RCP 8.5: The "Mother of all" Junk Climate Science

Guest post by David Middleton

Featured image borrowed from here.

Nearly every catastrophic global warming doomsday scenario, particularity those involving icecap failures and Noah-size sea level rises are based on the “RCP 8.5” scenario.




Representative Concentration (or Carbon)Pathway 8.5 assumes a “rising radiative forcing pathway leading to 8.5 W/m² in 2100.”  It is generally assumed, with little dissent, that each doubling of the atmospheric CO2 concentration will add 3.7 W/m² to the net infrared radiative flux.

A doubling of the supposedly stable pre-industrial CO2 level (280 ppmv to 560 ppmv) should yield 3.7 W/m² of additional forcing to the net infrared radiative flux.  In order to get 8.5 W/m², the atmospheric CO2 concentration would have to rise to 1,370 ppm…



Note: Yes.  The above is from SkepSci.  I checked the math.  It’s close enough.

Does any sane person really believe that the atmospheric CO2 concentration could rise from the current 400 ppm to 1,370 ppm over the next 85 years? (*)

Using BP’s Statistical Review of World Energy 2015, I built a “model.”


Figure 1. Cross-plots of (top) cumulative fossil fuel consumption (MTOE) vs. atmospheric CO2 (ppm) as measured by the Mauna Loa Observatory (MLO) and (bottom) annual fossil fuel consumption (MTOE) vs time.

This “model” derives two equations:

  1. CO2 (ppm) = 0.0002*(MTOE) + 320.87 (R² = 0.9986)
  2. MTOE = 142.16*(Year) – 275,639 (R² = 0.9698)

Note:  MTOE = Millions of Tonnes of Oil Equivalent.

Note to nitpickers:  Yes, I know the top and bottom charts and equations 1 and 2 should have been listed in the opposite order.

These two equations enable me to project fossil fuel use and atmospheric CO2 into the distant future (beyond my retirement date… which with oil at $30/bbl is either very far off in the future or sooner than I would prefer).  Using the assumption that the mix of crude oil, natural gas and coal would remain at a constant ratio (that of the period 2005-2014), I come up with an atmospheric CO2 concentration of 683 ppm in 2100, about half of RCP 8.5 (Venus) and comparable to RCP 4.5 (non-catastrophic).


Figure 2. GIGO is as GIGO does.

The Peak Oilers in the WUWT community will quickly notice that crude oil production in 2100 would have to be about four times that of 2015 for this model to work… In other words, Peak Oil would be delayed again.  My “back of the envelope” calculation says that we would have to find and produce about 4 trillion barrels of crude oil between now and 2100 to comply with this model… Since that is about twice the sum of global proved crude oil reserves and the current estimate of technically recoverable resource potential, I better get back to work finding more oil… 🙂

I didn’t do the calculations for natural gas and coal… because I had to get back to work.  My  best guess is that there is more than enough coal and natural gas in the ground to make it to 2100 without us having to freeze in the dark.

Disclaimer: These models are based on a whole lot of assumptions… But probably not nearly as many assumptions as RCP 8.5.

(*) Addendum

It has been brought to my attention that RCP 8.5 references “CO2-equivalent,” not pure CO2 and that the CO2-only concentration in 2100 is posited to *only* be 930 ppm, not 1130.  930 is still a lot (36%) higher than 683… And 683 was based on the assumption that the ratio of crude oil, natural gas and coal remains constant.  Since natural gas will very likely continue to displace coal and eventually crude oil, 683 is probably unrealistically high as well.

So I will revise and extend my question:

Does any sane person really believe that the atmospheric CO2 concentration could rise from the current 400 ppm to 930 ppm over the next 85 years?  Does any sane person really believe that the atmospheric CO2-equivalent concentration could rise from the current 478 ppm to 1,370 ppm over the next 85 years?  Why would the non-CO2 GHG’s rise at a 25% faster rate than the already improbable RCP 8.5 rate for CO2?



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“It is generally assumed, with little dissent, that each doubling of the atmospheric CO2 concentration will add 3.7 W/m² to the net infrared radiative flux.”
Just curious, should “will” be replaced with “may”?

richard verney

i agree that since it is an assumption, and a general one at that, it would be better to use the expression ‘may’.


I think we should demand “may or may not” in general.

Eugene WR Gallun

Will — May
“It is generally assumed” is a statement. What follows is what the author believes is generally assumed. He believes that it is generally assumed that “CO2 concentration WILL add”. That is what the author is claiming is generally assumed. He is not making the claim that it is generally assumed that “CO2 concentration MAY add”.
WILL and MAY have two different meanings. The author chose to use WILL so it is the meaning assigned to the word WILL that the author intends the reader to find in his statement.
To make this clearer — If the author said “the moon is made of green cheese” he obviously did not say “the moon is made of cottage cheese”. You cannot substitute cottage cheese for green cheese without changing the meaning. So also with WILL and MAY. WILL and MAY have two different meanings and thus they are not interchangeable
We must read what is there. Whether the author is right or wrong about what he is assuming does not change what the thing he is assuming is.
Eugene WR Gallun

Eugene – you may be assuming that the author over thought the distinctions as much as you do.

‘May’ is iffy. ‘Will’ is unambiguous.

John Harmsworth

The grammar is fine. The problem comes from the qualifier or lack thereof. There is no accepted formula that I am aware of for residence time of CO2 in the atmosphere or what happens at the interface of ocean and atmosphere under higher CO2 levels. These factors are likely to have a major impact on where CO2 levels get to.

Eugene WR Gallun

To make my point even clearer — The grammar of either line (using “will” or “may) is perfectly correct — but the meaning of the line is not the same. The author can assume either statement. He chooses to use “will”. The line used cannot be faulted on grammar. Nor could it be faulted on grammar if he had chosen to use “may” instead of “will”.
Eugene WR Gallun

If “It is generally assumed, with little dissent, that each doubling of the atmospheric CO2 concentration will add 3.7 W/m² to the net infrared radiative flux.” then the authors haven’t a clue what they are talking about. The change in radiation absorption with concentration is a logarythmic curve.
The authors of this report do not consider that their conclusions are only supported by models assuming that increasing CO2 causes a temperature increase(despite increased CO2 lagging temperature change) and that the temperature increase caused by CO2 causes increased water vapor in the air- equilibrium climate sensitivity. ECS equation Ts / F = (6.1 IPCC AR3).
Regardless of the ECS value used, the CO2 absorption of energy is well along the logarythmic curve which does not support greatly increasing temperatures in the future. None of the models in use can explain how the earth has gone through dramatic changes in CO2 levels, orbital mechanics, ice ages, and warm periods but the actual climate temperature has stayed within a very narrow range of 278K +/- 3K. The earth obviously has many interacting factors that keep it’s climate in a very stable range that are not considered or calculated in any modeling.


… doubling CO2 adds 3.7W as such, but then there are feedbacks, so the end result we don’t know. I guess the 8.5W is based partly on assumption of large positive H2O feedback.


The problem with climate scientists is that they do not have any quantitative basis for such statements. The value of 3.7W is not based on evidence, nor are the feedbacks built into the climate models. As David Middleton points out, climate scientists wrap these non-evidence based factors into terms they label as ECS (Effective Climate Sensitivity) and TCR (Transient Climate Response). Defining and labelling must therefore make them real.
The physical properties of atmospheric CO2 has been well understood by chemists and engineers since 1954. This paper shows how CO2 in the atmosphere really affects radiation and heat transfer:
The results indicate that doubling of atmospheric CO2 only results in 2.4W/m2 additional absorption of terrestrial radiation, which means that a doubling of atmospheric CO2 will result in an increase of 1.2% of total absorption.

“Will” is correct. Definite assumptions are used for forecasting. Uncertainty is incorporated in the fact that it is an assumption.

Tim Crome

Nice simple engineering approach. When you find more oil and gas I’m keen to help develop it!

There doesn’t seem to be that much conventional light, medium, and heavy oil left to be found. I’m afraid we are also seeing reserves destruction in Venezuela’s Orinoco oil belt (due to poor practices/mismanagement).
There may be additional unconventional oil resources, to be found in very low permeability rocks. But that oil will be very expensive.

Don K

More likely from very heavy oil/tar deposits like the Athabasca Oil sands dontcha think? Looks to me like what’s actually going on in Alberta is a sort of conversion of cheap natural gas — which powers the operation — into expensive, but more convenient, oil. I’m told that there are a LOT of BTUs worth of sludgy hydrocarbons in Alberta and Venezuala (And probably, it’ll turn out, elsewhere).
I’m an optimist who expects hydrocarbon use in developing countries to soar further and faster than most anyone anticipates because they need the power to bring their populations up to a reasonable standard of living. But I agree with David. There will be enough hydrocarbons to get the human race through this century comfortably. The 22nd century? Y’know what? Humanity is eventually going to need those non-carbon technologies to work and work well. Might be as soon as then.

Gloateus Maximus

There is enough coal left for hundreds of years.

And it will be hundreds of years before windmills make sense. Solar might be viable eventually. That means without subsidies. But take away subsidies from windmills and we’ll have thousands of non-working monuments to the gods of misallocation of resources.
Aside from nuclear, there’s no better power source than fossil fuels. They’re the gold standard of inexpensive power production.


Um No, dbstealy Solar is never going to work for this reason.
Lets assume 10 Billion people, Lets assume that the third world bridges the gap to the first world. their domestic arrangements use 30 kWh a day and their work an additional 30kWh a day (per capita), further lets assume they use 63 litres of gasoline a week doing those things they do (Ie one Fill a week) which is 425 MJ x thermal efficiency of 0.35 or around 41 kWh a day, giving a Total per capita energy use of at least 101kWh. Lets further assume that the transport of the products they use consumes another 2 litres each or around 9kWh a day giving a total energy consumption of a rather frugal first world lifestyle of 110kWh a day per capita. The 99.5% reliable energy output (that is the output guaranteed to be available at all times) of solar is around 4W /m2 or around 100 Wh per day per metre squared averaged over the day so you would need 1e10 x 110000/100 or 11,000,000,000,000(11 Quadrillion) square meters or 11 million square km of land for generation. Assuming a packing density of 0.8 gives 14 million square km. Next to account for the efficiency of pumped storage (0.7) and evaporation/cleaning – say 10% and conversion and transmission losses say 5% we get 14/0.55 = 25 Million square km, add to this a quarter of this for the actual storage = 32 Million square km of land required
There is 121 Million Square km of non polar land available 49 Million of which are used to produce food, allowing for the 30% increase in population and 20% to address the poverty gap results in a required cultivation area of around 75 Million square km leaving 55 Million – less 10 Million unsuitable sites, eg himalayas etc or shaded – down to 45 Million square km available. The area requirement for your mega solar farm is therefore 32/45 = 71% of the available earths remaining surface cleared and TILED with 11 Quadrillion 1m squared PV solar panels… How environmentally irresponsible would that be.
Can you see how utterly impractical this is?

Bob Lyman

bobl, I like your illustration of the area requirements associated with all all-solar world, but I think your assumptions lead to too high a level of energy consumption. Some authorities project the world population to peak around 9 billion by 2050 and gradually decline after that. The developing countries may catch up to today’s OECD level of income over the period to 2100, but I doubt that many economists are so optimistic as to believe they will entirely close the gap. In an increasingly urbanized world, transportation systems almost certainly will have to move partially away from individual vehicles for mass transportation to avoid gridlock, so your assumption about gasoline use is therefore probably far too high. Finally, a more realistic (but still extremely “optimistic”) share for solar energy in the global mix by 2100 might be 50%. If you were to develop an alternative scenario using more modest assumptions like these, how much land do you calculate would be required?


Look Bob, if I halved it you would still need 40% of all non agricultural land, tiled with Quadrillions of panels. I still call bunkum on the idea that this is remotely doable, energy density by area is far too low. Solar power is impractical from an engineering point of view, the overbuild required to make it grid reliable makes it totally unwieldy. This is just simple Math.
Neither are countries uniform in size, Just to replace Singapore’s 12.8GW of generation with reliable Solar would take 3000 odd square km of panels. Adding a similar capacity to replace liquid fuels and gas (electric cars and boilers) and you’d need around 6000 square km. Trouble is Singapore is only 719 Square km in size!
How would you anticipate Singapore converts to solar?


A question I ask to get warmists to talk science is “Why doesn’t CO2 fall out of the atmosphere when there is no sunshine?”.

Pamela Gray

Here is another good question to ask warmists: How would the Sun have to do change to add (beyond what it does at peak versus minimum) 8.5 W/m2 to the atmosphere by 2100?

Pamela Gray

added: In general terms, over the course of a single cycle component from high to low activity, TOA change in energy is about 0.2 W/m2, which translates into a buried in the noise change of a fractional hundreths of degrees in temperature. Now ramp that up in a proposed scenario whereby the Sun changes so much that it adds 8.5 W/m2 at its peak. Given the unimaginable solar change necessary for that to occur, it calls into question the ability of something in the atmosphere measured in parts per million to do that.

Eugene WR Gallun

Panela Gray — Very nice. — Eugene WR Gallun

D. J. Hawkins

That 0.2 TOA change is for the imbalance. The actual swing of incoming radiation is about 10 W/m^2. See the graphs in Willis’ article here:
As you can see, it’s already much worse than they thought. 😉

D. J. Hawkins

Correction, the swing is about 20 W/m^2, +10 to -10 around the mean.

See “Atmospheric Moisture Transports from Ocean to Land and Global Energy Flows in Re-analyses” Trenberth et. al. 2011. Figure 10 is most interesting regarding uncertainties.
NASA Grant NNX09AH89G and NOAA under Grant NA07OAR4310051

Very good. Hope your retirement isn’t a lot sooner than you hoped.


“Does any sane person really believe..”
If there’s one thing an alarmist cannot be accused of, it’s being sane.


“we would have to find and produce about 4 trillion barrels of crude oil between now and 2100 to comply with this model”
Well, if we stopped producing oil just to melt glaciers, we might be able to do it…

This entire “guesstimating” of “radiative forcing” shows that this entire GHG paradigm is not physics .
It lacks either fundamental quantitative enabling equations or experimental demonstration of the “trapping” of thermal energy between a surface an a cascade of optical filters to a higher density than the radiant energy impinging on the sequence of filters .
It is nonscience .

Yes, “radiative forcing” is junk science.

Radiative science is junk relative to GHG forcing, but not relative to solar forcing and this is what tends to confuse people who lean left as they tend to like ‘one size fits all’ kinds of solutions.

John Harmsworth

It has actually mutated into anti-science

IPCC AR5 Table AII 4.1 – RCPs
IPCC AR5 Box SPM. 1 – RCPs
IPCC AR5 Table 13.5 – RCP 8.5 has 0.74 (0.52 to 0.98) m sea level rise by 2100.
IPCC AR5 Table 13.8 – RCP 8.5 takes until year 2500 for 1.51 to 6.63 m sea level rise.

The Great Climate Change Bamboozle
“The whole aim of practical politics is to keep the populace alarmed (and hence clamorous to be led to safety) by menacing it with an endless series of hobgoblins, all of them imaginary.”
H. L. Mencken
Earth’s carbon cycle contains 45,000 Gt (E15 gr) +/- 850 GT of stores and reservoirs with a couple hundred Gt/y +/- ?? ebbing and flowing between those reservoirs. (IPCC AR5 Fig 6.1) Mankind’s net contribution (dry labbed by IPCC to make the numbers work) to this bubbling, churning caldron of carbon/carbon dioxide is 4 Gt/y +/- 96%. (IPCC AR5 Table 6.1) Seems relatively trivial to me. IPCC et. al. says natural variations can’t explain the increase in CO2. With those levels of uncertainty how would anybody even know?
Mankind’s alleged atmospheric CO2 power flux (watt is power, energy over time) contribution between 1750 and 2011 was 2 W/m2 of radiative forcing. (IPCC AR5 Fig SPM.5) Incoming solar RF is 340 W/m2, albedo RF reflects 100 W/m2 +/- 30 (can’t be part of the 333), 160 W/m^2 reaches the surface (can’t be part of the 333), latent heat RF from the water cycle’s evaporation is 88 W/m2 +/- 8. Mankind’s 2 W/m2 is obviously trivial.
One popular GHE theory power flux balance (“Atmospheric Moisture…. Trenberth et. al. 2011 Figure 10) has a spontaneous perpetual loop (333 W/m^2) flowing from cold to hot violating three fundamental thermodynamic laws. (1. Energy out of nowhere, 2) perpetual loop, 3) cold to hot w/o work, 4) doesn’t matter because what’s in the system stays in the system) Physics must be optional for “climate” science. What really counts is the net RF balance at ToA which 7 out of 8 re-analyses concluded was cooling, not warming. Of course Trenberth says they are wrong because their results are not confirmed by his model’s warming, which hasn’t happened for twenty years.
Every year the pause/hiatus/lull/stasis continues (IPCC AR5 Box TS.3) IPCC’s atmospheric and ocean general circulation models diverge further from reality.
As Carl Sagan observed, we have been bamboozled, hustled, conned by those wishing to steal our money and rob us of our liberties. Hardly a new agenda.

Anything I have read on climate modeling (Lindzen as an example) has CO2 effects on a curve–the great dispute is whether the curve is logarithmic or exponential. Assuming a constant effect for CO2 doubling would seem to violate the models.


Claiming exponential is simply contrafactual. Willfully ignorant. Any freshman in physics is required to learn that absorption is logarithmic with respect to amount.

Really, according to Beer’s Law it’s linear:
In the case as absorption at the center of the absorption approaches saturation then the dependence approximates logarithmic due to broadening (the situation in the lower atmosphere). More concentrated tends towards a square root dependence.


Phil, absorbance is a logarithmic function of transmission.
A = 2 – log10 %T
The amount of heat absorbed is logarithmic, as you can never get to 100% absorption.
I’m trying to not confuse people by adding unnecessary detail. The final formula is dT = A ln (C1/C0) where A is a constant dependent on the slope of the line you graphed and entire rest of the system.

You said: “Any freshman in physics is required to learn that absorption is logarithmic with respect to amount.”
In optically thin systems where Beer’s Law applies it’s linear as shown above.
Since when is transmission ‘amount’?


%Transmission = 100-%Absorption
Absorbance is a logarithmic function that has no direct physical meaning. It is not a direct measure of the amount of heat that is absorbed. For this reason, it is my opinion that it should NEVER be used for any reason in public discourse to avoid confusion.
If you convert it into units of “Energy absorbed”, you get the
Heat absorbed = A(1-10^(-BC))
This is the situation if there is a finite amount of energy or light that can be absorbed.
A is the energy of the light
B is the slope of that line in your graph
And I confess to hyperbole in my initial post. In summary, there is a rational debate as to the shape of the graph, but that debate is whether it is logarithmic or Arrhenius (it’s generally argued that it is logarithmic for reasons that I can’t remember at this hour, see the “doesn’t hold at high concentrations” quip in the link).
Discussing linear or exponential relationships between temperature and concentrations has as much merit as debating the reality of the moon landing!

Steve Case

On Venus it snows metal and rains sulphuric acid.
Uh huh, all due to an atmosphere that’s 95% CO2 right?
Mars has an atmosphere that’s 95% CO2 and it snows dry ice there.
Tell me again why RCP 8.5 and CO2 is a catastrophic disaster.

Venus is a case of runaway clouds. Without the clouds, the surface would cool owing to the fact that even a 95% CO2 atmosphere at 100 atmospheres is still nearly 50% transparent to LWIR, even more at higher temperatures. Clouds on the other hand are not.

Don K

But the clouds also reflect a lot of incoming solar radiation. Take them away and the planet gets the full pleasure of direct sunlight — which is, my cocktail napkin once told me, about twice as great at 60,000,000 miles as at the Earth’s 90,000,000 miles.


Here’s a laugh, Mercury has ice


Perhaps you need to learn that % by volume isn’t a good measure of concentration when the pressure isn’t specified. 95% of ‘not very much’ is still ‘not very much’!
Mars has a surface pressure of 600Pa compared with Earth at 100kPa and Venus at 9.2 MPa.
So the concentration on Venus is over 10,000X that on Mars regardless of the fact that both are ~95% CO2.
Not to mention the broadening in each case due to pressure and temperature.

Steve Case

So let’s cut to the chase, are you saying that CO2 here on Earth, at 400 ppm and increasing, is a serious problem?

the mother of junk climate science is junk ozone depletion science

“Disclaimer: These models are based on a whole lot of assumptions… But probably not nearly as many assumptions as RCP 8.5.”
Everything about models predicting CAGW is based on numerous bad assumptions that have never been subject to peer review. For example,
* positive feedback increases the sensitivity (owing the T^4, sensitivity decreases as temperature increases)
* the system exhibits massive net positive feedback (data suggests zero or slightly net negative feedback)
* the feedback model assumes an external power supply that is not the Sun (bad mapping to Bode’s analysis)
* power and temperature are linearly related (no it goes as T^4!)
* CO2 drives temperature (data says its the other way around)
* runaway positive GHG feedback is possible (not possible with an atmosphere nearly 50% transparent to LWIR)


The caption on the photo states “On Venus it snows Metal and Rains Sulphuric Acid.” So, my question is, “What is the GHG effect of these vaporized metals on the “global temperature” of Venus? Lead will be a liquid. Mercury and other elements are going to be vaporized and in the atmosphere. How is this accounted. Then, consideration has to be given for the effects of the “Haze.”


We have 0 clues of the geological history of Venus, as a result any guesses are stabs in the dark as a result.

For what it is worth.
Point…..RCP / W/m^2……Change………GtC…..Change
Point vs RCP Excel trendline: y = 1.92x + 0.6, R² = 0.9899
Point vs GtC Excel trendline: y = 452.5x – 182.5, R² = 0.981

This post is complete garbage. Everybdoy should know carbon cioxide is not the only greenhouse gas. That’s why the image from Skeptical Science clearly says “CO2 equiv.” That stands for CO2 equivalent, referring to radiative forcing equivalent to a CO2 level that high. It doesn’t mean anyone actually expects CO2 levels to reach that level.
Given the entire basis of this post is on criticizing the idea CO2 levels will reach a height nobody claims they’ll reach, and that RCP 8.5 doesn’t require CO2 levels reach anywhere near that high, this post has no value. It is not only totally wrong, it is embarrassingly wrong because it shows a complete lack of understanding of even the most basic aspects of the subject being discussed.


It is still nonsense scare mongering by Sks, there is no hope of that scenario, they might as well added the effects of Zombies on total forcing

CO2 “equivalent” contains all of the GHGs, CH4, CO2, etc. and their collective warming relative to CO2.
IPCC AR5 Glossary
Equivalent carbon dioxide (CO2) concentration: The concentration
of carbon dioxide that would cause the same radiative forcing as
a given mixture of carbon dioxide and other forcing components. Those
values may consider only greenhouse gases, or a combination of greenhouse
gases and aerosols. Equivalent carbon dioxide concentration is a
metric for comparing radiative forcing of a mix of different greenhouse
gases at a particular time but does not imply equivalence of the corresponding
climate change responses nor future forcing. There is generally
no connection between equivalent carbon dioxide emissions and resulting
equivalent carbon dioxide concentrations.

Harry Passfield

But our entire life-style is not being changed based on “CO2 equiv” – it’s being changed based on CARBON! WTF is that, Brandon (and SkS)?

See IPCC AR5 Figure 6.1 and Table 6.1.


RCP8.5 is described in Riahi et al “RCP 8.5—A scenario of comparatively high greenhouse gas emissions” Climate Change (2011) [emphasis added] as “the upper bound of the RCPs” and “a relatively conservative business as usual case”. Riahi et al (2011) further states “With few exceptions …. RCP8.5 builds … upon the socio-economic and demographic background, resource assumptions and technological base of the A2r scenario.”
This A2r scenario is described in Riahi et al “Scenarios of long-term socio-economic and environmental development under climate stabilization” (2007) as aiming “to be positioned above .. the 75th … percentile … of the comparable scenario literature, but without all their salient scenario parameters necessarily always falling within this indicative range.”
Basically treat RCP 8.5 as unlikely (in IPCC parlance).


Emphasis didn’t work. I was drawing attention to “comparatively high”.


RCP 8.5 goes well beyond robust. It is as the man says a selection of the 75% extreme elements that will drive GHG emissions. I’d look to RCP 6.0 or 4.5 for robust BAU growth.


I don’t know if the author misread the IPCC data or just repeated an error from Skeptical Science.
But the RCP8.5 level of CO2 in 2100 is about 930 PPM (not 1370)
930 PPM would result in 6.42 W/sq M for the DIRECT effect of CO2. That would lead to an increase of
1.7 C just from the DIRECT effect of CO2. The question then is would be the TOTAL effect after all feedbacks.
Curry’s latest paper posits a factor of 1.7; so a total of 2.94 C.
Most alarmists zero in on the middle of the range from the Charney Report (1.5 t0 4.5); i.e. a factor of 3.0.
This gives you a result of 4.9 C as a result of the 930 PPM.
So, regardless of what CO2 concentration you assume for 2100, the biggest question is that of CO2 sensitivity; probably the most important scientific debate going on today.

Michael Maddocks

This is assuming that Henry’s Law is permanently suspended by whatever thing they invented to replace it.

David L. Hagen

Is Cooling to next Glaciation avoidable?

enough coal and natural gas in the ground to make it to 2100 without us having to freeze in the dark.

Geological evidence shows periodic glaciations with SHORT interglacials. Our climate has been cooling since the Holocene climatic optimum.
The critical question is:
Can we generate enough global warming to avoid descending into another glacial period?


Not a hope, and worse still, such is our understanding (when we cant even say why El Nino’s happen) for example, that our meddling might have an opposite effect.
The arrogance of claiming to understand it all is ludicrous, but then again, the human intellect likes to make up convoluted over complicated constructions to feed said intellect.


Especially in lieu of an elusive truth, bias tends to try frame your research as not a dead end, who likes to admit they wasted years of their life, for example, the BICEP2 gravity wave finders (just because we over interpreted our data doesn’t mean we were wrong) when they were fund to be wrong 😀


Love that clip David 😀
This clip explains perfectly why green activists are experiencing mental problems over climate change 😀


Yeah, it’s even less so, because CO2 in the atmosphere is not dependent primarily on fossil fuel emissions. These are children frightened of monsters under the bed.

The Original Mike M

If CO2 gets that high plants will be working overtime and produce huge amounts of oxygen. When O2 increases high enough we’ll get giant insects, how exciting! http://www.livescience.com/1083-oxygen-giant-bugs.html

The Original Mike M April 5, 2016 at 11:26 am
If CO2 gets that high plants will be working overtime and produce huge amounts of oxygen. When O2 increases high enough we’ll get giant insects, how exciting!

Well they will first have to makeup for the backlog, since over at least the last 20 years O2 has been removed from the atmosphere faster than CO2 has been added.


“Does any sane person really believe that the atmospheric CO2-equivalent concentration could rise from the current 478 ppm to 1,370 ppm over the next 85 years? ”
It appears to me that the AGW science is mostly supported by exaggerations and worst case scenarios that will never come to pass . This appears to be the foundation of their science after all the doom and gloom predictions failed to materialize
Ten years ago, the Pentagon paid for a climate study that put forth many scary scenarios.
Consultants told the military that, by now, California would be flooded by inland seas, The Hague would be unlivable, polar ice would be mostly gone in summer, and global temperatures would rise at an accelerated rate as high as 0.5 degrees a year.
None of that has happened…
The report also became gospel to climate change doomsayers, who predicted pervasive and more intense hurricanes, tornadoes, floods and droughts…Doug Randall, who co-authored the Pentagon report, said, “Even I’m surprised at how often it’s referred to…
Asked about his scenarios for the 2003-2010 period, Mr. Randall said in an interview: “The report was really looking at worst-case. And when you are looking at worst-case 10 years out, you are not trying to predict precisely what’s going to happen but instead trying to get people to understand what could happen to motivate strategic decision-making and wake people up. But whether the actual specifics came true, of course not. That never was the main intent.”…
This Pentagon climate report speaks to the heart of false climate science alarmism that is rampant to day .These alarmist climate science reports are meant to exaggerate and scare people.


I have not checked and read the comments thus far, and I must confess I have not properly gone through the post itself…..so please do forgive me if I am raising a point already just made and dealt with.
But just in case, and in the prospect that I am not arguing at this point in the bases of misinformation, but as this one post deals with climate models and in specific with one of these models, the IPCC RCP.8.5.
So, please,if I have got some thing wrong in principle, or the info is no so correct in regard of the mentioned “climate” model, please do correct me.
So, as far as I know and I can tell, the mentioned model is actually what can be considered as a “hybrid” modeling, where the GCM modeling and its simulation is married to another kind of computer game, an AGW heavy weight “climate” modeling…….where the result of that model are gained out of a computer game AGW heavy model due to an input data to it from a GCM simulation based in a “business as usual” scenario…….
That is what that one in particular stands and is when considered as for a climate model.
Is this true or false, I let it be clarified from others or other sources if some takes it at heart to confirm it or show otherwise…
But as we are at the IPCC and therefor the main official “climate” modeling, there is one more point I would like to make……..when it comes to GCM simulations as per “business as usual scenarios”.
There is this weird thing, never mentioned or highlighted,,,,,,,,, if the “business as usual” GCM simulation depicts so accurately the concentration trend of CO2, the ppm(s) over the duration time as per the length of the simulation in regard to how the data of the reality stands in the consideration of the actual CO2 concentration trend and its expected future evolution, why there is no data given by the authority or the modelers about the relation of the yearly sinks and emissions either in any given time during the simulation or at the end result of the simulation, by showing the actual difference in between (the disbalance) which actually is the main contribution to the actual outcome of the concentration trend itself……
How can the end result, or any other data about the simulation any given time under the consideration regarding the CO2 concentration trend will mean anything at all unless considered in the aspect of its depending in the actual relation of yearly sinks and yearly emissions, and the actual difference in between these two!
If that will show a whole or almost human effect why that info still missing?
*keeps scratching the head*
Why the information that will put every one’s mind at peace about what is the share and the effect of human emissions on the actual concentration trend, as per the GCM simulation, is missing, when in the same time, as far as I know it is claimed that the “business as usual” GCM scenarios have a very good depiction of that trend.
How this could be, why the main piece of the info is missing……and in contrary to it we end up considering silly obfuscated scenarios as due to some weird “hybrid” nonsensical simulations, like the 8.5 one, which in the end actually means nothing more than playing a very heavy AGW computer game…..and considering the result of such a silly computer game as realistic…….
Hope the point is clear enough, and hopefully some one will take it to heart to explain me my wrong in this, if there such as…
thank you….

Johann Wundersamer

Until now no one felt urged to correct you, so
You’r welcome!

Mark - Finland

But energy also leaves the planet at an increasing rate when there is more surface warming,far more than what CO2 is postulated in generating.
John Keher made a simple post about this a couple years ago:
“If the Earth were to warm by 1.1 °C, the amount of energy lost would be almost 4 W/m2 greater than what it lost in 1984. If the Earth were to warm by 3.0 °C which is what is predicted by a doubling of CO2, then the amount of energy lost would be > 10 W/m2 the energy loss that existed in 1984.
The science of this is very clear. The rate at which the Earth loses energy will increase at more than twice the rate that the theoretical CO2 forcing is capable of causing warming to take place. The amount of CO2 in the atmosphere cannot stop the Earth from losing more energy if it warms up. The reasons behind this are the wavelengths of energy that are transmitted by the Earth, but it can simply be shown by looking at the energy loss increase that has taken place over the past 25 years. – See more at: http://theinconvenientskeptic.com/2012/05/the-science-of-why-the-theory-of-global-warming-is-incorrect/#sthash.BXC05EoI.dpuf
The question we should be asking is where is all that additional energy coming from?


It is not and never has been about facts , it is and always has been about politics
with that in mind you can see why wild claims are made .
To be fair , many working in this area have such low scientific ability , along with low levels of personal honour and massive ego’s , that even if they wanted to they could not support their arguments on the basis of facts.

David Middleton, thank you for your short, focused essay.

Berényi Péter

My “back of the envelope” calculation says that we would have to find and produce about 4 trillion barrels of crude oil between now and 2100 to comply with this model… Since that is about twice the sum of global proved crude oil reserves and the current estimate of technically recoverable resource potential, I better get back to work finding more oil… 🙂

You will. In the 34 years between 1980 and 2013 average annual increase of known crude oil reserves was 2.61%, while production only increased by 1.05% per year. The net result is, in 1980 proven reserves were enough for 29 years at constant rate of production, while in 2013 they covered twice that much time, 59 years.
Not the kind of behavior one would expect from a resource on the brink of final depletion.

Johann Wundersamer

This “model” derives two equations:
->This “model” derives of two equations:

Johann Wundersamer

‘Does any sane person really believe that the atmospheric CO2 concentration could rise from the current 400 ppm to 930 ppm over the next 85 years? Does any sane person really believe that the atmospheric CO2-equivalent concentration could rise from the current 478 ppm to 1,370 ppm over the next 85 years? Why would the non-CO2 GHG’s rise at a 25% faster rate than the already improbable RCP 8.5 rate for CO2?’
problem is: such belives are inherent in midst of society.
midst of society tries to stay sane by adhering to such believes.

Dr. S. Jeevananda Reddy

After reversing back the global average temperature curve and from this removing the other components other than anthropogenic greenhouse gases that contributing to global average temperature rise, what will be the real temperature rise at global level — although global average is a misnomer & hypothetical in nature as this factor is not going to affect nature but the localized change only affect it.
CO2 & anthropogenic greenhouse gases — there are several other sources other than fossil fuel use. Prior to 60s we have practically no measurements of greenhouse gases around the world. Yet, with all this the so called global warming is less than 0.15 oC by 2100.
Dr. S. Jeevananda Reddy


Details of the RCP 8.5 scenario can be found at this link. Annual CO2 and CH4 emissions will plateau in 2070 at triple today’s level. Despite burning all that coal, sulfate aerosol emissions will drop by 75%.

I see the CO2-equivalent issue has been addressed. But also consider yourself making this calculation in 1916. You would draw a linear trend line through fossil fuel emissions from 1865-2014 and project that linear growth into the future, finding a year-2015 concentration of about 340ppm. You would conclude with the question: “Does any sane person really believe that CO2 will reach 400ppm by 2015?”. That apparently wouldn’t have been a controversial view at the time. From what I understand Arrhenius initially believed it would take millennia to double atmospheric CO2.
Linear growth calibrated to the period 1965-2014 is a plausible assumption. It’s actually pretty close to what happens in RCP6.0, the low-end “Business-as-usual” scenario, which reaches 670ppm in 2100. But an increasing growth rate is also plausible – it’s been the norm in the historical record to date.
The scenarios are calibrated to a historical emissions inventory and diverge from 2005. Going on from 2005 the same emissions inventory is so far showing growth tracking slightly above RCP8.5, way above RCP6.0. Early days obviously, but no sign that 8.5 is insane from a demand perspective at least.

T Johnson

Can any sane person really believe Armageddon will occur when atmospheric CO2 reaches 900 ppm at some unknown year in the future, when atmospheric CO2 was at least 5,000 ppm in the past (and helped create the oxygen based world we live in). Yes, alarmism sells magazines, papers, votes, funding but c’mon folks, take a deep breath and get back to reality.