Justin Ritchie

A series of tweets projected in general equilibrium // co-founder @transitionshow XE Network & more

[Transition Show @[email protected] @TransitionShow]

Ep. 277 wraps up our miniseries on South Africa, exploring how its economic development depends heavily on leaving behind its coal-fired legacy electricity system and making a “just transition” to renewables. https://t.co/z2zZ7XPXRR

[Transition Show @[email protected] @TransitionShow]

In @TransitionShow Ep. 276, we check out one of the most exciting #energytransition stories in the world: South Africa is transitioning its electricity system from a state-owned monopoly to a free market, and from coal to renewables. https://t.co/QeMwd0puiB

[Justin Ritchie @jritch]

Given recent discussions on RCP8.5, I was prompted to look back at how my co-author Hadi and I got the concept of its implausibility initially published in 2017.

After attempts in journals where climate scenarios are typically covered, the tally before "Why do climate change scenarios return to coal?" finally landed in 2017 was: 6 journals, 5 rejections, 1 denied appeal, ~8 submission events, 3 revision rounds, 10+ reviewers.

Revisiting this sequence reminded me of what the reviewers wrote to support the rejection decisions:

[Rejected]
June 8, 2017: "I tend to agree with the conclusion that RCP8.5 is an unlikely extremely high emission scenario, which is abused in impacts studies as 'baseline' at the moment." (Reviewer #1)

[Recommended revision, then later rejected]
January 24, 2017: "RCP8.5 and SSP5 are not BaU scenarios… well-known within the IAM community… but has not been picked up by the user community." (Reviewer #1)

[Rejected]
June 24, 2016: "Important topic adroitly handled… It's an excellent and useful paper. I don't have any specific recommended changes to make. Hopefully this will lead to re-thinking the RCP scenarios." (Reviewer #2)

[Justin Ritchie @jritch]

Self-correction in climate science may proceed on decadal timescales.

Thanks to @RogerPielkeJr @hausfath @MLiebreich @Peters_Glen @matthewgburgess @Revkin for their early detection and staying engaged the whole way on this recalibration.

https://t.co/WfDyAEwJvs

[Matt Burgess @matthewgburgess]

Lots to agree with in his post, but, with respect, his assertion that climate policy explains the difference between RCP8.5 and the new high scenario is wrong.

That's why, for example, @jritch was able to publish a paper in 2017 showing that the coal assumptions of RCP8.5 strained physical credulity. We also knew about the implausibility issues (caused by coal, economic growth, pessimistic renewable tech assumptions, etc.) enough back in the early 2020s that IPCC AR6 explicitly mentioned them, citing @hausfath's paper, ours, and Justin's. (Justin, @RogerPielkeJr and I drew the below figure in 2022.) And yet, 8.5 still dominated the literature and the AR6 WGII assessment (see the figure). IEA's CPS and STEPS scenarios have been way off RCP8.5 for years and getting gradually more optimistic. Even the creators of RCP8.5 intended it to be a worst-case scenario, not "business as usual".

Anyway, I think these new CMIP7 developments show that the field is updating (contrary to what some critics assert), but I don't think it's accurate to say that nothing at all went wrong here, and we shouldn't pretend otherwise just because POTUS is intemperately tweeting about it and drawing conclusions from it he shouldn't (as I pointed out in my post).

[Matt Burgess @matthewgburgess]

- RCP8.5 is indeed dead and that's a good thing for climate science.

- Technological improvements, and to some extent climate policies, have made RCP8.5 even less plausible, but it was always implausible, for reasons we knew (thanks to @jritch) for a decade and have been widely known since 2020.

- Climate impact research continued to heavily rely on RCP8.5 for years after we knew better, and there are still too many papers making it into top journals with headline findings based on RCP8.5/SSP5-8.5 (or, worse, SSP3-8.5). Reviewers and editors are not pushing back hard enough.

- Many journalists and policymakers have stuck their heads in the sand about RCP8.5 and continue to do so. But there have also been some notable exceptions. E.g., @dwallacewells was one of the first to cover the changing scenario understanding, something I've always admired him for.

- The scientific community *is* gradually correcting course, as evidenced by RCP8.5 being discontinued for AR7, and by all the papers and other materials that led them to that decision.

- Climate change is real and IPCC's Working Group I reports (The Physical Science Basis) are solid. Their conclusions have high overlap with the DOE CWG report, as @RogerPielkeJr has noted.

- Large majorities of Americans want the President and Congress to do more to address global warming, according to consistent polling for the past two election cycles at least.

- There are some bastions of alarmism/bias within climate change academia, but they are largely *not* in the federal civil service. In my experience, most federal climate scientists are hard-working, rigorous (mostly physical) scientists who take their Hatch Act responsibilities for non-partisanship seriously. Gutting NOAA and other federal science is bad for the country (as @RyanWeather and others have argued) and won't save us from alarmism.

- A great way to get to the bottom of how deep the RCP8.5 effect on climate impact science goes and create a more balanced picture would be to convene a new National Climate Assessment, with a broad and viewpoint-diverse author team.

Thank you for your attention to this matter.

[Transition Show @[email protected] @TransitionShow]

In Ep. 275, we review a report from @350 on the cost of delaying the energy transition, and see how the energy transition is helping countries limit the economic damage they are suffering from the global energy crisis resulting from the war in Iran. https://t.co/fVpFpd0sS6

[ty13r @_ty13r]

PSA: Coding agent's can invoke headless instances of each other, so if you're tokenstrapped on your primary subscription try using a Claude as an orchestration agent that issues tasks to Codex and Gemini.

My setup: CC (orchestrator) and gemini & codex on $$20/mo plans. Gemini is hit or miss, Codex is a workhorse.

[Prof. Akiko Iwasaki @VirusesImmunity]

I wrote this piece to promote thoughtful, respectful, and rational engagement with controversial science topics. I hope it fosters constructive dialogue in the scientific community—thank you for reading and sharing 🙏🏼 @NatRevImmunol

https://t.co/iSdbikwy9p

[Matt Burgess @matthewgburgess]

Good to see the IPCC moving on from RCP8.5 and other implausible high-emission scenarios. Climate impact researchers, take note!

Kudos to @jritch for starting the conversation a decade ago.

[Transition Show @[email protected] @TransitionShow]

In Ep. 274, @ember_energy's @nicolasfulghum walks us through all the data in their new Global Electricity Review 2026 report. Renewables are finally pushing fossil fuels off the grid and power sector emissions are declining globally for the first time. https://t.co/1jF6iOSii8

[Transition Show @[email protected] @TransitionShow]

In Ep. 272, @nworbmot shares a new model which shows that by 2030, solar and batteries could supply 90% of electricity to 80% of the global population for less than €80/MWh--cheaper than gas! https://t.co/kQfDgS1V4B

[Anna Wong @AnnaEconomist]

One relatively new reason why high gasoline prices doesn’t bite as hard for households as pre-covid:

2x as many people are now working from home.

[Transition Show @[email protected] @TransitionShow]

In Ep. 272, oil analyst and journalist @Rory_Johnston explains why the Iran war has thrown the world into uncharted territory, with unprecedented high prices ahead. This episode is not paywalled, so enjoy & share widely! https://t.co/i7WzXTKVOa

[Transition Show @[email protected] @TransitionShow]

In Ep. 271, @laurimyllyvirta rejoins us to tease apart the complex picture of China’s energy transition. Listen and learn why China’s total CO2 emissions have been falling for the past two years even while it’s building more coal power plants than ever. https://t.co/7cXAbzVf5X

[Transition Show @[email protected] @TransitionShow]

In Ep. 270 @AdairTurnerUK, co-chair of the Energy Transitions Commission in London, shares with us his wide-ranging, high-level perspective on the energy transition in the UK and the world. https://t.co/WO6wFtIgjS

[Transition Show @[email protected] @TransitionShow]

In Ep. 269, @AriPeskoe rejoins us to review Trump’s attacks on the energy transition in the US and explore the legal options for defending it. Wind farms, solar farms, coal plants, regulations,Venezuela, UN climate bodies, oh my! https://t.co/GMx53QKlbK

[Transition Show @[email protected] @TransitionShow]

In Ep. 268, veteran organizer @CarterLavin joins us to share some of the insights, tactics and lessons learned from his 15 years as a transportation advocate. Listen in and learn how you can help advance energy transition policies in your community! https://t.co/kIeIP6lhqE

[Transition Show @[email protected] @TransitionShow]

In Ep. 267, former IEA Director Nobuo Tanaka shares his perspectives on the global realignment into “petrostates” and “electrostates” and how US policy is pushing Europe and developing countries closer to China. We also discuss evolving Asian grids. https://t.co/WFzi8GBfc7