Chris Smith

New paper in ERL in which we study the effect of a long-known issue in climate emulators: that we typically calibrate them on only 150 years of 4xCO2 ESM runs. This a problem as we know the climate isn't in equilibrium after this time, but running ESMs is 1/N

iopscience.iop.org/article/10.1...

How well can we quantify when 1.5 °C of global warming has been exceeded? Abstract. Parties to the 2015 Paris Agreement agreed to limit the long-term increase in global average temperature to well below 2 °C and pursue efforts to keep temperatures below 1.5 °C relative to p...

New discussion paper just dropped that’s taken shall we say a little work to get this far … essd.copernicus.org/preprints/es... please be kind. Not on an at all sensitive topic in the slightest.

yeah... it's an offset relative to a historical (1750-2021) mean. The dips are due to large volcanic eruptions. "On average" the historical natural forcing is zero. I argue to use a truly pre-industrial reference for natural forcings as we did in IPCC AR6, but this doesn't make a big difference

D & A style attribution with fair and HadCRUT5 updated to 2025 (emissions extrapolated beyond 2022, but should make little difference)

[code: github.com/chrisroadmap...

Feedback-based sea level rise impact modelling for integrated assessment models with FRISIAv1.0 Abstract. Global warming is expected to lead to a substantial rise in coastal sea levels by the end of the century, which imposes future impacts and adaptation challenges on the coastal zone. Capturin...

The FRISIA sea-level rise model description is published today and selected as a highlight paper in Geoscientific Model Development gmd.copernicus.org/articles/18/...

FRISIA is designed to couple with IAMs, but can also be run standalone for sea-level rise projections from emissions scenarios.

Call Me Charney: A GFD Parody This was so fun to make!! #lamontdoherty #lamont #atmosphere #science #charney #GFS #vallis #geostrophic #quasigeostrophic #hydrostatic #rossby

This is the only parody song about geophysical fluid dynamics you’ll ever need:

urldefense.com/v3/__https:/...

Analysis: What are the causes of recent record-high global temperatures? - Carbon Brief In this article, Carbon Brief explores four different factors that have been proposed for the exceptional warmth seen in recent years

Beautiful analysis once again @hausfath.bsky.social

www.carbonbrief.org/analysis-wha...

I'm looking for projections of agricultural water withdrawal into the future (UN FAO have historical data, e.g. fig. 13 in openknowledge.fao.org/server/api/c...). So much the better if they are tied to SSPs.

Climate Change, Volume 2 Our climate refers to the different types of weather we have all around the world. Some places are hot, some are cold, some are dry and some are wet. But now, our climate is changing and it's affectin...

The Frontiers for Young Minds Climate Change Volume 2, guest edited by me, @chrisd-jones.bsky.social and @leilaniamir.bsky.social, is now complete!

Also collected into a nice e-book!

kids.frontiersin.org/collections/...

Science for kids, peer-reviewed by kids

🌍Two members of our department @cjsmith.be and @harryzeko.bsky.social joined the first IPCC AR7 lead author meeting in Saint-Denis (Paris).

#IPCC #AR7 #ClimateScience #WG1 #ClimateAction

#EGU26 session on climate change emulation for impact projections.

Please share with anyone who works on simple climate models, statistical / ML / hybrid approaches, pattern scaling, emulators, real-world impact studies 🌍

📩 Abstract submissions are open.
🔗 Session info: www.egu26.eu/session/56612

⚖️ Are you working on topics that could be relevant for climate litigation?

➡️ Submit an abstract to our outreach session (which allows you to submit a second abstract)
#EGU26

meetingorganizer.copernicus.org/EGU26/sessio...

Reduced Complexity Model Intercomparison Project Phase 3: Experimental protocol for coordinated constraining and evaluation of Reduced-Complexity Models Abstract. Reduced-Complexity Models (RCMs) are a critical tool for synthesising climate science knowledge and providing climate projections for a wide range of emissions scenarios. The Reduced-Complex...

Reduced Complexity Model Intercomparison Project Phase 3 preprint: egusphere.copernicus.org/preprints/20...

In parallel to experiments run by complex climate models, we evaluate the simple climate models that are used as translations of knowledge from physical science to scenario projections

Cool, thanks Abby! I was aware of this paper but don't think I cited it (my bad) - the running to 2300 is there and we can compare the carbon sinks, but the experiments were concentration-driven, and didn't include the lower scenarios, and they don't have NorESM, which is a super interesting model!

Unfortunately not. These were from the CMIP6 ESGF - was really a shame that not many models extended beyond 2100.

temperature and CO2 projections from MPI-ESM1.2-LR and NorESM2-LM under three emissions scenarios to 2300

A sneak peak of hopefully what is to come in CMIP7. We ran two CMIP6 climate models in CO2 emissions driven mode to 2300 - and the responses in the long term are very different.

Preprint: egusphere.copernicus.org/preprints/20...

An overview of FRIDA v2.1: a feedback-based, fully coupled, global integrated assessment model of climate and humans Abstract. The current crop of models assessed by the Intergovernmental Panel on Climate Change (IPCC) to produce their assessment reports lack endogenous process-based representations of climate-drive...

The FRIDA overview paper: gmd.copernicus.org/articles/18/...

A coupled human-Earth IAM, with integrated climate impacts.

I should have known this...

There are 1.5°C no and low overshoot scenarios in AR5, but they are cooler in 2020 than we have observed, suggesting that mitigation would have started in the 2010s.

It would be good to do this consistently harmonized in the same simple climate model

yeh, precisely this! I mean, one of the successes of the Paris Agreement (or failure of pre-Paris climate policy?) is that nobody was really looking at 1.5°C scenarios before 2016. I'm just interested to see if anyone has done a like-for-like climate comparison. If not, I might :)

GHG and CO2 emissions plumes from emissions scenarios submitted to the IPCC Fifth Assessment Report Working Group III.

Has anybody ever looked at the IPCC AR5 scenario database and run them in a simple climate model? I'm curious to know how many would get close to 1.5°C - probably not many if the earliest net zero CO2 date is ~2060. Interesting to see how ambition has evolved over time at the low end

Rapid emissions cuts would avoid 64cm of ‘locked in’ sea level rise by 2300 - Carbon Brief Cutting emissions in line with the 1.5C warming limit, rather than following current climate policies, could curb long-term sea level rise by 64cm.

Carbon Brief article on our committed sea-level rise paper: www.carbonbrief.org/rapid-emissi...

Multi-century global and regional sea-level rise commitments from cumulative greenhouse gas emissions in the coming decades - Nature Climate Change It is important to understand how much long-term sea-level rise is already committed due to historical and near-term emissions. Here the authors use a modelling framework to show how decisions on glob...

Really important paper led by my @iiasa.ac.at colleague Alex Nauels www.nature.com/articles/s41...
“The difference between decisive climate action today and continued high emissions is not just measured in degrees of warming but also in meters of sea-level rise” 👏👏👏

windows will restart now

How to contribute to fair:
✅submit a pull request
✅wait 6 months
✅track me down in person and remind me to review it

v2.2.3 now available at the usual places.

pypi.org/project/fair
anaconda.org/conda-forge/fair

I know!!! I was outvoted

The Radiative Forcing Model Intercomparison Project (RFMIP2.0) for CMIP7 Abstract. An external perturbation to the climate system from anthropogenic or natural activity first impacts the climate by inducing a perturbation to Earth’s energy budget, known as a radiative forc...

RFMIP2 preprint now out! egusphere.copernicus.org/preprints/20...

If you want to get your simple climate model picked up by IPCC AR7, see below 👇

We have 11 on our radar from the previous round of RCMIP (egusphere.copernicus.org/preprints/20...), plus a few others we found since.

Anybody we don't know about please ping me or Alex

flat10MIP: an emissions-driven experiment to diagnose the climate response to positive, zero and negative CO2 emissions Abstract. The proportionality between global mean temperature and cumulative emissions of CO2 predicted in Earth system models (ESMs) is the foundation of carbon budgeting frameworks. Deviations from ...

flat10-MIP has landed! gmd.copernicus.org/articles/18/...

send me a PM :)

Belspo press release on the Belgian contribution to IPCC AR7:

FR: www.belspo.be/belspo/organ...
NL: www.belspo.be/belspo/organ...
EN: google translate ;)