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Ben Sanderson

@benmsanderson.bsky.social
10K followers 1.6K following 809 posts

Climate scientist at CICERO, Oslo. I try to talk about climate science, but inevitably start talking about trains and bicycles if left unattended.

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Reposted by Ben Sanderson
The Analyst @militaryanalyst.bsky.social · 17/09/2026
CANADA & THE EU The speed at which Canada is preparing to change direction and move economically and politically towards the EU has shaken the Americans. They can't believe that Canada even has an alternative path that doesn't involved the US, let alone that the country might become a willing
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Reposted by Ben Sanderson
David Ho @davidho.bsky.social · 15/09/2026
NSF has reduced the research budget for all atmospheric, ocean, and earth sciences by ~80%. 80%! A lot of us will not be conducting new research or training new students for the foreseeable future.
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Reposted by Ben Sanderson
Jason Kint @kint.bsky.social · 17/09/2026
Eye popping. Court just unsealed Summary Judgment motions in New York Times v OpenAI / Microsoft. Easy to see why the AI companies had so many redactions (pink). Their own people wrote the lede for NYT, the "largest theft of labor in human history"... "more and more substitutive..." /1
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Reposted by Ben Sanderson
Giuseppe Di Caprio @giudica.bsky.social · 17/09/2026
"This decline in atmospheric dust has exerted a positive effective radiative forcing of +0.02 ± 0.05 watts per square meter over 2003–2023, implying that declining atmospheric dust might have modestly contributed to the rapid warming of the past two decades."
science.org
A global decline in atmospheric dust during the 21st century
Mineral dust affects Earth’s energy budget, clouds, and biochemistry, yet the evolution of the global dust cycle in recent decades remains shrouded in uncertainty. Here we reconstruct the global dust ...
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Reposted by Ben Sanderson
Crawford Kilian @crof.bsky.social · 17/09/2026
El Niño goes viral — and scientists learn what makes people care about the climate www.nature.com/articles/d41...
nature.com
El Niño goes viral — and scientists learn what makes people care about the climate
Evoking emotions is more likely to prompt people to engage with climate efforts than are data alone.
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Reposted by Ben Sanderson
Palok Biswas @pbiswas.bsky.social · 01/07/2026
🎉 Our paper is out in Nature Portfolio npj Climate Action! 👉 📃 www.nature.com/articles/s44... 𝐊𝐞𝐲 𝐟𝐢𝐧𝐝𝐢𝐧𝐠: The choice of justice framing in climate models fundamentally determines both the global ambition for decarbonization and who bears its burden.
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Reposted by Ben Sanderson
Abigail Swann, PhD @ecoclimatelab.bsky.social · 09/09/2026
We have a new paper on the response of land carbon to zero, declining, and negative emissions of CO2 across Earth System Models! w/ @ckoven.bsky.social @cristiproist.bsky.social @rosieafisher.bsky.social @benmsanderson.bsky.social & more (1/6) esd.copernicus.org/articles/17/...
esd.copernicus.org
Land carbon response to positive, zero, and negative CO2 emissions across Earth system models
Abstract. Land carbon sinks are responsible for removing about a quarter of anthropogenic CO2 emissions, and make up approximately half of total global carbon sinks. Uncertainty in the response of lan...
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Ben Sanderson @benmsanderson.bsky.social · 13/09/2026
Whether or not ‘big AI’ is inflating the risk, I really wish governments would take a bigger role in legislating responsible development and testing practices and actually hold them liable for damages - rather than leaving companies to self regulate and further exaggerate their own god complex.
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Ben Sanderson @benmsanderson.bsky.social · 16/07/2026
Watching the news in france last night was wall to wall climate impacts - heatwaves, wildfires, crop failures. We spent the well hiking around melted glaciers on Mont Blanc, and our last night here brings crazy thunderstorms. Climate anxiety not exactly being calmed by this holiday...
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Ben Sanderson @benmsanderson.bsky.social · 05/07/2026
The anti-woke lot know that air conditioners ARE heat pumps ... right? www.theguardian.com/environment/...
theguardian.com
From ‘heat panic’ to ‘sacrificed at the altar’: Europe’s air conditioning culture wars heat up
Cooling down has become political amid record highs, as experts say row is distracting from work of protecting lives
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Ben Sanderson @benmsanderson.bsky.social · 27/06/2026
Note that the website draws a blend of ERA5T reanalysis and live forecast data - the plots and exact numbers are going to shift about a bit until the event is covered by reanalysis
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Ben Sanderson @benmsanderson.bsky.social · 27/06/2026
Another way of slicing it - for event as rare as this one (~1 in 40 years), the hottest-day French national-average temperature would be: - 1.0 °C hotter in a 2 degreeC world - 2.6 °C hotter in a 3 degreeC world So, the national average extreme warming runs about ~1.6× faster than global mean temp
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Ben Sanderson @benmsanderson.bsky.social · 27/06/2026
I think Hansen is wrong on the *magnitude* of warming in the pipeline - as we lay out here (he doesn't properly factor in the carbon cycle response into the committed warming) egusphere.copernicus.org/preprints/20... But the uptick is real - and there's real uncertainty on the role of aerosols.
egusphere.copernicus.org
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Ben Sanderson @benmsanderson.bsky.social · 27/06/2026
Just spent a solid 30 seconds wondering why Vector Auto Regression (VAR) was a trending topic
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Ben Sanderson @benmsanderson.bsky.social · 27/06/2026
This is not to say bringing down methane emissions wouldn't help - it most certainly would. But methane alone doesn't explain why we've seen an uptick in warming rate.
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Ben Sanderson @benmsanderson.bsky.social · 27/06/2026
The big uncertainties are in how the aerosol forcing has changed recently, how climate feedbacks respond to that differently to CO2 changes, and when we see slow and fast timescale changes emerge in the system.
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Ben Sanderson @benmsanderson.bsky.social · 27/06/2026
Not really the point of this analysis - methane is super important, but it doesn't add up that it's the dominant driver of recent warming. We know the atmospheric methane concentrations and their associated forcing - co2 and aerosols are the biggest movers. essd.copernicus.org/articles/18/...
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Ben Sanderson @benmsanderson.bsky.social · 27/06/2026
Sorry for the delete/repost - first version had a stale plot.
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Ben Sanderson @benmsanderson.bsky.social · 27/06/2026
Recent French national average temperatures: - impossible in a pre-industrial world, - about 1 year in 40 years in a 1.5C world - 1 in 10 years in a +2 °C world - 3 degree world - happens every other year interactive/method/maps here (également en français): benmsanderson.github.io/futureevent/
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Ed Hawkins @edhawkins.org · 26/06/2026
What is the future of summers in England? Our choices matter. A high-emissions future will commit our children and grandchildren to live in a world where the summers of 1976 & 2025 are cold. A global net-zero emissions future means that we can stabilise the climate & those summers will be normal.
England average summer temperatures in a high emissions futureEngland average summer temperatures in a global net-zero emissions future
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Reposted by Ben Sanderson
Larry Neufeld @larryneufeldsk.bsky.social · 24/06/2026
Can you blame climate scientists for getting disgusted with politicians?: Climate scientists appalled by politicians' refusal to accept responsibility as heatwave hits France www.lemonde.fr/en/environme...
lemonde.fr
Climate scientists appalled by politicians' refusal to accept responsibility as heatwave hits France
Valérie Masson-Delmotte, Jean Jouzel and Christophe Cassou say that years of warnings issued from scientists about the consequences of global warming have not been taken more seriously.
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Reposted by Ben Sanderson
Nature @nature.com · 02/06/2026
A US federal judge has ruled against the Trump administration, preventing it from handing off a piece of the National Center for Atmospheric Research (NCAR). See how we covered the battle over NCAR as it kicked off in court last month. go.nature.com/4u3jvIV
go.nature.com
World-leading climate centre takes Trump administration to court
Universities that run the National Center for Atmospheric Research want to keep it from being dismantled.
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Reposted by Ben Sanderson
Michael E. Mann @michaelemann.bsky.social · 01/06/2026
Court blocks Trump/GOP/Project 2025 effort to dismantle NCAR: www.courtlistener.com/docket/72496...
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Reposted by Ben Sanderson
Paul Voosen @voosen.me · 01/06/2026
Score one for NCAR/UCAR.
science.org
Court blocks NSF’s transfer of climate lab’s supercomputing facility
Proposed switch in management caused irreparable harm to NCAR, judge finds
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Reposted by Ben Sanderson
Alexandra Witze @alexwitze.bsky.social · 01/06/2026
NCAR just won in court! A US district judge in Colorado has prohibited NSF from taking #NCAR apart, specifically in spalling off its supercomputing center in Wyoming. storage.courtlistener.com/recap/gov.us... Our earlier story on this and why it matters: www.nature.com/articles/d41... 🧪
nature.com
World-leading climate centre takes Trump administration to court
Universities that run the National Center for Atmospheric Research want to keep it from being dismantled.
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Ben Sanderson @benmsanderson.bsky.social · 24/05/2026
The method also has limits, we fit a 2-box model and we show it has limite and cannot fit ESM responses to deep negative emissions - so the net removal response can't be decomposed the same way. Preprint is open for comments- all thoughts most welcome.
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Ben Sanderson @benmsanderson.bsky.social · 24/05/2026
But big caveat with all this - is that it's based on CMIP6 era models, and we know that there are issues on the thermal side (they got warming patterns wrong) and the carbon side (they might be missing carbon tipping points).
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Ben Sanderson @benmsanderson.bsky.social · 24/05/2026
But, that said, not all models are the same. Some models (e.g. UKESM) are thermal dominated - where ZEC is positive and expected to increase as warming increases, and as emissions rate increases. Others (like CESM) are carbon dominated - ZEC is negative and gets moreso at high emissions rates.
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Ben Sanderson @benmsanderson.bsky.social · 24/05/2026
Does this mean ECS doesn't matter? Quite the opposite. The thermal term carries more than twice the inter-model spread of the carbon term. ZEC uncertainty (on a 50 year timescale) is dominated by ECS and the ocean heat timescale (but on multi-century timescales, the carbon cycle dominates.)
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Ben Sanderson @benmsanderson.bsky.social · 24/05/2026
Quantitatively, on average for the ESMs - a 10% drop in realised warming fraction adds ~0.5 K of committed warming, but shifts 50-year ZEC by ~0.05 K. The carbon is removed before the unrealised warming shows up. So the pipeline debate, real as it is, is largely decoupled from the carbon budget.
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Ben Sanderson @benmsanderson.bsky.social · 24/05/2026
The pipeline literature talks about realised warming fraction - how much the system has warmed relative to radiative equilbrium. But (if we stopped emitting today) that equilbrium never happens because the oceans and land would continue to take up carbon
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Ben Sanderson @benmsanderson.bsky.social · 24/05/2026
Work by Hansen etc says the pattern effect has hidden a big "warming in the pipeline." Revise the realised warming fraction down and committed warming jumps by half a degree. But if this is true, does it make a difference to remaining carbon budgets? maybe not... academic.oup.com/oocc/article...
academic.oup.com
Global warming in the pipeline
Abstract. Improved knowledge of glacial-to-interglacial global temperature change yields Charney (fast-feedback) equilibrium climate sensitivity 1.2 ± 0.3°
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Ben Sanderson @benmsanderson.bsky.social · 24/05/2026
We fit a simple coupled carbon-climate model to each ESM and get a clean analytical formula for ZEC. It reproduces the models to within ~0.03 K. This allows you to read off which parameters matter. And the spread is thermal, not carbon, by more than a factor of two.
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Ben Sanderson @benmsanderson.bsky.social · 24/05/2026
When CO2 emissions stop, two things happen. The deep ocean keeps delivering unrealised warming in response to energetic imbalance, while land and ocean sinks keep drawing CO2 down - reducing the imbalance. The relative rate and saturation of these two processes decides how much warming you get.
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Ben Sanderson @benmsanderson.bsky.social · 24/05/2026
We have a new preprint this week. When CO2 emissions stop, warming in the pipeline is controlled by two big opposing effects - thermal response to energetic imbalance *and* carbon sink evolution. We assess their roles in the flat10MIP ensemble /thread/ egusphere.copernicus.org/preprints/20...
egusphere.copernicus.org
Decomposition of the Zero Emissions Commitment into thermal warming pipeline and carbon buffering components
Abstract. The Zero Emissions Commitment (ZEC), the residual warming after anthropogenic CO2 emissions cease, remains poorly constrained and directly affects remaining carbon budget calculations. We fi...
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Ben Sanderson @benmsanderson.bsky.social · 13/05/2026
One datacenter. 9GW. powered entirely by natural gas turbines is about 31 million tonnes of CO2 per year. About the same as Switzerland. www.theguardian.com/us-news/2026...
theguardian.com
‘Irresponsible’: backlash as Utah approves datacenter twice the size of Manhattan
Facility would require more power than entire state uses and suck up vast amount of water in drought-stricken area
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Reposted by Ben Sanderson
Scientific American @sciam.bsky.social · 09/05/2026
Universities that run the National Center for Atmospheric Research want to keep it from being dismantled
scientificamerican.com
Top climate research center at risk of cuts sues Trump administration
Universities that run the National Center for Atmospheric Research want to keep it from being dismantled
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Ben Sanderson @benmsanderson.bsky.social · 08/05/2026
Hopefully these are useful to the wider community - and if you develop further, I'd encourage you to contribute to the repos! (also - feel free to drop an issue on github if things don't work as expected)
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Ben Sanderson @benmsanderson.bsky.social · 08/05/2026
pyCMAT is a python port of (some of) John Fasullo's CMAT climate diagnostic package. It produces nice comparative graphics and html summariees of ESM performance between versions, and can download CMIP6 data for comparison. github.com/benmsanderso...
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Ben Sanderson @benmsanderson.bsky.social · 08/05/2026
ncview2 is a relatively faithful python port of David Pierce's ncview. It handles non-uniform grids, and can perform on-the-fly area averaging with multiple color maps. github.com/benmsanderso...
github.com
GitHub - benmsanderson/ncview2
Contribute to benmsanderson/ncview2 development by creating an account on GitHub.
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Ben Sanderson @benmsanderson.bsky.social · 08/05/2026
Hi everyone, in the course of NorESM development for CMIP7 - we've had need to do some rapid benchmarking and diagnostics. To this end, I've made a couple of tools which might be useful for the wider community - python ports of ncview and CMAT. /thread/
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Ben Sanderson @benmsanderson.bsky.social · 05/05/2026
Hi everyone, gridded data for the flat10MIP project is now open and public on the Norwegian Research Data Archive. Research using these data for understanding carbon-climate feedbacks, including climate commitment and reversibility is super relevant for AR7-WG1. archive.sigma2.no/dataset/flat...
archive.sigma2.no
Sigma2 Data Catalogue
Sigma2 Data Catalogue
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Ben Sanderson @benmsanderson.bsky.social · 08/04/2026
Finally - a huge thankyou to Zeb, Marit, Jarmo and Marco - who worked massively hard to make the backend to this process work. This code is all public on github. github.com/iiasa/emissi...
github.com
GitHub - iiasa/emissions_harmonization_historical: Scripts that combine historical emissions data records from several datasets like CEDS and GFED to create complete historical emissions for `IAMconso...
Scripts that combine historical emissions data records from several datasets like CEDS and GFED to create complete historical emissions for `IAMconsortium/concordia` and `iiasa/climate-assessment`....
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Ben Sanderson @benmsanderson.bsky.social · 08/04/2026
It's taken some time. There are good reasons for this - we took the community consultation seriously and made real changes to the design; ScenarioMIP bridges many communities across ESMs, IAMs and observations - and finding consensus, common language and technical solutions takes time.
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Ben Sanderson @benmsanderson.bsky.social · 08/04/2026
Extensions: we're working with PNNL/LUH on translating the global land use pathways transitions to gridded land use transitions in a smooth way which approximately represents the AFOLU target trajectory. These should be done soon - with a dedicated paper on methodology.
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Ben Sanderson @benmsanderson.bsky.social · 08/04/2026
VL & H are up on Input4MIPs already. Global/regional emissions are finalised already and gridded data ESM input data will be published in the coming weeks. input4mips-cvs.readthedocs.io/en/latest/da...
input4mips-cvs.readthedocs.io
Summary - input4MIPs Controlled Vocabularies (CVs)
Controlled Vocabularies (CVs) for use in input4MIPs
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Ben Sanderson @benmsanderson.bsky.social · 08/04/2026
New in the final version: a dedicated section on natural forcings (solar; volcanic), a discussion scenario likelihood, and on equity and justice considerations in scenario design. egusphere.copernicus.org/preprints/20...
egusphere.copernicus.org
Stratospheric aerosol forcing for CMIP7 (part 1): Optical properties for pre-industrial, historical, and scenario simulations (version 2.2.1)
Abstract. Stratospheric aerosols, most of which originate from explosive volcanic sulfur emissions into the stratosphere, are a key natural driver of climate variability. They are thus a forcing provi...
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Ben Sanderson @benmsanderson.bsky.social · 08/04/2026
For CMIP7: most scenarios are designed to be run in emissions-driven mode, meaning carbon cycle feedbacks are part of the experiment rather than prescribed away - as we laid out here. This motivates effort to reproduce historical CO2 concentrations. egusphere.copernicus.org/preprints/20...
egusphere.copernicus.org
EGUsphere - The need for carbon emissions-driven climate projections in CMIP7
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Ben Sanderson @benmsanderson.bsky.social · 08/04/2026
We also provide a more extensive assessment of the assumed removals in the extensions - putting cumulative removal assumptions in the context of limits to geological storage (and - spoiler alert: HL/LN extensions are challenged by these assessments) www.nature.com/articles/s41...
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Ben Sanderson @benmsanderson.bsky.social · 08/04/2026
We revised scenario extensions to 2500 after review: smoother transitions at 2100, continuous derivatives across all forcing species, and land-use fluxes ramped to zero by 2150 rather than CMIP6 step-changing. The most extreme overshoot extension (H-ext-OS) was dropped in favour of HL-ext.
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