Chris Smith

CMIP Community Workshop 2026 - Coupled Model Intercomparison Project The CMIP Community Workshop 2026 will bring together a growing, and increasingly diverse, community of Earth system scientists, partners, and stakeholders. It

We (@tim-andrews.bsky.social, Ryan Kramer and I) are leading a session around understanding radiative forcing in models at the CMIP Community Workshop in Kyoto, Japan, next March. Abstract submissions open until 13 August:

wcrp-cmip.org/event/cmip20...
Session ID #4

Introducing 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...

Including a climate module and climate damages within a process-based integrated assessment model: meet FRIDA.

egusphere.copernicus.org/preprints/20...

Hello world, who else is in Vienna this week?

Please get in touch with Team @carbonbrief.org if you're in Bonn this week – @mollylempriere.carbonbrief.org + @joshgabbatiss.bsky.social have just arrived

In this Carbon Brief post we talk about the implications of not including future volcanic eruptions in climate scenarios, as described in our recent paper: www.nature.com/articles/s43...

I'll be giving a short talk on 1.5°C at a mini-symposium at VUB on Friday 6 June as part of an event celebrating the award of an honorary doctorate to @joerirogelj.bsky.social, see below for details and registration!

Some sessions that ought to be fun & interesting:

🔷 ID4 RFMIP: Exploring radiative Forcing in models and observations to understand climate change

🔷 ID5 CERESMIP: Confronting models with observed changes in the Earth’s energy imbalance

🔷 ID15 CFMIP: Clouds, circulation and climate sensitivity

Very cool that @carbonbrief.org @ayeshatandon.carbonbrief.org have covered our study, take a read here!

New paper on the risks of forest ecosystem impacts under emissions pathways designed to meet the Paris Agreement temperature goals is out today in Nature Climate Change! 🌳

Read it here: www.nature.com/articles/s41558-025-02327-9

To all of my friends in Oslo, I am presenting at the Joint Oslo Seminar tomorrow at UiO! It will be the full-fat version of my EGU talk:

Updated IPCC emissions scenarios no longer limit warming to 1.5°C

Details 👇

www.mn.uio.no/geo/english/...

Very excited to announce that the call for abstracts for our @iiasa.ac.at overshoot conference is out.

Join us to explore the eightfold path to manage climate risks of an overshoot world:
overshootconference.org
Abstract deadline: June 27.

It should be, but I don't know if this will happen again this year. So get in early :)

Indicators of Global Climate Change 2024: annual update of key indicators of the state of the climate system and human influence Abstract. In a rapidly changing climate, evidence-based decision-making benefits from up-to-date and timely information. Here we compile monitoring datasets (published here https://doi.org/10.5281/zen...

The preprint for Indicators of Global Climate Change 2024 is now up for public discussion in ESSD.

essd.copernicus.org/preprints/es...

Here's @arp-climate.bsky.social presenting on the upcoming process-based carbon cycle in FaIR at #EGU25!

It's subtle. I'll show you in Oslo

Is 1.5°C still within reach? Find out tomorrow (Tuesday) at #EGU25

09:15, room 0.31/32, session CL3.2.1

meetingorganizer.copernicus.org/EGU25/EGU25-...

Foundation-funded postdoc funding opportunity to work in WA state! Interested in applying to work with me on climate on land or global carbon cycle dynamics? Reach out! Info sessions in May and June, due date June 26. www.wrfseattle.org/grants/wrf-p...

Some of the WorldTrans crew at EGU25 with Axel's poster 👏

Ah nice, thanks!

Differences in anthropogenic greenhouse gas emissions estimates explained Abstract. We examine differences in global and national greenhouse gas (GHG) emissions estimates and highlight the important role of varying system boundaries and conceptual approaches in driving thes...

New preprint: differences in anthropogenic greenhouse gas emissions explained essd.copernicus.org/preprints/es...

awesome study, and fair is all over it (cheers for the shout out @ccallahan45.bsky.social!)

🎡 ✨🚢 Next week, at EGU-2025, I will be co-chairing a session on shipping-related emissions. The session will feature contributions on a range of topics, including emission inventories, radiative impacts, in-situ measurements, weather routing, and agentic AI. More at 👉 lnkd.in/dyYwiN-v @cjsmith.be

Starting to think I might be the only person left on planet Earth who still believes that Hunga Tonga is (and continues to be) a net positive climate forcer. Should probably write a paper

Investigating carbon and nitrogen conservation in reported CMIP6 Earth system model data Abstract. Reliable, robust, and consistent data are essential foundations for analysis of carbon cycle feedbacks. Here, we consider the data from multiple Earth system models (ESMs) participating in t...

Hi Bluesky! 👋 I'll get the ball rolling by sharing a paper I contributed to and has recently been published in GMD: gmd.copernicus.org/articles/18/....

We took a look at carbon and nitrogen data from CMIP6 climate models and found some significant mass imbalances in the reported data.

Guest post: How to apportion ‘net-zero carbon debt’ if global warming overshoots 1.5C - Carbon Brief Our findings show that some regions, such as western Europe and North America, will accrue net-zero carbon debt as soon as 2030.

NEW – Guest post: How to apportion ‘net-zero carbon debt’ if global warming overshoots 1.5C | @setupelz.bsky.social @robinlamboll.bsky.social @wimthiery.bsky.social @gidden.bsky.social @cjsmith.be @shonali-p.bsky.social

Read here:

Yes there is: scenariosforum.org/registration...

Scenarios Forum 2025: abstract submission deadline extended until 7 April

scenariosforum.org/call-for-abs...

Clarifying point: current scenarios do have a representation of volcanic forcing that is equal to the historical mean, they just don't actually simulate realistic sporadic eruption events

Of course; we should not assess Paris Agreement compliance based on a lucky well-timed volcanic eruption, but a reminder that we measure, and feel impacts, based on total warming, whereas policy-relevant analysis should focus on the (imperfectly measurable) human-driven component.

two panel plot showing (top) the probability of exceeding 1.5°C in three climate scenarios (ssp119: very low emissions; ssp245: moderate emissions; ssp585: very high emissions). Bottom: the difference in probability over time of crossing 1.5°C when including sporadic eruptions compared to the standard time-average approach used in climate model projections.

As a corollary, we can also see what this does to projected thresholds of warming exceedance in different scenarios; including volcanoes lowers the probability of exceeding 1.5°C by 5-7% in a very high ambitious scenario.