NN#7: A New Climate Catechism

According to legend, on October 31, 1517, Martin Luther nailed a copy of his “95 Theses” to the door of the Wittenberg Castle church in Wittenberg, Germany. It was a list of questions and propositions for debate, delivered in an academic fashion, questioning the commonplace practice of the day in which the Church sold “indulgences” relieving penitents of the punishment for their sins. Luther, building upon Augustine, believed that salvation comes by God’s grace through faith, rather than through human deeds, and objected to the practice. His arguments eventually fractured the Catholic Church and helped to launch the Protestant Reformation. The new Protestant denomination believed that ordinary people could have a direct relationship with the Divine, without mediation through clergy.[i]

On July 20, 2026, Dr. Emily Grubert, an Associate Professor at Notre Dame University in Indiana, published a perspective piece in the journal Environmental Research Letters that had a similar resonance, at least for me. Whether it leads to a Reformation of energy and climate research remains to be seen, but I hope it does, because that priesthood is overdue for a shakeup.

Like Catholic doctrine of the 16^th century, which over centuries had become an accretion of theological refinements, devotional practices, and institutional traditions that obscured the Gospel, energy and climate science has become a sprawling thicket of its own accumulated concepts, an untended garden where the desirable specimens are all but buried beneath a thick mass of weeds. Lord help the climate penitent who would wade into that canon in search of clear guidance.

In fact, it was only after many years of studying the body of climate science and trying to understand what it says and how it works, that I finally realized the stunning truth: Honest researchers, who are genuinely doing their level best to get their work right, developing tens of thousands (maybe hundreds of thousands) of careful, detailed models, and doing millions of model runs using different parameters, employing the most extensive data sets and sophisticated computer programs and powerful computers available, are not even trying to produce a model that actually tries to predict, accurately, what the likely course of the energy system—the biggest determinant of climate—will be in an age of climate change. Not one.

That’s not what energy and climate modeling is for.

How modeling works

What the models are designed to do, broadly speaking, is to answer what-if questions. To explore the range of outcomes that might obtain under various assumptions. They use scenarios to try to capture the complexity of how systems might evolve. Some of those scenarios might be labeled as “business as usual” or “reference” scenarios, and those scenarios are often misinterpreted to be projections designed to paint a probable future. But they are not. They’re just scenarios, with no probabilities assigned.

So many scenarios. None of which are ever labeled as “likely” or “probable.”

That works well for modelers. If your scenario turns out to be unrealistic, no big deal. It’s just a scenario. And if your scenario turns out to be accurate, you get some credit. It’s all reward, and no risk.

But if are a policymaker, or a layperson, and not a modeler of climate or energy systems, what you really want to know is what’s going to happen.

I’d argue that’s all that anybody outside of the modeling community really wants to know.

So the one scenario that everybody actually wants to understand—the one that is likely to happen—is the one that no modeler wants to produce.

There is a long and convoluted history of how climate modeling got the way it is, and here I am mainly referring to the suite of Representative Concentration Pathways (RCPs), Shared Socioeconomic Pathways (SSPs), and Integrated Assessment Models (IAMs) used in the framework developed by the United Nations’ Intergovernmental Panel on Climate Change (IPCC), which are then used to simulate the physical climate in Earth System Models (ESMs) or Global Climate Models (GCMs). (There are other modeling systems and frameworks for climate and energy analysis, but nobody uses them to tell us what’s likely either.)

Over the years, I attempted to distill this complex framework and methodology down for a lay audience in our climate science miniseries on the Energy Transition Show, so you can explore that if you want to learn more about it. For a single-episode summary, try Episode 51. Many of the other episodes in that miniseries delve into the disconnects between the modeling world and the real world.

If you are a climate scientist, and you’ve been trained up over many years of study within it, the IPCC framework makes sense. There are good reasons for why it has evolved the way it has, and the results of that work are, by and large, trustworthy—at least for the objectives they were designed to achieve.

But giving the world accurate guidance on how the global energy and climate systems are likely to evolve, given all that we know about how those systems, isn’t actually one of those objectives.

I know. It’s crazy. Mind-boggling. I had to keep asking the scientists myself: Really? Amid these millions of model runs, there isn’t one that attempts to project what is actually going to happen to us? It seemed unfathomable.

But there isn’t.

There definitely could be. I don’t think there’s anything standing in the way of it other than reputational risk. But that’s enough to scare everyone off, apparently.

I have wondered if “gamifying” it—turning it into a contest—would encourage a few modelers to give it a whirl. Or offering a prize for the most accurate model. Sadly, I have not the resources to organize such a contest myself.

Now, I don’t want to seem unsympathetic. I am fully aware—more than most—of how complex the world is and the innumerable factors that affect how the global energy system is evolving. I have studied many, many energy models in the more than 20 years that I’ve been studying energy, and none of them came close to predicting the world we have today. It’s wickedly difficult to model. Probably impossible, actually. It’s much easier (and defensible) to model a small set of factors within the established bounds of a scenario that at least has a chance of being accurately quantified. That’s why everyone does it.

But it’s not actually a good excuse for not even trying to tell us what we really want to know.  

An empirical approach

There is one approach that seems to me to be at least going in the right direction, and that’s the one that Doyne Farmer and his colleagues at Oxford University are using. I delved into a few of those iterations on the Energy Transition Show, in Episode 159 with Matthew Ives and Episode 239 with Farmer himself. What’s different about that approach is that they start with historical data on how the energy system is evolving, calculate the observed rate of change for various technologies, and then use that to project forward how they might evolve. The chief advantage is that it’s based on empirical data about the world as it is, instead of being based on hypotheticals or policy. Were there funding to support it, I think their agent-based modeling platform could produce some really useful projections about how the global energy system might actually evolve, and therefore, the climate.

That kind of bottom-up approach, starting with the emissions of the energy system and then using that to calculate their effect on the climate, always seemed like the obviously sensible methodology to me, but it was abandoned years ago because it was moving too slowly. (Again, see Episode 51 for more on that history.)

The RCP8.5 wars

The abstraction of climate scenarios from energy scenarios is the original sin, if you will, that resulted in the most extreme warming scenario, known as RCP8.5, becoming widely referred to as “business as usual,” which in turn led to all sorts of wild projections about extreme global warming effects. As we explained in Energy Transition Show Episode 49, it was never intended to be used that way. Without getting too wrapped up in the many details, it was originally designed to represent a world where global oil supply was running short, and the world turned to producing liquid fuels from coal to fill the gap. It imagined a world in which global coal consumption increased by roughly a factor of ten between 2000 and 2100, resulting in 8.5 W/m² of radiative forcing, 5°C of warming, and all sorts of hair-raising apocalyptic climate scenarios that generated years’ worth of terrifying headlines.

But much of the world has been phasing out coal for years now, and that nightmarish coal-to-liquids scenario is not only wildly unlikely; it now seems quaint, given how the global energy system has evolved since a team of researchers at the International Institute for Applied Systems Analysis (IIASA) developed it over 15 years ago. It hasn’t been a “likely” scenario for over a decade now. But because no probabilities have ever been assigned to any of the scenarios, it has been misrepresented as a “business as usual” (meaning plausible) scenario in hundreds of scientific papers. We explored that debacle with Michael Liebreich and climate modeler Nico Bauer in Episodes 116 and 117 in 2020. Even after it was proved to be unlikely, some have clung to it as a worst-case outcome for a wide range of hypothetical futures unbounded by reality.

Which is exactly why President Trump was able to triumphantly declare that it was “WRONG! WRONG! WRONG!” and use it as a cudgel to inveigh against the IPCC and climate modeling in general when RCP8.5 was removed from the ensemble used in the next major iteration of climate models in a paper published in April 2026 and led by one of its principal investigators, Detlef Van Vuuren. A pair of articles co-authored by climate scientist Zeke Hausfather—one on his own blog and one at one at Carbon Brief—offer a useful history and perspective on the scenario, both of which are linked into the show notes.

So RCP8.5 has been an absolute disaster from a climate messaging standpoint. And I must head off the chorus of complaints right here, because during the “RCP8.5 wars” that transpired in various blogs and social media (mainly Twitter) circa 2000, I heard all the arguments about why some modelers found it useful and think it still has a place in the canon. So please spare me the recitation. Suffice it to say that had a probability been attached to RCP8.5 all along, and adjusted as time went on and the global energy system evolved, we might have had far more useful public education on climate with a lot less unproductive doom-mongering about a vanishingly unlikely scenario.

I’m not terribly interested in that debate. My objective has always been merely to try to understand what’s likely to happen and convey that to the public.  

Explicit content ahead

The obvious corollary to that objective is understanding what must happen in order to avoid climate doom. Which brings us back to Emily’s piece.

The problem, as she explains, is that “limited scholarship focuses on solving the physical, institutional, and managerial puzzles of successfully phasing out fossil fuels globally.” Instead, researchers go out of their way to explore scenarios with “some kind of abatement measure that allows for ongoing fossil fuel use, like carbon capture and storage (CCS) or compensatory carbon dioxide removal (CDR),“ instead of explicitly centering and advocating for phasing out fossil fuels (almost) entirely.

Maybe that’s just down to climate research realpolitik. Nothing wrong with that, I suppose, so long as it’s just an occasional leavening agent in a body of work that otherwise seeks to repeatedly, unrelentingly, hammer home the point that fossil fuels must go.

As she concludes, ever so politely [emphasis mine]:

Scholarship has clearly demonstrated that climate change is harmful, fossil fuels cause it, non-fossil alternatives are viable, and fossil fuel abatement or offsetting is hard and risky. What is needed is an explicit, rather than implicit, acknowledgement that fossil fuel phase-out is the dominant strategy for addressing climate change. Are there edge cases where fossil resources might still be used, particularly in non-fuel settings? Probably. But it is unusual that practical, policy-oriented, rigorous research should focus most directly on edge cases to the exclusion of the dominant strategy. ERL’s excellent, engaged community of researchers has the skills and the courage to say what we mean, and to address the important questions: a just, effective energy transition requires, at minimum, near-total fossil fuel phase-out. May the next decades of ERL scholarship take this point head on, and produce rigorous, actionable, equitable, and targeted research on how we do it.

But that’s not the body of work we have today. What we have today is a massive pile of what-ifs and caveats and unlikely edge-cases that protect the researcher from criticism and offer the policymaker little in the way of actionable intelligence.

I may have stretched Emily’s message beyond what she intended it to say here, and I don’t pretend to speak for her. But we have to do better. We have to have the courage to try to tell the world not only what’s likely to happen, but what they have to do to avoid climate doom, as plainly and clearly as possible. It’s so obvious that I’m shocked and horrified that it even needs to be said.

As I mused in “Nelder Notes #4 – Carbon Capture Follies,” we’ve had several decades now of malinvestment in CCS and CDR that haven’t even budged the carbon concentration needle. There is no point in continuing to pretend like they’re real solutions. They’re just sops to the fossil fuel industry and its assets in government. They are indulgences peddled by the climate priesthood to assuage the guilty consciences of climate criminals who hope to dodge divine judgment. Continuing to talk about them as if they are realistic and likely paths forward is a sin in itself, because it obscures the fundamental truth of the climate gospel: Fossil fuels must go.

Nail that to the church door. Yell it from the rooftops. Let not another research paper abstract go by that fails to put it front and center. Then go forth and sin no more.

And if you can prove me wrong—if you actually do have a model that you think captures a likely future of the world that we have now, where solar and batteries are quickly dominating the growth of the global energy system and everything that can be electrified is being electrified? By all means, send it to me at suggestions@transitiontimes.net I may give it a shout-out in a future post.  

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[i] Although I was raised in the Protestant church, I am not a theologian. I am mainly summarizing here from History.com. If you want to quibble with my deliberately brief summary of this long and complex historical movement, just bear in mind that it makes no difference to me and that my only intention here is to use it as allegory, not to teach history or theology.

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Sources 

Emily Grubert’s personal website

Emily Grubert, “The state of energy transition research and the need for fossil phase-out: evidence from Environmental Research Letters,” Environmental Research Letters, Vol. 21, No. 14, July 20, 2026. DOI: https://doi.org/10.1088/1748-9326/ae8610.  

Van Vuuren, D. P., O'Neill, B. C., Tebaldi, C., Sanderson, B. M., Chini, L. P., Friedlingstein, P., Hasegawa, T., Riahi, K., Govindasamy, B., Bauer, N., Eyring, V., Fall, C. M. N., Frieler, K., Gidden, M. J., Gohar, L. K., Högner, A., Jones, A. D., Kikstra, J., King, A., Knutti, R., Kriegler, E., Lawrence, P., Lennard, C., Lowe, J., Mathison, C., Mehmood, S., Nicholls, Z., Prado, L. F., Zhang, Q., Rose, S. K., Ruane, A. C., Sandstad, M., Schleussner, C.-F., Seferian, R., Sillmann, J., Smith, C., Sörensson, A. A., Panickal, S., Tachiiri, K., Vaughan, N., Vishwanathan, S. S., Yokohata, T., Zecchetto, M., and Ziehn, T.: The Scenario Model Intercomparison Project for CMIP7 (ScenarioMIP-CMIP7), Geosci. Model Dev., 19, 2627–2656, https://doi.org/10.5194/gmd-19-2627-2026, 2026.

Zeke Hausfather, Glen Peters, and Piers Forster, “On the death of RCP8.5,” The Climate Brink, May 18, 2026.

Robert McSweeney, Cecilia Keating, Zeke Hausfather, “Factcheck: Trump’s false claims about the IPCC and ‘RCP8.5’ climate scenario,” Carbon Brief, May 19, 2026.