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Barry Brill

RCP 8.5: A recipe for endless waste

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The climate system is a coupled non-linear chaotic system, and therefore the long-term prediction of future climate states is not possible. Rather the focus must be upon the prediction of the probability distribution of the system’s future possible states …     – Intergovernmental Panel on Climate Change

A lot of pipes are in our future. With the overdue requiem of the ‘3 Waters’ hustle, we now have civil engineers all over the country planning and costing out thousands of kilometres of new ‘sustainable’ water pipes and systems.

The Labour shadow minister, Kevin McAnulty, tells us “We’re talking about $185 billion that needs to be spent on water”. What?  How could it cost that much?

KiwiRail says much of the cost blowout for replacing Cook Strait ferries was due to portside infrastructure having a 100-year resilience life, rather than a 20-year design life. Really?

In “Infrastructure omnishambles a matter of national shame”, Tova O’Brien speaks of ‘an almighty wallop to our wallets’ – pointing out that other countries do it better and cheaper.

One reason that construction of everything costs more in New Zealand is because we are ‘the shaky isles’. But that’s just a fact of geography and we can’t do anything much to change our seismic profile.

What we can do something about is the “safetyism” of our public servants, who tend to grossly over-state risks and persistently regulate for gold-plated specifications. They have perverse incentives – while there’s plenty of downside whenever something goes wrong in future, there’s no upside for them in helping to keep the construction costs down now.

Perhaps the worst instance of this bureaucratic ultra-conservatism is to be found in the Ministry for the Environment’s “Guidelines” (read ‘rules’) for Rolls-Royce-standard resilience against the possible future impacts of climate change. Here are a few of them:

Coastal hazards and climate change                       Long-term insights briefing 2023

Our atmosphere and climate                                    Atmosphere and climate indicators 2023

NZ Climate Change Projections.                              Interim guidance on sea level projections

Preparing for coastal change.                                  Planning for coastal adaptation

National climate change risk assessment                National Adaptation Plan

The problem?  Every one of these key documents is seriously misleading and provably wrong. 

Not one of them attempts to assess the actual likelihood of the threats that they assume to lurk in our future.  Unbelievably, they treat 1% risks and 70% risks as if they were identical.  

Tailrisk Economics has published a scathing review of the National Climate Change Risk Assessment 2020., which found the average evidence quality score to be a scandalously low 3.09 out of 10. In another post, Ian Harrison calls it “A Case of Science Denial”.

The pervasive errors are not random – they all grossly overstate the forecast impacts of guesses regarding future extreme weather events, such as floods and droughts and storms.  And then they accumulate these  relentlessly over many decades into the future, without any regard to technology and policy changes over time.

These systemic exaggerations translate into hundreds of millions of wasted spending of scarce ratepayer/taxpayer dollars in every region.

Over-wide stormwater pipes, over-high wharf piles, over-built sea walls, indestructible power pylons, re-routed highways, restrictive zonings, refused resource consents, unnecessary migration of coastal homes, etc.

The great majority of the Ministry’s false prophecies are based on a single imagined storyline – RCP8.5 – an obsolete 15-year-old scenario which is now almost-universally recognised as being highly unlikely, if not wholly impossible. Its probability distribution is about 1%.

RCP8.5 rests on assumptions that global emissions are sharply increasing, that no country anywhere has ever or will ever adopt a climate policy, that the world’s population will double and that coal-power will be dominant by 2100. All this is plainly nonsense.

Yet the NIWA’ website continues to describe this as its “business as usual case” – ie the most likely outcome, unless the world’s current trajectory is changed. And NIWA is the Government’s principal climate science adviser.  

Intelligent guesswork

The UN Climate Panel (IPCC) tells us the “probability distribution” (ie likelihood) of global warming by 2100 depends upon the aggregate volume of human greenhouse gas (GHG) emissions over the next 80 years.

But how can anyone predict that?  Who knows when China’s emissions will peak, and how fast they will decline (if at all) during the 2060s?  Or India?  Or Indonesia, Russia, Brazil, etc?

The actual volume will turn upon the characteristics of as-yet-unknown technology changes, as well as millions of unknowable human decisions over future decades. So, we are left to guess. While the chances of our guesses being close to actuality are extremely low, they can obviously be improved somewhat if our guesswork is ‘educated’ and intelligent.

Unfortunately, the track record of previous forecasts in the climate change sector is nothing short of appalling! Many thousands of guesses (allegedly ‘educated’) have proved to be flat out wrong – ranging from the “global cooling” media scare of the 1970s to Al Gore’s 2008 claim that the Arctic would be “completely ice-free within five years”.  A US blog Wrong Again” sets out actual newspaper clippings of outrageously misleading climate predictions over 50 years.

Most planners believe the most intelligent way to guess at the future is to carefully identify the relevant existing trends and then project them forward in time. In relation to aggregate GHG emissions, the 30-year trends are that the aggregate annual volume is increasing but the rate-of-change is falling. And the 10-year trends are the same. So, any ‘educated’ guess would project that annual increments would flatten out over the next decade and then steadily decline.

The IPCC – no opinion

About 15 years ago, the IPCC climate scientists (WG1) declared that they had no opinion on the future path of GHG emissions. They rightly disavowed any expertise in this sphere, as future emission volumes have nothing to do with atmospheric physics or allied specialties.

Instead, the Panel reported on four hypothetical alternative warming pathways – two baseline cases (4.5 & 6.0) bracketed by two outer extremes (2.6 & 8.5) – to represent the huge range of possibilities mentioned in 20 years of scientific literature. The respective pathways are based on incompatible assumptions so only one can be right. It is left to each policymaker (ie non-scientists) to make their own decision as to which scenario seemed most likely.

International Energy Agency – firm opinions

The International Energy Agency (IEA)  has recently published the following four pathways with  their associated emission levels:

Predicted global warming relative to 1850-1900[1]

Warming by 2100 Scenario Net Zero Emissions RCPs SSSP
1.4°C NDCs are sharply increased, CO2 is removed from atmosphere with NETS By 2030 1.9 1–1.9
1.8°C All NDCs are fully met. By 2050 2.6 1–2.6
2.7°C 2023 climate policy settings remain unchanged. After 2100 4.5 2–4.5
4.4°C All climate policies are reversed. Population and coal usage soar. No technology change Emissions

triple by 2075

8.5 5–8.5

This Agency is the sole authoritative international source for estimating future global emissions[2].

It is comprised of economists/planners/technologists/energy experts/engineers/futurists who make their living from discerning and projecting behavioural and other trends. It has unparalleled access to the actual data of their 31 members and 13 associate countries, which together make up 75% of total world energy demand.

The IEA publishes the annual World Energy Outlook (WEO) which includes extensive analysis and advice for policymakers around the world. As shown above, the latest WEO (October 2023) forecasts that aggregate GHGs over the next 80 years will be somewhere between the low baseline case (RCP4.5) and the extreme low case (RCP2.6). It virtually ignores the two high scenarios (6.0 and 8.5) and adds a new ultra-low scenario (1.4) instead.

It is immediately obvious that the extreme high storyline (RCP8.5) is now completely out of the question. It could never plausibly re-enter the picture unless the world in general were to switch its collective goal by 180° from “net zero” to “net maximum”.

As I see it, the only way that could possibly happen is if the next Ice Age (glaciation) were to begin in the next few decades – and the chances of that are estimated at less than 1%.

Too often, New Zealand planners and engineers ignore the core requirement to select one of the opposing scenarios and ignore the rest. Instead, they bundle them all together and then base their analysis on the “worst case” of 8.5.  Consequently, there is a better than 99% chance that their forecasts will turn out to be completely and expensively wrong.

A long-running fraud

RCP8.5 was intended from the outset in 2009 to be an extreme outlier scenario, with an original likelihood of less than 10%.  During the following decade, with the rate-of-change of global emissions dwindling year by year, its objective status moved from unlikely to near-impossible. Curiously, at the same time, 8.5 was being used more and more frequently in the scientific literature as a baseline case.

We now know that the integrity of 8.5 was being deliberately destroyed behind the scenes by a well-funded but deceitful lobbying campaign in the USA. A 2020 Forbes magazine article explains in detail how three billionaires (two of them 2020 presidential candidates – Bloomberg and Steyer) successfully conspired to reposition the 8.5 pathway as being “the business-as-usual baseline scenario”. I encourage readers to read the whole article (it is not paywalled).

The author, Professor Roger Pielke Jr, notes: “This is a story of how wealth and power have corrupted science in pursuit of political goals”.

In light of this public exposure, which understandably went viral, it beggars belief that NIWA not only swallowed this corrupted science but remains stubbornly clinging to it, even to this day.  

The Silent Reset

For 33 years (from 1988 to 2021) the consensus climate science orthodoxy was that anthropogenic global warming (AGW) up to 2100 would be at least 4°C – and maybe as high as 6.5°C. These figures, all based on gross over-estimates of future emissions, were the foundation  of all the “existential threats” and other scare stories that dominated corporate media coverage.

The 2021 WEO then shocked climate scientists by projecting out-of-the-blue that the world average temperature by 2100 would “most likely” be less than 3°C, even if no further mitigation policies were adopted. Nobody outside the scientific world seemed to take much notice, perhaps assuming it was just a blip. There were no front-page headlines. 

Then the 2022 WEO report expanded on the issue, refining its forecast to 2.5°C by 2100 – an estimate that was fully endorsed in the Emissions Gap Report 2022 a 132-page analysis by the UN Environmental Programme (UNEP).

The reaction to these 2022 reports led me to post “The overdue retraction of a giant lie a little over a year ago – along with three supporting posts that appeared here. This new outcome of only 2.5°C was the answer to 30 years of prayers!

Warming of 2-3°C equates to radiative forcing of 3-4 Watts per square metre. As will be seen from the table above, these new IEA projections mean that the extreme pathway of 8.5 W/m2 is now right out of the frame. That is why both the IEA and UNEP omitted it entirely from their annual reports in 2022 and 2023.

But there are still no headlines in the corporate media. Obviously, a huge amount of both political and monetary capital has been invested in those pre-2021 warming estimates (ie in 8.5) – and there is an equally large reluctance to write off that capital. 

The UN Panel

Given the reset by other UN agencies, the IPCC has been criticised for even continuing to report on the 8.5 and 6.0 scenarios in their Sixth Assessment Report (AR6). This is a bit unfair.

The purpose of AR6 was to analyse and report on scientific literature published between 15/03/2013 and 30/09/2020. During that period, research papers were dominated by the high-end scenario – not least because of its fraudulent promotion by billionaire politicians. It would, of course, have been hugely controversial to omit or moderate all that material.

It is also significant that the journal papers that have done the most to discredit the 8.5 pathway (eg Hausfather (2020) and Ritchie (2021)) appeared subsequently. And neither the IEA nor UNEP had reset their forecasts by 2020

It seems highly unlikely that 8.5 will survive beyond AR6.  Professor Jim Skea, the incoming chair of IPCC, has indicated his personal scepticism and says that global emissions will fall rather than rise during the rest of the century (emissions peaked in 2013).

In June, a CIMP7 working group has already recommended that RCPs be dropped and that the future focus should be on emissions-driven climate modelling rather than concentration-driven modelling.

Was the Minister Misinformed?

On being asked by Stuart Smith MP whether he agreed that 8.5 was no longer an appropriate modelling scenario, Climate Change Minister James Shaw responded (PQs 43864 & 44198):

RCP6.0 and RCP8.5 are high emissions scenarios that reflect where we could be if we have the global emissions reductions policy settings that we have in place right now. They are the worst-case scenarios but are still possible if the current global emissions trajectory continues.                   [Emphasis added]

That reply is flat wrong. In drafting it, the Ministry must have relied upon the “corrupt science” pedalled by NIWA.

New Zealand has been funding the IEA since 1977, presumably because it values its research and advice on international probabilities.  The key finding of its 2022 WEO report (as well the UNEP report) was that ‘the policy settings that we have in place right now’ bring about a pathway around 3.2W/m2 and NOT 8.5W/m2 (and consequently 2.5°C of warming rather than 4.4°C of warming).

As shown above, WEO 2023 reports on three scenarios:

  1. Stated Policies based on current policy settings: 4°C by 2100
  2. Announced Pledges based on full implementation of all promises:
  3. “Net Zero by 2050” worldwide: C

… or Playing Politics?

It’s hard to believe that neither the Minister nor his Ministry was aware of what the rest of the world is doing. Even the Biden White House has now abandoned the 8.5 pathway, as Professor Pielke reports. “Now let’s update all the research and policy still based on Zombie science” he says.

But it sometimes suits the Government’s purposes to cling to zombie science – especially gross over-statements – as we saw in regard to methane in “The Ministrys Mammoth Greenwashing Scam” Fear-mongering and hyperbole was the cornerstone of every aspect of Minister Shaw’s climate policy – regardless of cost or consequence.

The Ministry must also be aware by now that the original pathways were politically manipulated; that several seminal journal papers, including Ritchie & Dowlatabadi (2017), have demonstrated that the coal-intensive scenario is no longer believable;  and that the UN and IEA have distanced themselves from it.

Cognitive Dissonance

Our Government assures us that it will achieve “Net Zero emissions by 2050” so global temperatures can be held to a maximum of 1.5°C. Other countries representing 90% of global GHGs have also set targets to reach net zero emissions within a few decades. OECD governments even say that the 1.5°C aspiration is credible and achievable.

At the same time the New Zealand Government urges Councils and other policymakers to base their policies upon the assumption that worldwide emissions will not decrease but will likely quadruple and that global temperatures will soar to 4.4°C or more.

They can’t have it both ways. Cognitive dissonance is the unpleasant emotion that results from holding two contradictory beliefs or behaviours at the same time.

Probable or Possible?

The Minister’s PQ response (above) contains another worrying assertion:

Using these scenarios in planning processes and for risk and hazard assessments ensures that we are making good, robust decisions for a range of potential outcomes, all of which are plausible.

It should never be the aim of planning processes to cater for a forecast that is merely “possible” or “plausible”. Almost everything falls within that near-infinite range. The core purpose of risk management is to repeatedly narrow the options so as to determine the “most likely” case.

A local body engineer once told me that flooding infrastructure should cope with “the worst case scenario”, ie a 1-in-10,000-year flood. That is utterly absurd and merely ensures that either the Council or the ratepayers will be bankrupt after their first gold-plated Rolls-Royce project.

This focus on possibilities rather than probabilities also permeates this Minister’s “Climate Change Risk Assessment” report which deals at length with just how bad a range of threatening events might possibly become, while saying nothing at all about how likely they are to ever happen at all.


I’ll give the last word to Professor Pielke:

I’m not going to mince words — In 2023, giving RCP8.5 official governmental status is scientific and policy malpractice. It will lock-in the use of an implausible climate scenario for the rest of the decade, even as climate experts know better.

I can’t say I really understand this — we all should want governments to use the best available and most up-to-date understandings to guide decision making. Perhaps there is a concern that resetting our thinking on scenarios will result in major changes in how we think about climate and climate policy, as the reliance on extreme scenarios has been a staple of climate politics for decades.

But make no mistake, change will come. Just not yet.


[1] Taken from IPCC Figure 8.1 SPM WG1 AR6, and Wikipedia Table

[2] John Kerry, the US’ top climate diplomat, says that the IEA “is now probably the principal arbiter or referee about many of the things we need to be thinking about with respect to our policies”.