Rust Never Sleeps / George Morrison🇨🇦

... variability in (effective) annual partitioning of emissions, ENSO and other oscillations, sink trends, etc., there's no way we could confidently detect and attribute that counterfactual, even though it would have represented a massive shift in emissions.

Graph is a poor fit for purpose.

Example:

If, immediately after Oct 2018 IPCC SR1.5 we *had* immediately begun to work towards halving CO₂ emissions by 2030, the cumulative difference to our actual 2018-25 emissions would be ~45 GtCO₂ (true!).

So, total cumulative emissions would be ~2645 vs 2600 GtCO₂.

With all the natural...

ENVIRONMENTAL RESEARCH LETTERS Inherent uncertainty disguises attribution of reduced atmospheric CO2 growth to CO2 emission reductions for up to a decade Aaron Spring, Tatiana Ilyina and Jochem Marotzke Published 24 November 2020

There's also the problem that - despite the strong signal - there's still so much noise in the atmospheric CO₂ dataset that it would take us ~10 yrs to detect and confidently attribute a shift in emissions from say a RCP4.5 to RCP2.6 pathway.

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

1/3

it's set at supply, as in Liebreich's specs. Fossil = Demand - Clean, so (Clean + Fossil) = Supply = Demand.

What both the Liebreich and Ember - Electrotech narrative/modeling makes more clear/real is one part of the dynamic that makes such a functional form for emissions reduction realistic/plausible.

Raupach curve formula in this Environmental Research Letters paper.

... from the so-called "Raupach curves" (example math in this article iopscience.iop.org/article/10.1...) or similar is in the early modeling (at least until close to net-negative gets included). These also are (relatively) slow declines (absolute and rate) early, accelerating later (and then slow).

various modeling assumptions for emissions mitigation that end up with the same cumulative emissions

I'm less concerned with projections for final energy demand growth and more with how the simple models can get people familiar with how a plateau in CO₂ emissions can still belie a great deal of success with cumulative emissions.

If you look at most IPCC emissions mitigation models, some math

Ember Energy / Rystad Energy projection for global final energy demand through 2100.

although, on my X version of Liebreich's model, I mention in the comments the "Electrotech Revolution" work by Ember Energy (also tomorrow's subject on David Roberts podcast), and they have global final energy demand increasing by ~50% through 2100.

ember-energy.org/app/uploads/...

again, true, and every assumption Liebreich makes is subject to countless nuances, etc. but, ultimately, he has global final energy demand slightly more than doubling over next 40 yrs. I think if one presents a model that has materially less than that, it strains credulity at a global level.🤷

This is entirely true, but the "2% annual growth in *global* final energy demand" in Liebreich's *very* simple model setup likely in effect would be compromised of various jurisdictions and sectors with much lower or even zero growth compensating for others with much higher growth.

Thanks!

one last time, the GDP and energy plot

... from IPCC AR6 WGI (Fig SPM.10, iirc).

Volts podcast: substack.com/@drvolts/not...

Liebreich BNEF article Part 1: about.bnef.com/insights/cle...

Part 2: about.bnef.com/insights/cle...

That's about it.

forward cumulative CO₂ emissions

forward additional global surface warming from model's CO₂ from fossil fuels and industry using TCRE of 0.45°C/1,000 GtCO₂

Yes, non-CO₂ and agricultural/land use emissions are omitted. Adjust your own if you want. There are reasons to argue this is pretty close for purposes as well, but, as I say, it's *supposed* to be *simple*.

3. I convert forward cumulative CO₂ emissions to forward temp increases central TCRE...

model estimates for annual CO₂ emissions from fossil fuel and industry

2. I convert fossil energy to emissions in GtCO₂ yr⁻¹ by just multiplying by 37/70 throughout, reflecting the ~2024 emissions from fossil fuels and industry. This assumes - contra historical - no forward improvements in CO₂ emissions/$GDP, but close enough.

same plot in top-of-thread post, showing 2025-66 GDP, Final Energy/Supply, Composition by Clean and Fossil energy.

... the purpose!

About the only things I might want to mention about my implementation:
1. On this plot, (i) energy demand and final energy are assumed equal, (ii) GDP and energy in 2025 are normalized to 100, clean and fossil energy are normalized to initial final energy shares of 30, 70% in 2025.

Liebreich Pragmatic Reset

I am not sure how much time I want to explain the details in my spreadsheet👇 - Michael's explanation two tweets above is so straightforward it takes ~3 minutes to replicate.

Part of its beauty is that it *IS* so simple, over-detailing kind of defeats...

docs.google.com/spreadsheets...

Too slow?

Well, you can spend your time in the real trying to figure out how to speed it up, or spending less time online explaining that the fossil-fuel curves still haven't bent down, and more explaining, why, in your opinion, clean energy can't achieve Liebreich's assumptions

... we can use a very simple model, requiring only a four-line spreadsheet, and explor what happens as clean energy continues to outgrow overall energy demand for a few more decades. Let's start with the global economy, which has been growing at 3.3% per year since the year 2000. Let's assume this continues into the future. Next, we assume that the historic 1.3% average annual improvement in demand-side energy efficiency continues too, leaving 2% annual growtl in demand for energy. We'll be using real energy demand, not primary energy, which is really a measure of supply. Now let's assume clean energy, so renewables, nuclear, and the ambient heat used by heat pumps, start at today's 30% and averages a conservative growth rate of 5% per year over the coming decades, considerably lower than the historic growth rate in renewables over many decades.

Finally, we'll let fossil fuels make up the gap between total energy demand and clean energy provision, as it does in the real world. The first thing our simple model shows is that despite growing faster than energy demand, clean energy is not yet able to meet all the additional demand for energy. But let's run our growth rates out into the future and see what happens. For the next ten years, fossil fuel use continues to grow, falling as a percentage of energy use, but only from just below 70% to just below 60%. Clean energy continues to struggle to meet additional energy demand until 2035. Boo, failure: growth is linear and slow! However, roll the clock another ten years. By 2045, with clean energy continuing to outgrow energy demand by 3% per year, fossil fuel use drops below where it was in 2025, though only by 8%. By now the global economy is using nearly 50% more energy than today, just as all the models say it will, but sourcing less than half of it from fossil fuels. Another decade forward, and by 2055 fossil-fuel use has dropped by 40%, so it is now meeting less than one quarter of energy demand. And by 2065, fossil fuels have been squeezed entirely out of the system.

... assumptions (and I am getting to the assumptions, less so the quibbles) but the beauty of the little model is you can see where you'd want to change the assumptions to get the outcome you want to impose.

Liebreich's assumed 5% yr⁻¹ growth in clean energy supply too fast for you?...

Cumulative Forward CO₂ emissions from fossil fuels and industry, 2025-2066

converting additional cumulative CO₂ emissions to future additional warming, using TCRE estimate from IPCC AR6 WGI Fig SPM.10 of 0.45°C/1,000 GtCO₂

... still yields at net-zero for CO₂ emissions from fossil-fuel and industry by ~2066, and a further increase in global surface temperature from 2025-66 of about 0.58°C, ⬋ and ⬊. Which gets you to, ballpark, 2.0°C since pre-industrial.

Now, easy to find particulars to quibble with in the...

https://about.bnef.com/insights/clean -energy/liebreich-the-pragmatic -climate-reset-part-i/ "Liebreich: The Pragmatic Climate Reset - Part I", BNEF Bloomberg New Energy Finance

as previous post, Liebreich's simple model with GDP, Final Energy Supply and Demand, and Clean and Fossil composition of Final Energy, 2025-66

Converting energy to annual emissions in GtCO₂ yr⁻¹

downthread, I'll include the Google Sheets spreadsheet I made, but it takes about 2 minutes using just Michael's written description in ⬋.

Interesting output: given pretty reasonable/simple assumptions (downthread), a seemingly modest near-term fossil fuel decline ⬊ and ⬊⬊..

Volts podcast of "Michael Liebreich on a 'pragmatic climate reset'" by David Roberts - Substack link https://substack.com/@drvolts/note/p-174079134?r=26ndw

Plot of Liebreich's "world's simplest energy model", all of 4 lines long, here plotting 2025-66 GDP, Final Energy Supply/Demand, and Clean Energy and Fossil composition of final energy

Listening to @volts.wtf recent panel/podcast with @mliebreich.bsky.social , discussing his "Pragmatic Climate Reset", published in two parts at BNEF last September.

Michael mentioned his "simplest energy model ever" - just 4 parameters - and I decided to sketch up and add emissions and temps.

One important finding for me was the overwhelming negative imagery that people have about climate change, when we asked an open-ended question about the first image that came to mind. We're missing positive imagery and narratives about the transition and climate action.

📱Nearly half of US teens say they use the internet “almost constantly.”

😰 Climate anxiety is growing – in one study, more than 45% of young adults said that climate anxiety was impacting their daily life.

Is there a relationship between social media use and climate distress?

new paper on this 👇

cross net zero.

In the case of SSP2-4.5, emissions are still at about 10 GtCO₂ yr⁻¹ in year 2100 (so ~75% decrease from present) but concentrations appear to have already peaked (although plot is cut off at this point).

Box SPM.1 (continued) a) Future annual emissions of CO, (left)

e) CO, concentration (ppm)

Here's some examples.

On the left, various CO₂ emissions scenarios from IPCC AR6 WGI SPM Fig. SPM.5 (a).

On the right, corresponding CO₂ concentration evolutions from IPCC AR6 WGI TS Box TS.5, Fig. 1 (e)

For both SSP1-1.9 and SSP1-2.6, concentrations peak and begin falling before emissions...

... followed by an emissions decline of, say, 3% yr⁻¹, concentrations roll over and begin falling well before 70% declines in CO₂ emissions, iirc. (and I am running this starting at present day atmospheric concentrations).

Anyway, I am going to pull the IPCC plots showing this.

Depends on what you mean by extreme. I am pretty sure each of RCP's 1.9, 2.6 and 4.5 exhibit this, and I think even above that (but somewhat moot for purposes here). Also although there are many models, the simple Bern carbon module, if you run it up to an emissions peak by, say, 1% increase yr⁻¹...

... the models have concentrations rolling over before 70% reduction, but it's a good ballpark for illustration.)]

... to doubting what they *think* they've been told about the relationship between concentrations and temperatures, or the need to continue to reduce emissions if concentrations are already falling at "only" 70%¹ reductions *unless* they've been primed to expect this behaviour in advance. ¹(I think

[by the way, returning to your larger point about the importance of being accurate on the terminology and other particulars of such stock and flow dynamics... the outcome I lay out above presages a point where, at the time, concentrations are falling and temps are rising. the public will be prone...

... net CO₂ emissions hit zero (or negative).

[One can easily see this in the IPCC AR6 WGI (and probably WGIII) in looking at emissions pathways vs concentrations for the same RCP... concentrations roll over and begin declining before the year net zero emissions is achieved.]