Confidence tricks between IPCC AR4 and AR5

Patrick Carlberg writes:

I can’t assess the validity of the values from the climate models presented in AR5 (mostly due to lack of time). But I can tell you there are tricks used in the way they interpret the statistical inference.

One of the key points in the new IPCC report is that the CO2 forcing level of confidence was increased from “High” to ”Very High”. The way this was done was by increasing the uncertainty. The means are about the same in AR4 and AR5 but the uncertainty interval has increased from 0.34 to 0.7.

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In the same graph (In AR5) an estimate of the total anthropogenic radiative forcing is included. Given the uncertainty in the calculations there is no statistical difference between 1980 and 2011.

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My guess is that if the 1950 values were included at the same level of confidence then there wouldn’t be any difference between 1950 and 2011 either.

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Stephen Richards
October 1, 2013 12:14 am

see also SteveMc’s work at climate audit. As described on ‘notrickszone’ this report is an obscenity to science.

Franksw
October 1, 2013 12:16 am

From memory it always used to be 1850 not the interglacial minimum of 1750 that was used as a baseline.

Peter Miller
October 1, 2013 12:17 am

Is this no more than a way for alarmist ‘science’ to deal with the great heresy of natural climate cycles?

Ken Hall
October 1, 2013 12:25 am

From what I have noticed,it seems that when any statistic from AR4 now looks a bit dodgy, they have simply cherry picked a different date range to cover up the uncertainty, then expressed higher confidence in the new date range.

Mike Bromley the Kurd
October 1, 2013 12:26 am

This group of wastrels has taken something they cannot measure and elevated it to the significance of something they can. Uh, how did they manage to do this, and write 5 AR’s to boot?

kadaka (KD Knoebel)
October 1, 2013 12:27 am

IPCC AR5: Now 95% certain this is mostly a Mann-made crisis.

jones
October 1, 2013 12:56 am

Forget all that moddly-woddly stuff.
All the science you ever need is here….
Scared enough yet?
http://www.theguardian.com/environment/interactive/2013/sep/27/climate-change-how-hot-lifetime-interactive
Do I really need to put a “sarc” in here?
Just did….doh!

October 1, 2013 1:07 am

OT
September sunspot number SSN is low ( at its ‘support level’ ) about 40 or even a bit below.
http://www.vukcevic.talktalk.net/SSN.htm
btw. there is a new article about the counting controversy
http://solar-center.stanford.edu/sun-on-earth/NS-Sept-2014-Sunspots.pdf
(they even inflated the year, it is still 2013)

kadaka (KD Knoebel)
October 1, 2013 1:10 am

IPCC AR5: Now 95% certain global warming is mostly anthropomorphic*.
*They saw something natural and non-human and thought it had human attributes, like seeing a smile on a snake, or altruism from politicians and other scavengers and parasites.

Nick Stokes
October 1, 2013 1:19 am

For radiative forcing by CO2, the “Very High” refers to the level of scientific understanding, not the statistic. The reason for the wider CI’s is explained in footnote 14:
“In the traditional RF concept employed in previous IPCC reports all surface and tropospheric conditions are kept fixed. In calculations of RF for well-mixed greenhouse gases and aerosols in this report, physical variables, except for the ocean and sea ice, are allowed to respond to perturbations with rapid adjustments. The resulting forcing is called Effective Radiative Forcing (ERF) in the underlying report. This change reflects the scientific progress from previous assessments and results in a better indication of the eventual temperature response for these drivers.”
IOW, more degrees of freedom are allowed in calculating the response, so necessarily the variability is greater. But it covers more things.

petermue
October 1, 2013 1:21 am

Since release of AR5 SPM, well known German climate alarmist propaganda TV stations (we have a lot!) almost every hour repeat mantra-like
“Global warming has accelerated more than predicted!”
No joke!

George Lawson
October 1, 2013 1:24 am

It is mind boggling to understand why a group of so called scientists want to continue to cheat and lie in everything they do. What is their hidden agenda, and why would professional people want to sully their personal reputations, which they have, in order to promote a cause that cannot be supported with true science? Why do they wish to work together with a collective aim of perpetrating such disgusting behaviour on the worlds population and at such a devastating cost? When the truth is finally accepted, it is to be hoped that the ring leaders of this fraudulent behaviour are brought before their professional bodies to account for why they attempted to bring genuine climate science to such low repute by their totally unfounded assertions.

kadaka (KD Knoebel)
October 1, 2013 1:29 am

vukcevic on October 1, 2013 at 1:07 am:
And as can be clearly seen, a quieting Sun has coincided with a warming Earth.
Perhaps the IPCC should have gathered and considered the peer-reviewed research showing this important relationship.

Jimbo
October 1, 2013 1:45 am
Frank
October 1, 2013 1:52 am

Nick: Radiative forcing was originally defined as the change in flux across the tropopause (after the stratosphere equilibrated). Climate models suggest that every W/m2 of radiative forcing produces different amounts of warming (at equilibrium everywhere). However, the relative radiative forcing for CO2 was chosen as the standard forcing and is defined as unity. So it isn’t at all obvious why its uncertainty should rise.
Patrick: There is no doubt that atmospheric CO2 has risen since 1950 and 1980. The forcing associated with CO2 increases in proportion with the logarithm of the CO2 concentration. There is some uncertainty associated with the proportionality constant, but such constants do not change with time. Therefore there is no doubt that the radiative forcing from CO2 has risen since 1950 and 1980-.

tom0mason
October 1, 2013 2:00 am
Ryan
October 1, 2013 2:07 am

Surely the most obvious confidence trick is the claim that a pause which is now 30% of the overall time-frame of interest is “not statistically significant”?
That’s like saying the first foot of a yardstick should be ignored because it isn’t big enough to be significant.

kadaka (KD Knoebel)
October 1, 2013 2:08 am

From vukcevic on October 1, 2013 at 1:07 am:

btw. there is a new article about the counting controversy
http://solar-center.stanford.edu/sun-on-earth/NS-Sept-2014-Sunspots.pdf
(they even inflated the year, it is still 2013)

And as I expected, Leif Svalgaard has the good stuff:

1800 NS-Sept-2013-Sunspots.pdf (New Scientist, 2013) *new*

Thomas Gough
October 1, 2013 2:16 am

This might be a suitable analogy:- It is found as the result of a survey that 90% of a group of golfers can hit a particular green from 100m. A new survey is made later with the same group of golfers. Now 95% of them hit the green. How is this? Have their skills improved? Investigation reveals the answer. The green has been made bigger.

H.R.
October 1, 2013 2:22 am

I’m 100% certain that the loose change in my pocket is between zero and 1 million dollars. I’m 95% certain that it’s between one and 3 dollars. I’m 90% certain it’s between one and two dollars.
I’m 100% underwhelmed by AR5 with 100% certainty. I’m sure 97% of you agree with me ;o)

Nick Stokes
October 1, 2013 2:43 am

Frank says: October 1, 2013 at 1:52 am
“However, the relative radiative forcing for CO2 was chosen as the standard forcing and is defined as unity. So it isn’t at all obvious why its uncertainty should rise.”

These aren’t relative values. They have a box on the matter in Ch 8 (the first one). Of ERF, which they are using now:
“Land-surface properties (temperature, snow and ice cover and vegetation) are allowed to adjust in this method. Hence ERF includes both the effects of the forcing agent itself and the rapid adjustments to that agent (as does RF, though stratospheric temperature is the only adjustment for the latter). In the case of aerosols, the rapid adjustments of clouds encompass effects that have been referred to as indirect or semidirect forcings (see Chapter 7, Figure 7.3 and Section 7.5), with some of these same cloud responses also taking place for other forcing agents (see Chapter 7, Section 7.2). Calculation of ERF requires longer simulations with more complex models than calculation of RF, but the inclusion of the additional rapid adjustments makes ERF a better indicator of the eventual global mean temperature response, especially for aerosols.”
If they are including things like cloud response, I think the uncertainties just have to be higher.

October 1, 2013 3:25 am

Politicians are easier to fool than intelligent people.

rogerknights
October 1, 2013 3:42 am

George Lawson says:
October 1, 2013 at 1:24 am
It is mind boggling to understand why a group of so called scientists want to continue to cheat and lie in everything they do. What is their hidden agenda, . . . .?

EU bureaucrat Connie Heidegaard let the cat out of the bag on that recently when she said that it would be worth taking mitigation measures even if AGW weren’t real. I’ve suspected this all along. Lots of people get warm fuzzies when they think of “renewable” energy, aid to the 3rd world, less “pollution,” more “environmentalism,” more global cooperation, a bigger role in public affairs for “science” and academia, less of a “consumer culture,” and “sticking it” to big corporations, big oil, and “right-wingers.” What’s not to like? Starting from that POV, the “science” practically writes itself.

October 1, 2013 4:31 am

Stokes – “IOW, more degrees of freedom are allowed in calculating the response, so necessarily the variability is greater. But it covers more things.”
IOW they created the conclusion and then back filled the numbers to fit it.

Jquip
October 1, 2013 5:32 am

Frank — “The forcing associated with CO2 increases in proportion with the logarithm of the CO2 concentration.”
Out of morbid curiosity. Assuming this is true, and that it is included in the models: Then how do the models turn a log curve into an exponential one for temperature prediction?