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.
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Most eloquent and enlightened post – thanks.
Soothsayers or illusionists is the closest fit – it is over, let it be and move on to the next big politically inspired fear all ye morally corrupt politicos and your sycophantic camp followers,
The emissions scenarios are extremely high to begin with. At the current rates of increase of amospheric CO2, its unlikely to even reach 800 ppm by 2100. At current rates of increase, it will take 120 years (2133) to get to 800 ppm. And this is BAU!
Waiting for Oldberg to arrive – with his many elaborate distractions in every other sentences ….
With the 50:1 ratio of CO2 in ocean vs atmosphere it is not possible to get to 1100 ppm. We don’t have that much “fossil fuel”.
“Representative Concentration Pathways” – AGW Newspeak in its very essence and probably as much an exemplar of the genre as anything else I have seen or heard since I first heard the word “denier” used in bilious anger.
For those activists who claim “skepticism” on AGW, but still support the World Empire (“UN”) as a political solution, be honest with yourselves for a change.
The World Empire (UN) stated ability to tax and it’s authority to regulate economic activity will come from greenhouse gas taxation and controls:
UN Decrees “Carbon Budget” for Humanity
The IPCC isn’t just using RCP’s for fanciful future scenarios. They are feeding them into modelled hindcasts and presenting the the 1860-2013 portion of those hindcasts as ‘historical’ which by any intelligent interpretation means the actual instrumental record.
The SPM graph, SPM.10 depicts this so-called historical record as a conveniently precipitous rise with a hike of 0.33 C between 2000 and 2010. At the time it was paraded at the IPCC press conference it had no caption explaining the historical portion was a hindcast leaving all who watched it convinced that global warming hasn’t paused but has gone from 0.2 C/decade to 0.33 C/decade.
More information on this can be found in this article:
http://tallbloke.wordpress.com/2013/10/01/andrew-cooper-ipcc-using-differing-graph-versions/comment-page-1/#comment-60173
Furthermore, crucial details of what might lead to these concentrations were published only recently (population, income), with other crucial details (energy, agriculture, transport) not expected until next year.
Its worse than I thought. I plotted the Mona Loa CO2 since 1958, and extrapolated it out 100 years. By 2100, the CO2 would be at about 600 ppm, at the current rates of increase.
I used an exponential trend line, and the r2 is 0.9854.
A factor in the scenario plausibility that has, in my opinion, been underappreciated is the effect of finite resource constraints on fossil fuel availability: As known reserves are depleted new reserves will, in most cases, be harder and more expensive to find and more expensive to extract, slowly pushing prices higher over time. This will inevitably make fossil fuels progressively less competitive with other energy sources as the future evolves. It is my opinion, based on a review of projected fossil fuel reserves and resources, coupled with energy-demand estimates and likely technology evolution, that something on the order of the rcp 45 scenario is about the greatest fossil fuel use we can ever expect to see. This will cause CO2 concentrations to peak in the latter part of this century or, optimistically, early next century, followed by a slow decline (not by “stabilization”). This process will only be slightly influenced by any governmental efforts at “carbon control”. The rcp 85 scenario is, IMHO, almost physically and economically impossible. Since this conclusion will obviously be controversial I would encourage others to look at the matter more carefully and to help bring it to the attention of the policy-making community.
If they took the current state of the climate as the end of a pathway and tried to work back to the beginning of the twentieth century, I wonder if they would guess that there were a couple of world wars involved? I think it unlikely that the next hundred years wont throw up a couple of suprises as well.
Keith Jackson says:
October 20, 2013 at 10:14 am
Since this conclusion will obviously be controversial I would encourage others to look at the matter more carefully and to help bring it to the attention of the policy-making community.
Most controversial part being that it flies in the face of what we are witnessing.
I propose that the following disclaimer be placed on every page of the next IPCC report-
These potentialities are intended for entertainment value only.*
*ref- Today’s Horoscope, from King Features Syndicate
Really Crap Prognostications came to mind.
Compare modern electrical systems to those in 1900’s. Compare Cars and aircraft.
Undoubtedly technology can and will revolutionise ourr energy use and production in the next 100 years. Inproved nuclear technology, for example thorium reactors. What has been a tragedy is that nuclear research has been throttled over the last 30 years by short sighted government policy and the dreaded greens.
We now live in the most technologically sophisticated and educated era. To try to predict what technology in 100 years will be, and its influence on the world, seems to be rather foolish.
Keith Jackson, I have also wrestled to understand the RCPs in that context. The former ‘BAU’ SRES scenarios like A1B expressly assumed no fossil fuel availability or consumption constraints these land between RCP4.5. and RCP6. For there to be any consistency, the same presumption should apply.
There are any number of serious studies and books on peak fossil fuel production including my own, based on geophysics and past production histories. Lots of hard information. They use three projection methods. Hubbert logistic or gamma functions, Hubbert linearization, or probit transforms. Prof. Deffyes (Princeton geologist) books, or Rutledge Caltech presentations) give details. Even given data uncertainties (e.g. past flared gas, future fracked shale from known deposits with no drilling yet (England gas, China gas and oil), they all conclude that global production peaks will be reached by or before mid century for oil (first), coal ( second) and natural gas (third, with most uncertainty). That says even RCP4.5 may be above business as usual for what can actually be produced ( at sharply increasing cost) when geophysics is necessarily included rather than ignored as it was for the SRES.
Couple that with GCM oversensitivity, and CAGW is not what we should be worried about. Energy yes. climate consequences, no.
Les Johnson says:
October 20, 2013 at 9:06 am
Many assumptions. One being humans are the cause of CO2 rise. If not, no matter whether BAU or not, CO2 levels will be whatever they are for their own reasons. And what will it cost to avoid BAU, even if somehow we did influence CO2 levels, and furthermore those higher levels actually were a bad thing? It seems the cure is far worse than the supposed disease.
Thanks for this excellent deconstruction of IPeCaC-speak.
“(viii) A new energy technology (eg Thorium reactors) became dominant;”
The Max-Planck-Institut für Plasmaphysik made news earlier this year by predicting (projecting?) commercial fusion energy by 2050 & covering about 20 to 30% of Europe’s power needs by 2100 (includes de rigueur genuflection toward the One True Gas):
http://www.ipp.mpg.de/ippcms/eng/pr/publikationen/fusion_e.pdf
Since c. 1955, fusion power has always been about 30 years in the future. Maybe in two more such periods, it will actually arrive, ie c. 2073. The engineering problems do IMO not appear insurmountable.
Excellent article. It is really good to see that even the IPCC has given up any claim to science in these scenarios. But, clearly, the IPCC was unable to take the next step in thought and tell us what these scenarios are. Apparently, they are nothing. They are produced to make good copy for ignorant reporters who will reproduce the chart and then mindlessly explain that it means disaster.
Right, so. Fututology (Gogo Zoidberg) is about possible, probable, and preferable futures; and it’s use was to prophesy doom. The hypotheticals are about possible or probable futures; and it’s use was to prophesy doom. And the projections are about possible or probable futures with the disclaimer: “Runecasting is for entertainment purposes only. But if you don’t do something Right Now, the Runes have prophesied doom.”
Maybe it’s just me, but I’m failing to see a difference here. Hopefully a Futurologist can come by with some Hydromancy and tell me if it’s probable my future self will find it.
Jquip says:
October 20, 2013 at 11:06 am
The history of future forecasting is generally pretty funny, but there are occasional flashes of brilliance. Sci-fi writers have often done better than the pros. Discounting the self-proclaimed clairvoyant C. W. Leadbetter in 1913, the first book featuring atomic power was H. G. Wells’ 1914 novel “The World Set Free”.
Bloke, I have posted elsewhere on how misleading the MSM and ‘offical’ commentary around horizontal fracking of source shale rock is, even though it is making a major transient difference in the US. Thatnwillmformoil last about 10’yeqrs, for natural gas perhapsmbetween 20 and 30. Not longer due to recovery rates and decline curves.
Rather than repeat all the details, one example. The ENTIRE US tight (shale) oil technically recoverable reserve newest upward revised 2013 EIA estimate is 29Bbbl. Half of that is the Monterey shale, where horizontal drilling is not generally possible because of folding and faulting (which fact the EIA buries in an obscure table in a separate footnoted report). By comparison, the remaining TRR of the Ghawar field in Saudi Arabia is 65Bbbl. Ghawar Production started in 1949, and peaked in the 1970’s. Annual production declines as watercut rises with EOR as the Saudis try to prolong field life to squeeze out every last drop. Saudi Aramco now projects exhaustion (not the peak, rather then end) for sometime before 2040. That one field presently supplies 6% of the world’s total oil production. Then entire, forever, total US maybe someday at some price shale oil TRR is half of that one Saudi field.
There is as much bad information out there about the future of oil and gas as there is about CAGW. I am well aware that many here disagree. Unlike climate science where the readers here have dug into the details under Anthony’s able leadership, it would seem that with respect to fossil fuel geophysics many have a lot to learn. Good starting sources include Simmons, Twilight in the Desert, Deffeyes, Hubbert’s Peak and Beyond Oil, or my own books which take on this subject in larger contexts (carrying capacity in the case of Gaia’s Limits, MSM and political spin the the case of The Arts of Truth). Most of the counter arguments are seriously flawed. See, for example my post on Maugeri’s Harvard paper on future oil availability posted at Climate Etc on 2/1/13 titled Another Hockey Stick, http://Www.judithcurry.com/2013/02/01/another-hockey-stick/. Drove Willis nuts, but he never came back with any counterfacts as one would ordinarily expect from someone of his high caliber.
Regards
I think the answers to the purposes of the IPCC report lay with what is going on at the same time with other NGOs like UNEP, UNESCO, and especially the OECD. In my new book I detail the economic, social, and political transformations globally being carried on via education and changing mindsets and the ability to think rationally at all under the banners of Green Growth and Sustainability.
Yesterday I listened to the OECD Secretary-General Angel Gurria at the most recent OECD Forum saying that AGW and the need for a new kind of economy merits a push to take control of institutions directly. Prime among those are of course K-12 schools and higher ed. Institutions that virtually everyone passes through for an extended period of time that are far more subject to the OECD and UNESCO because of the poorly understood nature of accreditation than most people understand.
The most recent IPCC report then may be fictional but it is buying time for the real purpose of the report: the supposed Great Transition. Found the links to the initiative in one of the OECD’s Idea Factory reports.
This IPCC thing has degenerated into a fire and brimstone sermon. An age old pastime, imagining doom for all humankind because you resent the fact that that the world is passing you by.
….am I allowed to say “bullsh*t” on WUWT?