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Flavio Lehner

@climateflavors.bsky.social
2.2K followers 487 following 228 posts

Climate Scientist Assistant Professor @ Cornell University Chief Climate Scientist @ Polar Bears International flaviolehner.eas.cornell.edu

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Flavio Lehner @climateflavors.bsky.social · 11/10/2026
Thanks!
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Flavio Lehner @climateflavors.bsky.social · 09/10/2026
I feel like I recently saw a post that showed how the media still reports on extreme weather events but that a shrinking fraction of articles make a link to climate change. Did I dream this or does someone have that link/data?
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Daniel Swain @weatherwest.bsky.social · 30/09/2026
Wading into the "relative versus absolute" El Niño intensity debate: I genuinely think both are important--and I think we lose important information if we focus solely on one vs another. And both, as of late Sep, have now reached or exceeded record levels! [Thread]
Plot by Daniel Swain showing temporal evolution of ONI vs RONI index during 2026, representing two different ways to visualize El Nino intensity. The ONI has been at record levels since May, and the RONI has been at near-record levels since June. Data directly from NOAA.
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Kelly Hereid @kellyhereid.bsky.social · 22/09/2026
Also, if you want to follow climate people, quite a few of these folks are on bsky I'm sure I won't catch them all, but in addition to @bobkopp.net @costasamaras.com I see @sidersadapts.bsky.social @bistline.bsky.social @johncallahan.bsky.social @jmijin.bsky.social @jessemkeenan.com ... 1/2
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Bob Kopp @bobkopp.net · 22/09/2026
NEW PAPER: In a new paper, jointly published in @agu.org Earth's Future & @ametsoc.org BAMS, and co-led by Melissa Kenney, @costasamaras.com and me, 175 authors outline priorities to guide the future of scientific assessments of climate change in the United States. 🧵
doi.org
Research Priorities for Robust Climate Assessments in the United States
A network of climate assessments plays a critical role in synthesizing the state of science to support evidence-based decision-making To support future U.S. and sub-national climate assessments, ...
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Climate.us @climate.us · 09/09/2026
Sea Ice Today is back! For nearly two decades, scientists at the National Snow and Ice Data Center, or NSIDC, have helped people understand what is happening to sea ice in the Arctic and around Antarctica. Its monthly science analyses were paused last fall. buff.ly/e20zCU6
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Flavio Lehner @climateflavors.bsky.social · 05/09/2026
Mostly clouds. agupubs.onlinelibrary.wiley.com/doi/abs/10.1...
agupubs.onlinelibrary.wiley.com
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Zack Labe @zacklabe.com · 05/09/2026
The second edition of Canada’s Changing Climate Report (CCCR2026) is now published, which discusses past and future climate change for the region, as well as Indigenous science and perspectives. Canada is warming at twice the global rate. Learn more at www.canada.ca/en/environme...
Graphic showing future climate-related changes in Canada would be much larger under current or weaker policies than in a net-zero future, which is from chapter 3 at https://www.canada.ca/en/environment-climate-change/services/science-technology/changing-climate-report-2026/cccr-chapter-3-en.html.
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Flavio Lehner @climateflavors.bsky.social · 03/09/2026
Right!
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Flavio Lehner @climateflavors.bsky.social · 03/09/2026
Yes, and thanks to emission-driven runs in CMIP7, model uncertainty will likely grow in a relative *and* absolute sense. It'll also be interesting to compare with some (controversial) constraints on scenario uncertainty published in recent years. agupubs.onlinelibrary.wiley.com/doi/abs/10.1...
agupubs.onlinelibrary.wiley.com
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Flavio Lehner @climateflavors.bsky.social · 02/09/2026
Right, the paper makes it sound a bit like they just discovered that some ensemble members can sort of get it and that earlier periods had opposite trends, and thus internal variability has a role to play. But (hopefully) nobody ever said internal variability has no role.
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Flavio Lehner @climateflavors.bsky.social · 02/09/2026
I only just discovered this fun thread: bsky.app/profile/thir...
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Flavio Lehner @climateflavors.bsky.social · 02/09/2026
New paper on Pacific SST trends, reverting back to ~'this is mostly internal variability, the models are probably fine'. However, I struggled a bit to understand what is new about the line of argument. Thoughts? @robbjnglinwills.bsky.social @cristiproist.bsky.social www.pnas.org/doi/abs/10.1...
pnas.org
Major role for internal variability in tropical Pacific warming pattern over satellite era | PNAS
Home to El Niño, the tropical Pacific is a key player in the global climate system. While most of the planet has warmed during the satellite era of...
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Flavio Lehner @climateflavors.bsky.social · 01/09/2026
Definition of grunt work. Tedious and seemingly unglamorous but very important and useful. Upshot: some of the observed recent drying in arid regions was overestimated, but not enough to fully explain the discrepancy between models and reality. agupubs.onlinelibrary.wiley.com/doi/full/10....
agupubs.onlinelibrary.wiley.com
Identifying and Correcting Inhomogeneities in the Near‐Surface Specific Humidity Record
Changepoint detection is applied to ERA5 and HadISDH humidity data with a circulation-constrained climate model simulation as the reference Changepoints are identified across 31% of global land a...
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Flavio Lehner @climateflavors.bsky.social · 26/08/2026
No.
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Flavio Lehner @climateflavors.bsky.social · 26/08/2026
Users should be made aware of what the science says, sure. But if it’s “widely understood”, it should emerge from the science, not top down from an administration.
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Flavio Lehner @climateflavors.bsky.social · 25/08/2026
NCA isn't the place to make that correction (even if you believe it's necessary). Science assesses what-if scenarios and doesn't steer policy. Also, if they wanted this to be science-based, they could have let us take a stab at it in NCA6. Lots of papers since NCA5 on scenario plausibility!
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Flavio Lehner @climateflavors.bsky.social · 25/08/2026
Wait, is this @vsrikrish.bsky.social ?
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Flavio Lehner @climateflavors.bsky.social · 25/08/2026
"...results dependent on these pathways should not be presented as expected [...] or ordinary Federal planning futures unless the same result is independently reproduced under a presently plausible scenario and evaluated against observations." Evaluating a future scenario against observations?!
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Minas Karamanis @minaskar.bsky.social · 30/03/2026
Hey, I wrote a thing about AI in astrophysics ergosphere.blog/posts/the-ma...
ergosphere.blog
The machines are fine. I'm worried about us.
On AI agents, grunt work, and the part of science that isn't replaceable.
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Flavio Lehner @climateflavors.bsky.social · 21/08/2026
Indeed, this summer didn't come as a surprise to most climate scientists, but it nonetheless leaves an eerie feeling to see once outlandish events become "normal".
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Robert Rohde @rarohde.bsky.social · 14/08/2026
With record-breaking heatwaves, France just had both its warmest June and July on record. Systematic collection of weather data basically began in Western Europe, giving Europe the longest thermometer-based histories in the world. After more than 250 years, we have changed the climate. 🧪
Time series graph of June-July average temperature in France relative to the 1850-1900 baseline.  Data from Berkeley Earth.
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Daniel Swain @weatherwest.bsky.social · 14/08/2026
I've been talking a lot about the disastrous recent loss of American institutional capacity regarding climate science. But today, I'd like to announce something we've been working on, quietly, in the meantime to offer a lifeline to some of those affected. [Thread]
First page of a 2-page flyer describing the Climate Science and Communications Fund. It shows a map of gift recipient locations, and also summarize statistics regarding the program thus far (including over $3 million disbursed to date), with testimonials from individual recipients.Second page of a 2-page flyer describing the Climate Science and Communications Fund. It further describes the need for and goals of the program. It also includes a point of contact email: roshan@climate-talent.org
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Gernot Wagner @gwagner.com · 05/08/2026
"Heat kills — both lives and livelihoods." "And it is often rather small changes in the average that lead to large threshold effects" @chinadailyusa.bsky.social gwagner.com/china-daily-heat "only one additional day above 32 C in any given year lowers annual payroll by 0.04 percent" gwagner.com/hle
China Daily: "Is El Nino's economic risk too hot to handle?"
by Yang Gao
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Project Drawdown @projectdrawdown.bsky.social · 31/07/2026
🚨 Scientists have been warning for more than a century that catastrophic weather events were inevitable if humanity kept emitting GHG's. But is it worse than even they expected? Climate scientist @drkatemarvel.bsky.social shares her expert perspective in our latest Insights: bit.ly/4wsYPMw
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John Fasullo @jfasullo.bsky.social · 12/07/2026
Objective measures of @NCAR_CGD climate science show it to be at the forefront of scientific discovery www.dailycamera.com/2026/07/11/n...
dailycamera.com
Amid the administration’s attacks on climate change, NCAR and CU Boulder rank top 10 in the world for climate research
NCAR earned second place globally out of more than 40,000 institutions, with Carbon Brief noting it had some of the most highly cited authors.
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Robert Koch-Institut @rki.de · 09/07/2026
🌡️ Wie hat sich die Hitzewelle in der Kalenderwoche 26 auf die Sterblichkeit in Deutschland ausgewirkt? Zur Schätzung der hitzebedingten Sterbefälle erstellt das RKI eine Modellierung, die Daten vom Statistischen Bundesamt und @dwdderwetterdienst.bsky.social kombiniert. ➡️ www.rki.de/hitzemortali...
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IPCC @ipcc.bsky.social · 06/07/2026
📣 IPCC opens registration for experts to review the First Order Draft of Working Group I contribution to Seventh Assessment Report. The review runs from 10 August until 2 October. Interested experts can register until 25 Sept 2026: bit.ly/4vi25cq Read more 🔗 bit.ly/WGI7Fod
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Gernot Wagner @gwagner.com · 01/07/2026
Pay peer reviewers $290 per submission, see review times go down from 38 days (with a long upper tail) to 5.5 days (with v. few 'late' reviews), and watch quality go up to boot. Who knew? #IncentivesIncentivize www.nature.com/articles/d41...
Paying peer reviewers speeds up editorial decision time
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Flavio Lehner @climateflavors.bsky.social · 28/06/2026
I don’t think there’s much evidence. erikwkolstad.com/2026/05/12/u...
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Maddie Stone @themadstone.bsky.social · 25/06/2026
I’ve spent more than a year reporting on how the fossil fuel industry has infiltrated academia over the last 30 years, shaping fundamental paradigms on how to address climate change. My first story in the new @propublica.org and @drilledmedia.bsky.social series, “Carbon Captured”, is out today.
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Flavio Lehner @climateflavors.bsky.social · 23/06/2026
I think there’s also good papers on heat extremes by karen mckinnon and kai kornhuber. Precip is a bit harder due to signal to noise but i think angie pendergrass has something in review that gets at the pace of extreme precip distribution shifts.
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Flavio Lehner @climateflavors.bsky.social · 23/06/2026
The paper kevin linked indirectly argues that this kind of analysis should henceforth more often accompany any case studies. Made similar arguments here: www.sciencedirect.com/science/arti...
sciencedirect.com
Climate model large ensembles as test beds for applied compound event research
Some of the most impactful climate and weather events result from compounding drivers. To robustly assess the current and future risk from such compou…
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Ed Hawkins @edhawkins.org · 22/06/2026
The UK summer of 1976 was an extraordinary heatwave for its time. On the 50th anniversary, we look back to learn about what that event can tell us today. For those who experienced the heatwave it is engrained in the memory, but it gives us a stark warning about future extreme heat for the UK.
Heatwave 1976-2026. Our memory. Their future.
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aederocher.bsky.social @aederocher.bsky.social · 21/06/2026
As Hudson Bay sea ice melts, the bears are moving onshore. This is a bit early than optimal but depends on the condition of the bears & how long until freeze-up in autumn. Bears were lean in April-May when I was out sampling in the spring but a lot can change later in spring (most critical time).
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Flavio Lehner @climateflavors.bsky.social · 19/06/2026
Nice! Just watched it. Sounds great. I can shoot you an email.
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Flavio Lehner @climateflavors.bsky.social · 18/06/2026
(ignore the tropics due to their weak annual cycle) There's probably nothing here but it's fun to think about in light of some research on that particular heatwave, like the new paper by Gary Lackmann: doi.org/10.1175/MWR-...
doi.org
The Role of an Atmospheric River in Amplifying the June 2021 Western North American Heat Wave
Abstract In this study, we explore the role of upstream processes associated with the western North American heat wave of late June 2021. Upstream latent heat release associated with an atmospheric ri...
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Flavio Lehner @climateflavors.bsky.social · 18/06/2026
What is the probability (and physical mechanisms) of having your local record temperature occur earlier or later than the climatologically hottest time of year? E.g., the 2021 PNW heatwave occurred >1 month before the hottest time of year. Anyone know a study? Figure based on ERA5 1940-2025.
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Zack Labe @zacklabe.com · 13/06/2026
El Niño is here, which means it's time for me to dust off and refine my old collection of ENSO-related climate visualizations. Check out how much sea surface temperatures have already warmed this year across the equatorial tropical Pacific. Wow! Data from psl.noaa.gov/data/gridded...
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Amy McGovern @profamymcgovern.bsky.social · 12/06/2026
NY times covered our cut today (gift article) www.nytimes.com/2026/06/12/s...
nytimes.com
She Used A.I. to Improve Forecasts for Extreme Weather
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Flavio Lehner @climateflavors.bsky.social · 12/06/2026
Another doping example that is well know is cycling.
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Flavio Lehner @climateflavors.bsky.social · 12/06/2026
I've actually used this example in class (where I'm also using your text book) and also in talks and it works well - but this is at a US university. I'd sub jargon like "fly ball" or "at-bat" with plain english. "Home run" and maybe "base" are the only words I've heard of before coming to the US.
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Katharine Hayhoe @katharinehayhoe.com · 09/06/2026
Context: in 2018, FB labeled clean energy & climate as “political” topics. I was told I had to “register as a political entity.” I’m a scientist, I said. Over my dead body. So my previously thriving page was shadowbanned-til Dec when the algo was altered to deliberately promote divisive content 😳
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Dr. Jeff Masters @drjeffmasters.bsky.social · 08/06/2026
May 2026 had the second-worst May drought conditions in contiguous U.S. history, with a Palmer Drought Severity Index (PDSI) of -6.93. The only worse May: the Dust Bowl year of 1934 (a PDSI of -7.03). Three of the top-10 months for worst U.S. drought since 1895 have been in 2026:
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Kevin Schwarzwald @kschwarzwald.bsky.social · 06/06/2026
Ein problem für ganz Europa, und wo die USA ausnahmsweise auch voraus liegt (durch ua die flächendeckende Klimaanlagenaustattung ist die Anzahl der Hitzetote generell viel niedriger, auch bei ähnlichen und teils viel schlimmeren Hitzeperioden!) (zB hannahritchie.substack.com/p/heat-guns-... )
hannahritchie.substack.com
Do more Europeans die of summer heat than Americans die of guns?
An attempt to improve a viral chart.
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Andrew Williams @andrewilwilliams.bsky.social · 05/06/2026
Thank you for joining us and speaking out in support of weather & climate science, @repericsorensen.bsky.social ! @wclivestream.bsky.social
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The Weather & Climate Livestream @wclivestream.bsky.social · 04/06/2026
That's a wrap! - 50 hours of science + calling Congress - 300 letters given to Congress after a 250-mile walk We provided the templates and our viewers and supporters injected their voices. And like last year, we feel so uplifted by our community. Thank you for spending your time with us
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Flavio Lehner @climateflavors.bsky.social · 03/06/2026
Thanks Jeff! Emphasis on "may". Lots of competing (and complementary) theories out there on which forcing will win out. I did make a bet with another professor re snow drought occurrence this decade. The looser will have to give a guest lecture explaining why they lost. :)
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Katharine Hayhoe @katharinehayhoe.com · 30/05/2026
I’m a climate scientist. Let me fix this headline. “Nearly a century ago, scientists showed that burning fossil fuels warms the planet. Today, we know human emissions account for over 100% of the warming. Yet dark money and disinformation still work to keep Americans addicted to fossil fuels.”
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