year from asheville who read that investors were buying up property there in expectation of it becoming a climate migration destination and she wrote her final paper about how that doesn't seem quite right given its flood risk history and maps like this one

Future increase in extreme El Niño supported by past glacial changes - Nature A combination of palaeoclimate proxies and simulations shows that a common mechanism controls El Niño variation in cold and warm states, which supports expectations of more extreme El Niño occurr...

Paleoclimate constraints on the future of El Niño: congrats to @carbon8.bsky.social and all the coauthors www.nature.com/articles/s41...

I highly recommend @scrawford.bsky.social's newsletter, which I think @kellyhereid.bsky.social clued me in to. Always informative and insightful into ongoing adaptation strategies and challenges associated with sea-level rise.

Home – U.S. Sea Level Change Access federally-supported data visualizations and resources on regional sea level changes and sea level rise in the U.S.

Check out a new multi-agency effort on sea level rise for the US. Updated observations and projections including vertical land motion impacts.

sealevel.globalchange.gov

‘Oh my God, what is that?’: how the maelstrom under Greenland’s glaciers could slow future sea level rise A pioneering mission into a mysterious and violent world may reveal ‘speed bumps’ on the way to global coastal inundation

www.theguardian.com/environment/...

Complex, Hidden Landscape Mapped a Mile under Greenland Ice A new Greenland map suggests how geology might shift and twist below the ice

Scientific American gave a brief intro of our new map of Greenland’s subglacial geology — “Complex, Hidden Landscape Mapped a Mile under Greenland Ice” — led by @joemacgregor.bsky.social

www.scientificamerican.com/article/comp...

Greenland fossil discovery stuns scientists and confirms that center of ice sheet melted in recent past The story of Greenland keeps getting greener—and scarier. A new study provides the first direct evidence that the center—not just the edges—of Greenland's ice sheet melted away in the recent geologica...

Greenland was warm enough, for long enough, for an entire tundra ecosystem where today ice is two miles deep, during an interglacial within the last million years 🧪⚒️❄️ phys.org/news/2024-08...

Data visualization of monthly temperatures over time. The X-axis shows months of the year and the Y-axis shows temperature in degrees Celsius, running from below 12 to above 17. A thick section of lines in white indicates data from the years 1980 to 2022. A pink line that rises above the white lines represents the year 2023. And crisscrossing but mostly above that is a red line representing 2024 through June, with the month of July marked in purple, rising above everything else, to above 17 degrees Celsius.

Oh hey, this is finally public!

I've been working for a bit with the GMAO folks at NASA GSFC to leverage the near-real-time capabilities of GEOS-FP in combination with the robustness + length of record of the MERRA-2 reanalysis.

Last week was hella hot, y'all!

www.nasa.gov/earth/nasa-d... 🧪⚒️

Hey All! We're looking for a glaciology PhD student at DTU-Space to model the ice flow of the Greenland ice sheet over the past 12,000 years. 👇

efzu.fa.em2.oraclecloud.com/hcmUI/Candid...

The CISP team is fun and growing! This call closes 16 August 2024.

Geologic Provinces Beneath the Greenland Ice Sheet Constrained by Geophysical Data Synthesis We produced a new synthesis of subglacial boundaries for Greenland's geologic provinces from seismic, gravity, magnetic and topography data Three subglacial regions in central and northern Greenl...

It's both. Mathieu will fix any obvious artifacts you report, but I doubt there's many left...typically due to top of disrupted basal ice being picked as the bed. More common are sparsely sampled subglacial valleys that show up as isolated holes. See: agupubs.onlinelibrary.wiley.com/doi/10.1029/...

Even a short break in the records can create problems. Say an ice shelf collapses in Greenland. Unless you were measuring sea-level rise before, during and after, you’ll never be sure a sudden change was caused by the collapse, said William B. Gail, a former president of the American Meteorological Society. “You might surmise it, but you don’t have a quantitative record,” he said.

This is poor/confusing framing for several reasons. Among them: We ARE measuring sea-levels now and have been for decades, and NOT with Terra/Aqua. It's painful to lose them, but for detecting ice-shelf collapse, there are other satellites with comparable ability.
www.nytimes.com/2024/05/03/c...