There’s a very old joke I’d like to share with you, and it goes something like this:

A man is found repeatedly firing an elephant gun in the local park. “What are you doing that for?” he is asked. “It’s to scare away the elephants”, he opines. “But there are no elephants in this park”, comes the reply. “See,” he smiles, “it’s working already”.

Now, if you were to believe the man with the elephant gun, what you would be dealing with here is a perfect example of what is known as the Preparedness Paradox (sometimes ‘Preventative Paradox’). It is a paradox in which the removal of a problem is misinterpreted as evidence that the problem never existed in the first place. It’s an argument that has been made many times before in real-life situations. Take, for example, the Y2K or Millennium Bug. Widespread faults in date-handling code were thought to pose a significant threat, leading to a global IT initiative to find and correct the bugs in order to avert disaster. As it happens, the new millennium dawned with very little drama, causing many to declare that the whole thing had been hyped. Not so, said the IT managers. According to them, what we had witnessed was a classic case of the Preparedness Paradox. Similar arguments have been made regarding the necessity for lockdowns during the Covid-19 pandemic. A lockdown that avoids a surge in numbers invites the interpretation that the threat analysis had been flawed all along.

I don’t want to get drawn into a Y2K or Covid debate here, other than to point out that the reason why the elephant gun joke is supposed to be funny has nothing to do with the Preparedness Paradox. Instead, the humour stems from the alternative interpretation, i.e. there never were any elephants to scare away. So, with that interpretation in mind, I want instead to reflect upon RCP8.5 and the IPCC’s recent withdrawal of the scenario as a plausible worst-case upon which to formulate climate policy. Could it be that those who see this as a belated admission that it was always an implausible scenario are actually guilty of falling for the Preparedness Paradox? Did RCP8.5 really do a great job of scaring off elephants, or were there never any elephants to begin with?

The Case for the Elephant Gun

As I’ve just explained, decisive action has the disadvantage that it completely erases the visible evidence that it was ever needed. Many mainstream climate scientists are adamant that this is exactly what has happened in the case of RCP8.5 and that its recent removal belongs firmly in the Preparedness Paradox category. The premise is that when RCP8.5 was conceived in the late 2000s, global emissions were tracking aggressively upward. The scenario was never intended as a ‘business as usual’ scenario but a plausible stress-test deliberately used to map out the severe risks of a completely unmitigated fossil-fuel-heavy world. Supporters argue that the alarm raised by modelling RCP8.5 directly led to global treaties (like the Paris Agreement), national carbon mandates, and massive state subsidies for green energy. In this view, the measures were necessary and the resultant actions have flattened the curve, thereby causing the demise of RCP8.5’s plausibility. This is seen as a triumph of proactive global policy. It is a textbook Preparedness Paradox: the potential disaster described by RCP8.5 disappeared because the warning was successfully heeded.

The Case for Non-Existent Elephants

Critics, such as policy analyst Dr Roger Pielke Jr, argue that the flattening of the emissions curve is irrelevant because RCP8.5 was always built on highly unrealistic, extreme assumptions. Yes, it was a stress-test but it was never a credible one. As Justin Ritchie and Hadi Dowlatabadi demonstrated in 2017, for RCP8.5 to occur, the world would have to undergo a massive, unprecedented return to coal. The model required a five to eight-fold expansion of global coal use by 2100, involving the liquidating and burning of coal reserves that do not physically exist in extractable forms. In addition, it required the somewhat bizarre economic assumption that when oil ran out humanity would convert coal into liquid fuel for cars rather than using newer and cheaper alternatives. It is also worth noting that global coal use actually peaked around 2013 (long before major global climate policies like the Paris Agreement could even take effect), and so the RCP8.5 trajectory was impossible from the start. Whilst the downturn in coal use has been reversed by recent events, there is still not the slightest indication that the growth in usage necessary for RCP8.5 to regain any credibility could possibly materialise. Therefore, claiming that the RCP8.5 scenario had been averted by the measures it inspired is akin to the firing of an elephant gun in a public park many miles from the Serengeti.

The Greatest Pity

The debate boils down to who is pushing the historically accurate narrative. If the extreme scenario was an artificial, fundamentally flawed baseline then the policies justified by it were always built on what would ultimately prove to be a modelling error. Furthermore, it was an error that carried with it huge costs that could never be justified. If, on the other hand, the scenario was a perfectly possible trajectory that was actively averted by decades of climate activism and policy shifts (the Preparedness Paradox), then the logic holds up and those very real elephants have now fled.

Which side you take in this argument depends upon how one chooses to read the room, and so I’ll leave it to my readers to form their own opinions. However, I have to declare that my sceptical orc genes predispose me to take the side of those who believe that RCP8.5 was never plausible as a stress-test in the first place. Consequently, no matter how much one might argue that the curve has been flattened, such flattening can’t have altered the status of RCP8.5.

The greatest shame, however, is that RCP8.5 was not only an implausible stress-test from the outset but was also mis-sold by many as a business-as-usual scenario, fuelling endless doom-laden predictions that have led directly to environmental security theatres such as the UK’s Net Zero debacle. In engineering, an extreme boundary case is used to find a system’s breaking point. It is never meant to represent the expectation. By branding RCP8.5 as “business-as-usual” in thousands of peer-reviewed papers, climate scientists and activists perfected the measurement of a purely fictional environment, leading to a massive misallocation of academic effort and wholly inappropriate regulatory initiatives.

So, no I don’t believe the retirement of RCP8.5 is a story of policy triumph; it is a story of belated scientific adjustment. Yes, a worst-case scenario has its purpose in risk management insofar as it creates the boundaries within which mitigation policies have to operate. However, to achieve that purpose, the posited worst-case has to have credibility, and I don’t believe that was ever the case in this instance. The implausibility of RCP8.5 should have been admitted long ago. The scenario didn’t become implausible because the world changed; the world simply continued to operate within physical limits that the scenario had always chosen to ignore. Sooner or later, reality bites and I don’t think that RCP8.5’s demise has come a moment too soon.