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Nick Lutsko

@nick-lutsko.bsky.social
162 followers 206 following 122 posts

Associate Professor of Climate Science at Scripps Institution of Oceanography/UCSD. More at: www.sio-climatephysics.com and notesonclimate.substack.com

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Nick Lutsko @nick-lutsko.bsky.social · 28/09/2026
Haha yes I just meant not starting from existing code
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Nick Lutsko @nick-lutsko.bsky.social · 28/09/2026
(Also a better analogy to the Navier Stokes result would be if an LLM wrote a better climate model from scratch)
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Nick Lutsko @nick-lutsko.bsky.social · 28/09/2026
…km-scale models and mesoscale organization. One benefit of ML is It allows for a broader range of model architectures, which will let us test different hypotheses for what drives model uncertainty
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Nick Lutsko @nick-lutsko.bsky.social · 28/09/2026
I agree that trust comes from verification, in the absence of which we need auditable steps, but the rest is somewhat one-sided (and unfair to end-to-end ML models). CliMA is set up to address one source of model uncertainty. Bjorn Stevens could write a similar essay about…
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Nick Lutsko @nick-lutsko.bsky.social · 13/09/2026
climate-analytics-lab.github.io/projects/jax...
climate-analytics-lab.github.io
JAX-GCM
A fully differentiable climate model for ML-enhanced climate science
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Nick Lutsko @nick-lutsko.bsky.social · 13/09/2026
I haven’t had a chance yet, but it’s an interesting idea. I think NVIDIA has a tool for running some of these models yourself? Otherwise you might like to try the Jax GCM we’ve been working on at Scripps. It’s like a smaller version of NeuralGCM you can run on a single GPU
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Nick Lutsko @nick-lutsko.bsky.social · 11/09/2026
PS if you're interested in ML and weather forecasting, Brightband's operational forecast leaderboard is an essential resource owb.brightband.com
owb.brightband.com
Operational WeatherBench | AI Weather Forecast Leaderboard
Live skill rankings for AI and physics-based weather forecast models, scored daily with standard metrics and an open toolkit.
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Nick Lutsko @nick-lutsko.bsky.social · 11/09/2026
Wrote a short post on why Google's WeatherNext forecasting models are so good. TLDR: it's probably not the architecture, but how they train their models (though there's an interesting analogy to singular vectors in what they're doing) notesonclimate.substack.com/p/why-are-go...
notesonclimate.substack.com
Why are Google’s WeatherNext Models So Good?
Going from architecture to training
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Reposted by Nick Lutsko
Casey Ivanovich @ccivanovich.bsky.social · 10/09/2026
Feel like heatwaves started early this year? Or like they're dragging on later than ever? Our new @aguadvances.bsky.social paper shows that extreme heat is no longer limited to summer and is now creeping into the shoulder seasons -- but unevenly so. (1/6) doi.org/10.1029/2026...
doi.org
Extreme Dry and Humid Heat Seasons Are Changing Asymmetrically
Extreme dry and humid heat events show distinct seasonality often not aligned with meteorological summer, even in the tropics Extreme heat seasons have expanded since the 1980s over about half of...
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Nick Lutsko @nick-lutsko.bsky.social · 02/09/2026
This is an interesting test case. The ML ensembles are much more confident in the W track than the physical ensembles, which are bimodal. Either they know something about the driving synoptic conditions, their perturbations aren’t sampling the bifurcation or they’re reverting to climatology
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Nick Lutsko @nick-lutsko.bsky.social · 31/08/2026
Wrote about the atmospheric physics behind the FAA's proposal to allow "boomless" supersonic flight. notesonclimate.substack.com/p/boomless-s... This is a cool idea, though I'm skeptical of it working in practice
notesonclimate.substack.com
“Boomless” Supersonic Flight and the Mach Cut-off
The speed of sound, Snell’s Law and the FAA
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Nick Lutsko @nick-lutsko.bsky.social · 30/08/2026
…a stationary wave (a monsoon!) Finally the shot at GCMs is a little unfair (they can simulate blocks even if imperfectly), but I guess he needs this to justify the “LHC for climate”
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Nick Lutsko @nick-lutsko.bsky.social · 30/08/2026
It’s great to see Tim in the economist, but this is a strange piece. He seems to say we aren’t sure whether dynamics will be affected by climate change, but the question is how not if. Writing “persistent anticyclone” rather than just calling it a block is also confusing, since this could refer to…
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Reposted by Nick Lutsko
Mike Byrne @drmichaelbyrne.bsky.social · 27/08/2026
Counterintuitively, mixing of dry air into convecting plumes amplifies moist heat extremes. This "entrainment" effect strengthens as climate warms and dries, increasing human heat stress. Details in our new paper, led by @roshanjha.bsky.social: agupubs.onlinelibrary.wiley.com/doi/10.1029/...
agupubs.onlinelibrary.wiley.com
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Nick Lutsko @nick-lutsko.bsky.social · 14/08/2026
…you might expect new hotspots to show up with desertification, but the models suggest temperature records will keep being set in the Middle East and eastern North Africa
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Nick Lutsko @nick-lutsko.bsky.social · 14/08/2026
Very much inspired by Mike’s work, Anthony showed the very hottest temperatures warm 30-40% faster than the tropical mean — we should start seeing global max temperature records broken pretty soon Interestingly, the locations of the warmest temperatures seems quite stable…
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Nick Lutsko @nick-lutsko.bsky.social · 12/08/2026
…tell us something interesting about the forced response
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Nick Lutsko @nick-lutsko.bsky.social · 12/08/2026
…which favor having the strongest warming in continental interiors (eg Central Asia), and more transient reasons for Europe’s recent warmth (circulation and aerosol changes) It‘s also possible the models underestimate land surface feedbacks or circulation changes over Europe, so recent trends…
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Nick Lutsko @nick-lutsko.bsky.social · 12/08/2026
I appreciate the effort to explain climate dynamics to a broad audience, but I find these explainers on Europe’s fast warming a little misleading. They tend to mix generic reasons why land warms faster than the global mean (land/ocean contrast, sea ice loss)…
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Nick Lutsko @nick-lutsko.bsky.social · 27/07/2026
and drives the negative feedback. This is consistent with what we know about cloud physics, and unlikely to continue unless you think the tropical Pacific gradient will keep strengthening
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Nick Lutsko @nick-lutsko.bsky.social · 27/07/2026
Putting the satellite data together is nice, the headline result is maybe less surprising than at first glance. The 2 main low cloud CCFs are SST (+ve fdbk)) and EIS (-ve fdbk). The weak historical EP warming means the SST contribution is relatively weak and the EIS contribution is relatively large…
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Reposted by Nick Lutsko
Kevin Anchukaitis @thirstygecko.bsky.social · 26/07/2026
High-resolution simulations reveal positive global warming feedback from Pacific low clouds www.science.org/doi/10.1126/...
science.org
High-resolution simulations reveal positive global warming feedback from Pacific low clouds
High-resolution simulations reveal that direct carbon dioxide effects nonlinearly amplify positive low-cloud feedbacks.
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Nick Lutsko @nick-lutsko.bsky.social · 24/07/2026
The 500hpa heights and surface pressures from the CPC
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Nick Lutsko @nick-lutsko.bsky.social · 24/07/2026
This is an interesting pattern. The surface temp anomalies look wave 4-ish, but a trapped k=4 wave is unlikely in NH summer (jet is too weak). The 500hPa heights and SLP are messier, so the temp pattern is probably a summer stationary wave pattern that was sharpened by surface feedbacks
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Nick Lutsko @nick-lutsko.bsky.social · 21/07/2026
See the end for a fun derivation of where the sqrt(CH4) scaling comes from
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Nick Lutsko @nick-lutsko.bsky.social · 21/07/2026
Following up on @zekehausfather.com post on early 20thC warming, I was surprised how large methane‘s contribution was. Turns out it was swamped after WW2 by faster CO2 emission growth even though CH4 forcing is stronger molecule-for-molecule notesonclimate.substack.com/p/methane-ma...
notesonclimate.substack.com
Methane Mattered More in the Early 20th Century
Zeke Hausfather had an interesting post recently at The Climate Brink on what drove early 20th Century warming, suggesting it was a roughly equal mix of human activity, natural forcings (volcanoes) an...
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Nick Lutsko @nick-lutsko.bsky.social · 10/07/2026
It’s interesting that methane was a relatively larger contributor to the early 20thC warming than more recent warming. I guess agriculture was a relatively larger share of emissions compared to fossil fuel burning?
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Nick Lutsko @nick-lutsko.bsky.social · 10/07/2026
Wrote about the ways people have implemented physical constraints in ML-driven weather forecast systems: notesonclimate.substack.com/p/physical-c... Physics still matters! But there are also a lot of open questions, and, as an outsider, I think this would benefit from a more systematic approach
notesonclimate.substack.com
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Nick Lutsko @nick-lutsko.bsky.social · 01/07/2026
So this is a cool idea, but might be difficult to achieve in practice. An alternative is to reduce the boom through the plane's design (as NASA's X-59 tries to do) rather than relying on the atmosphere
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Nick Lutsko @nick-lutsko.bsky.social · 01/07/2026
But flying just above the Mach speed is the most fuel-intensive way of flying due to something called transonic drag. It also relies on precise weather forecasting to get the speed right -- the tropopause is a dynamic place with folds, wave breaking, etc.
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Nick Lutsko @nick-lutsko.bsky.social · 01/07/2026
The problem is the maximum speed is set by c_surf, i.e., max v = \sqrt(T_surf) / \sqrt(T_trop). Setting T_surf = 300 and T_trop = 220, you get a maximum speed of ~1.17 x c_trop (or Mach number 1.17)
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Nick Lutsko @nick-lutsko.bsky.social · 01/07/2026
A plane flying just above the local speed of sound near the tropopause (c_trop) will emit a sonic boom, but Snell's Law tells us refraction bends the sound waves away from the vertical. Under the right conditions, they turn upward before reaching the ground. This is called the "Mach cut-off" ...
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Nick Lutsko @nick-lutsko.bsky.social · 01/07/2026
The speed of sound in the atmosphere (c) goes as sqrt(T), decreasing as you move up in the troposphere. The slowest speeds are at the tropopause (the coldest part of the atmosphere) ...
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Nick Lutsko @nick-lutsko.bsky.social · 01/07/2026
The WH has a new EO encouraging the FAA to allow supersonic flight over the US if the plane doesn't create a sonic boom that reaches the ground: www.faa.gov/newsroom/ARM... This actually relies on a fun bit of atmospheric physics, which also shows why this might not be a great idea in practice 🧵
faa.gov
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Nick Lutsko @nick-lutsko.bsky.social · 01/07/2026
Definitely plausible that it played a role, but it’s probably one factor in a larger trend
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Nick Lutsko @nick-lutsko.bsky.social · 01/07/2026
One quick check is looking at how the ENSO forecasts evolved. There’s a shift toward El Niño between March and April, but to me it looks more like a smooth progression than a jump in April iri.columbia.edu/our-expertis...
iri.columbia.edu
IRI – International Research Institute for Climate and Society | April 2026 Quick Look
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Nick Lutsko @nick-lutsko.bsky.social · 26/06/2026
Don’t forget about FiTT, which was coined by the group that runs the DAM convection model
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Nick Lutsko @nick-lutsko.bsky.social · 24/06/2026
Wrote a summary of Yue Xu‘s recent surface forcing paper notesonclimate.substack.com/p/a-spectral... Our simple model can be combined with similar TOA models to understand the atmospheric forcing, which has some interesting implications for precip changes under solar geo and paleoclimate scenarios
notesonclimate.substack.com
A Spectral Model of CO2's Surface Forcing
Summary of Yue et al. (2026)
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Reposted by Nick Lutsko
Shiv Priyam Raghuraman @rshivpriyam.bsky.social · 19/06/2026
We are hiring a postdoc to research Earth's Energy Imbalance using Earth system model simulations and satellite observations. I appreciate anyone spreading the word! docs.google.com/document/d/1...
docs.google.com
Postdoctoral Research Associate Position in Earth’s Energy Imbalance
Postdoctoral Research Associate Position in Earth’s Energy Imbalance Department of Climate, Meteorology & Atmospheric Sciences, University of Illinois Urbana-Champaign The Department of Climate, Mete...
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elizabethginexi.bsky.social @elizabethginexi.bsky.social · 29/05/2026
Summary of Key Changes in OMB’s Proposed Federal Financial Assistance Rule. Russell Vought is going destroy American Science. elizabethginexi.substack.com/p/summary-of...
elizabethginexi.substack.com
Summary of Key Changes in OMB’s Proposed Federal Financial Assistance Rule
Russell Vought is going destroy American Science
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Nick Lutsko @nick-lutsko.bsky.social · 18/05/2026
The RCP8.5 story just seems like good scientific process: 1. we explored a wide scenario space when future warming (emissions & climate sensitivity) was uncertain 2. we focused on high-end cases because damages are nonlinear/tail risks 3. we updated to a narrower scenario space as more data come in
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Nick Lutsko @nick-lutsko.bsky.social · 15/05/2026
The research itself isn’t necessarily problematic- academic labs do similar work. I worry the VC-backed setup incentivizes deployment, but at this stage the field’s job is to read the papers carefully, ask for more data and emphasize that there are many questions about SAI beyond strat chemistry
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Nick Lutsko @nick-lutsko.bsky.social · 15/05/2026
l’m becoming more sympathetic to Stardust. Past the hype, they’ve raised substantial funding to investigate a promising candidate material for SAI and are now releasing papers. This wouldn’t be unusual in pharma www.nytimes.com/2026/05/14/c...
nytimes.com
Can Some Very Tiny Particles Cool the Planet? One Tech Company Says Yes.
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Nick Lutsko @nick-lutsko.bsky.social · 12/05/2026
This is nice
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Reposted by Nick Lutsko
American Meteorological Society @ametsoc.org · 05/05/2026
From curiosity about nature to leading next-gen climate models, Tapio Schneider, 2026 AMS Jule Charney Medal winner, reflects on his work and the future of climate science. Discover the conversation and what lies ahead for climate science: bit.ly/4whEcn4
headlines.ametsoc.org
Award Spotlight: A Conversation with Tapio Schneider
Tapio Schneider is the 2026 recipient of the Jule Charney Medal, recognized “for pioneering research on atmospheric dynamics and climate change and leadership in innovative climate model development.”...
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Nick Lutsko @nick-lutsko.bsky.social · 01/05/2026
For all the debates in climate, we’re pretty good Bayesians (or at least the scenario builders are)
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Nick Lutsko @nick-lutsko.bsky.social · 28/04/2026
This crescent Earth photo from Artemis shows a nice cross section through the atmosphere, with blue edges where the light passes through the clear upper atmosphere and is Rayleigh scattered and a white middle where the light passes through clouds and aerosols in the lower atmosphere
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Nick Lutsko @nick-lutsko.bsky.social · 28/04/2026
Glad to see someone finally test QRWA in an idealized setting. It’s always felt like a big jump to go from the linearized 2D vorticity equation (w/many assumptions) to the real atmosphere, where there are many confounding factors
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Reposted by Nick Lutsko
Shiv Priyam Raghuraman @rshivpriyam.bsky.social · 24/04/2026
New paper on cloud feedbacks out! urldefense.com/v3/__https:/... Should an enhanced East Pacific warming pattern manifest at equilibrium, our results suggest that CESM2’s high climate sensitivity may be realized.
urldefense.com
Cloud feedback overestimated in coupled CESM2 simulations relative to AMIP simulations and satellite observations: importance of the pattern effect and implications for climate sensitivity
Cloud feedback overestimated in coupled CESM2 simulations relative to AMIP simulations and satellite observations: importance of the pattern effect and implications for climate sensitivity, Raghuraman...
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Nick Lutsko @nick-lutsko.bsky.social · 23/04/2026
Wrote a follow-up to my last post, on the nuances of model diversity. We've certainly benefited from developing new models and exploring parameter space, but have spent less time establishing reference model hierarchies "of lasting value" notesonclimate.substack.com/p/model-dive...
notesonclimate.substack.com
Model Diversity and Model Hierarchies
"A" hierarchy, or "the" hierarchy?
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