The new RCPs are not projections, probabilities, prophecies or pathways – they might possibly be potentialities.
Guest essay by Barry Brill
The IPCC begins with science:
“In sum, a strategy must recognise what is possible. In climate research and modelling, we should recognise that we are dealing with a coupled non-linear chaotic system, and therefore that the long-term prediction of future climate states is not possible.”[1]
For its third and fourth assessment reports, it relied upon SRES scenarios or storylines in lieu of predictions:
‘Futurology’ – the study of postulating possible, probable, and preferable futures and the worldviews and myths that underlie them. There is a debate as to whether this discipline is an art or a science[2]” says Wikipedia.
The fifth assessment has moved on to pure hypotheticals in the form of Representative Concentration Pathways (RCPs):
“Four RCPs were selected and defined by their total radiative forcing (cumulative measure of human emissions of GHGs from all sources expressed in Watts/m2) pathway and level by 2100. The RCPs were chosen to represent a broad range of climate outcomes, based on a literature review and are neither forecasts nor policy recommendations[3]”.
RCPs start with some conjectures about 2100 outcomes, and eventually aim to work out “pathways” back to the present day. The storylines have not yet been written, but the IPCC is co-ordinating extensive modelling work to develop “Shared Socioeconomic Pathways (SSPs)” with suitable narratives tying the SSPs to the RCPs.
This “working backwards” stratagem has previously worked quite well for the IPCC, where the Summary for Policyholders (SPM) is published first and then the peer-reviewed science is amended to fit. Now the climate outcomes are written first, and the ‘futurology‘ is later devised to fit.
Unlike the SRES of AR4 there is no suggestion that the RCPs are “projections” – which the dictionary describes as[4] as “an estimate of what might happen in the future based on what is happening now” and “an estimate of future possibilities based on a current trend”.
So RCP climate outcomes in 2100 are not forecasts or predictions or projections. Nor are they (yet) potential pathways.
What can they be? Could they be described as prophecies or soothsayings – or maybe even wishlists?
It must be remembered that the IPCC has been careful not to claim that any of the four RCPs are probable, or even slightly more likely than an infinity of alternative future possibilities. In a SMP that offers percentage likelihoods in most paragraphs, confidence levels for RCPs are conspicuously absent.
The “representatives” were evidently chosen quite arbitrarily and aimed only at ensuring a good spread. Back in 2000, the SRES Scenarios “represented the full range of driving forces and emissions excluding only the outlying “surprise” or “disaster” scenarios in the literature”. The range of the RCPs is much wider, covering the entire span of the scenario literature, inclusive of outliers. In addition, each RCP includes provision for Land-use and Land-cover Change (LULUC).
The categories are “representative” of a huge range, bounded only by the imaginations of those who have contributed something to the literature over the years. The “representatives” have nothing at all to do with real possibilities or statistics or science.
Likelihoods can’t be improved by taking a mean or a median. Each RCP is heterogeneous and was developed by a separate independent consultancy. Each of them already has assumptions about socioeconomic, technology and biophysical futures that differ from the others, and the gap will widen as each team invents and combines different demographic, policy and energy storylines to improve plausibility for its own predetermined outcome.
Any policymaker (or journalist, for that matter) who wishes to rely upon any hypothetical AR5 climate outcome, will first have to choose a RCP.
On perusing the characteristics of the RCPs (see Table 1) one senses that the 4.5RCP comprises the “base case” – which is accompanied by higher (6.0) and lower (2.6) bands, in the usual way.
The inclusion of “surprise” and “disaster” outliers demanded an add-on in the form of the remarkably large 8.5RCP to cover the extremes – those low-probability high-impact events set out in the Table 12.4[5] presented to the Royal Society.
Table 1: Characteristics and Effects of the WG1AR5 RCPs
*Anomalies are calculated with respect to 1986-2005.
**There is no close SRES equivalent to any RCP, but these old narratives provide starting-points for the new evolving storylines.
Naming rights
In the new system the IPCC no longer claims any special insight into the likelihood of high future temperatures. While it opines on the impact of certain cumulative emission levels, those levels are purely hypothetical and unrelated to real world happenings.
This is a step in the right direction. Hyperbolic media articles can no longer claim that doomsday outcomes are ‘projected‘ by the IPCC, even as the extreme end of a range. The 8.5 RCP is unmistakably a “what-if?” or “let’s pretend” speculation.
However, as the narratives are filled out by the IPCC’s joint modeling committee (the JIIC), reverse-engineered pathways will emerge and there will undoubtedly be claims that those pointing to the high-end concentrations are more plausible.
To set up the skewing and spinning process, the IPCC has bestowed a brief description on each RCP:
2.6 sees radiative forcing peak at 3.1W/m2 around 2050 and reduce over the second half of the century. That reduction requires new carbon sinks (either the biosphere or geo-engineering) and therefore new technologies.
4.5 assumes total radiative forcing is stabilized before 2100 by a range of technologies and strategies for reducing greenhouse gas emissions.
6.0 assumes total radiative forcing is stabilized after 2100 without overshoot by a range of technologies and strategies for reducing greenhouse gas emissions.
8.5 is characterized by ever-increasing greenhouse gas emissions and represents those scenarios in the literature leading to high concentration levels (“tipping points”).
IPCC commentators are already referring to 4.5 and 6.0 as “carbon-constrained” and 8.5 as the sole “business as usual” (BAU) case. This unvarnished propaganda is quite likely to appeal to the less discerning members of the alarmist media.
Let us assume our descendants in 2100 find that radiative forcing is at 2.6 or less. What are some of the pathways they might see leading back to 2013?
(i) One or more of the CMIP5 key assumptions were wrong;
(ii) The transient climate response (TCR) was close to 1°C;
(iii) Western fertility rates transferred to Africa and South Asia;
(iv) BRIC economies went into a Japan-type long recession;
(v) Doubling world food supply reduced CO2 concentration rates;
(vi) Energy intensity in the developing world declined in line with income;
(vii) Coal usage ceased as natural gas became ubiquitous and cheap;
(viii) A new energy technology (eg Thorium reactors) became dominant;
(ix) A new CCS or other geo-engineering technology removed CO2 from the atmosphere.
Of this selection, I would have thought the ninth was the least probable. But it suits the IPCC agenda to spin 2.6 as “the geo-engineering case”.
Whatever else the new SPCs may deliver, they have already obscured the reduction in IPCC futures caused by the acceptance of lower climate sensitivity ranges. Not for the first time, the IPCC has found a trick which hides the decline.
The decision to do pure hypothethicals is probably the most defensible approach. In defense planning under reagan for example all of our scenarios were pure hypothethicals. that alllows for building systems that are resilient to various fundamentallly unpredicatable futures. We planned and made decisions under the hypothetical of a two front war. One in the fluda gap and the other on the korean peninsula.
Planning for climate change is not fundamentally different than what we did to defend our country. Of course nobody foresaw the real threat all our scenaros were wrong. Still tge fact that the future was unknowable didn’t freeze us into inaction.
Milodon: “The history of future forecasting is generally pretty funny, but there are occasional flashes of brilliance.”
‘Precognitive Dream’ starting on page 60 of Broca’s Brain by Carl Sagan: (With an absurd ellipsis excision, excerpted from Google Books)
“However, suppose the relative had in fact died that night. You would have had a difficulty time convincing … me that it was merely coincidence. But it is easy to calculate that if each American has such a premonitory experience a few times in his lifetime, the actuarial statistics alone will produce a few *apparent* precognitive events somewhere in America each year. … Such a coincident must happen to *someone* every few months. But those who experience a correct precognition understandably resist its explanation by coincidence. ….
… precognitive dreams — are typical of claims made on the boundary or edge of science. An amazing assertion is made, something out of the ordinary, marvelous or awesome — or at least not tedious. It survives superficial scrutiny by lay people,and, sometimes, more detailed study and more impressive endorsement by celebrities and scientists. … The other explanation often applies when the phenomena are uncommonly subtle and complex, when nature is more intricate than we have guessed, when deeper study is required for understanding; Clever Hans and many precognitive dreams fit this second explanation. Here, very often, we bamboozle ourselves.”
Never forget there’s a glorious difference between a raw number of hits, and the rate between hits and misses. Or even knowing why a hit was a hit. eg. My favorite fortune telling story of all time is the guy that foresaw an airline crash in July. That the plane that crashed had red in its insignia. Came to pass. But then, most airline crashes happen in July, and 70% of the insignias contained red at the time. And the advance knowledge of that was why he made his prediction.
That guy is my minimum bar for what a scientist needs to beat.
Steven Mosher says:
October 20, 2013 at 12:40 pm
Reagan Administration war planning did foresee other scenarios besides Fulda Gap & Korea.
After the 1983 Beirut Marine barracks bombing, the administration used the phrase “war against terrorism” to promote legislation to freeze assets of & otherwise combat terrorist groups.
Jquip says:
October 20, 2013 at 12:47 pm
IPeCaC’s clairvoyants are losing out to precognitive dreamers & odds-counting schemers, failing to clear your minimum bar.
They’re losing more than half the time, so dart-throwing would do better than these violators of the law of averages.
Steven Mosher: “Planning for climate change is not fundamentally different than what we did to defend our country.”
Sure, in defense hypotheticals we ruminated about how we would attack ourselves with gas warfare. In Climate hypotheicals we ruminate about how we would attack ourselves with gas warfare.
Of course, the point in defense planning is to encourage robustness by increasing the number tools we use, being more discerning with their placement, and building infrastructure that would be more resistant to changing warfare conditions.
In Climate change we’re all about increasing fragility, removing redundancy, outlawing the tools we use, and refusing to build infrastructure to assist defense. And discernment of placement, while valid, is vetoed by finding three hairs from a North Cambrian Barking Squirrel.
So sure, it’s all about gas warfare. But all similarities cease there.
Steven Mosher says:
October 20, 2013 at 12:40 pm
There is no scientific justification for “planning for climate change”, & what we’ve done so far has been far worse than doing nothing.
The climate will get warmer over the next 30 to 100 years, get colder or stay about the same. It’s far cheaper to adapt economically to these minor fluctuations than it is to try to control the climate, a system far more complex than simply counting CO2 molecules as they grow from three per 10,000 in dry air to four to possibly five in future & imagining from the increase catastrophic results not only not in evidence, but actually falsified by real observations.
Call me a cynic, denier even, but if the IPCC and its associated scientists can’t or won’t put their names to a mainstream scenario – with limits – and impacts – well what is their purpose? All this scenario building is fine – if one reads the blogs one finds more accurate predictions than the mainstream. So the alarmists won’t “predict” but will “paint alternative possibilities”. Big deal.
In my world they need to say what they think, give a prediction and the key indicators that that prediction is right or wrong, and accept the result. In the real world we have endless obfuscation and the misuse of language. To date the IPCC has broadly been unable to demonstrate a factual and [accurately] measured set of results which support its theories. Its previous predictions have not come to pass.
This is now in the political and even quasi-religious domain now so don’t expect scientific rigour. But demand it all the same.
milodon: If you haven’t heard of the, sadly defunct, monkeydex: http://www.bogleheads.org/forum/viewtopic.php?t=82275
“…Raven, a female chimpanzee who, in 1999, “picked” a portfolio of 10 stocks by throwing darts at a board arrayed with the names of more than 100 Internet companies. MonkeyDex, an indexed fund based on Raven’s picks, wound up ranking among the top Internet funds that year with better than 200% growth. Since then, the phrase “dart-throwing chimp” has stuck in the lexicon of financial analysis as a knock on the “expert” analysts who were outperformed by Raven — and pretty much anyone else who makes a living by prognosticating.
… Had Raven been employed at a Wall Street mutual fund, her performance would rank her as the 22nd best money manager in the country, outperforming more than 6,000 Wall Street pros, according to the Internet Stock Review, creators of the MonkeyDex “
Typo–should be “RPCs.”
Jquip says:
October 20, 2013 at 1:07 pm
Didn’t know about the chimp, but I did follow the stock-picking career of Adam Monk, a capuchin monkey in Chicago.
RCP = Readily Compliant Proletariat
I think that’s the end scenario the UN is looking for.
milodonharlani says:
October 20, 2013 at 1:12 pm
Jquip says:
October 20, 2013 at 1:07 pm
More on random walks down Wall Street:
http://partners4prosperity.com/three-monkeys-and-a-cat-picking-stocks
Adam Monk made news when he beat the legendary Bill Miller.
“The new RCPs are not projections, probabilities, prophecies or pathways – they might possibly be potentialities.”
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If you want to go philosophical at least explain your starting point,
ie: what is a RCP ?
And why would I bother to look up its definition rather than just hit another thread/blog ?
RCP
Yet another acronym for making stuff up?
I have a doom by co2 fantasy for the loons at the IPCC
As atmospheric concentrations of co2 continue to rise, citizen freeze in their homes as poverty prevents them purchasing the needed fuels.Other infrastructure fails due to fantasy planning.
These citizens get very nasty toward unelected parasites operating under the UN banner who feel it is their right to lie to,cheat and steal from, their fellow citizens.
As the “projections”, the RCP’s are revealed as self-serving klepto-speak these same citizens exact their retribution.
Now this is a doom by co2 model, that will most likely happen.
Summary for Policyholders? The IPCC is into insurance now?
Reminds me of this incredibly funny bit of MIT “science:”
http://img.mit.edu/newsoffice/images/article_images/200908311113506360.jpg
[caption: “Okay, everybody look serious for a second. He’s taking our picture.”]
Possible futures. In other words Science Fiction.
Bill Illis: Thanks for the Links
It’s either going to get warmer or it’s going to get colder. Getting significantly colder is a MUCH worse scenario and therefore the one to plan for hoping it doesn’t happen, (too soon…)
Isn’t it about time that the IPCC was moved from the NONFICTION section to the FICTION section?
So, hypothetically, the Representative Concentration Pathways give indications that there are possible potentials that we are, perhaps, and bearing in mind that we are in a coupled non-linear chaotic system which renders all long-term predictions moot, facing, among other alternative futures, doomed?
So, hypothetically, the Representative Concentration Pathways give indications that there are possible potentials that we are, perhaps, and bearing in mind that we are in a coupled non-linear chaotic system which renders all long-term predictions moot, facing, among other alternative futures, one in which we might be doomed?
Thank you for providing a provocative point for discussion, Steve!
In my capacity as a public health scientist, I serve as a subject matter expert on bioterrorism (BT) for the US government. I’ve contributed to the defense of the country since the old Soviet Union “germ warfare” era. In this work, there is a ton of hypothetical “visioning” that we always do, pushing the envelope to the point of extreme science fiction.
We have to balance “assurance” (keeping the public safe, no matter what the cost) and “resilience” (acknowledging that we will take a hit & sustain mortality, but ensuring the survival of society and government systems). The public tends to like assurance, but budgetary restraints always push us towards a more resilient model. Also, in BT, assurance can involve risky vaccination campaigns that carry substantial health hazards. Sometimes it is better to watch, wait and prepare.
Climate change is much like BT. There could be a substantial threat, depending upon circumstances…however, the size & complexity of the problem means that there is only so much we could do to counteract the threat. We could only substantially reduce atmospheric CO2 by drastically reducing all fossil fuel consumption, and that is too high of a price to pay, considering most of the worst damage is likely to be a “real-estate play” (flooding coastal areas etc.).
Sorry if that sounds callous, but I don’t see anything in the data that warrants all-out war to protect ourselves from a raging, rapidly changing climate.
All assume a linear (and potent) connection between CO2 levels and temperature. How about a few hypotheticals that are based on a CS of <1? I think that implodes the whole sham.
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