Guest essay by Marcel Crok, Climate Dialogue
Climate sensitivity is at the heart of the scientific debate on anthropogenic climate change. In the fifth assessment report of the IPCC (AR5) the different lines of evidence were combined to conclude that the Equilibrium Climate Sensitivity (ECS) is likely in the range from 1.5°C to 4.5°C. Unfortunately this range has not narrowed since the first assessment report in 1990.
An important discussion is what the pros and cons are of the various methods and studies and how these should be weighed to arrive at a particular range and a ‘best estimate’. The latter was not given in AR5 because of “a lack of agreement on values across assessed lines of evidence”. Studies based on observations from the instrumental period (1850-2014) generally arrive at moderate values for ECS (and that led to a decrease of the lower bound for the likely range of climate sensitivity from 2°C in AR4 to 1.5°C in AR5). Climate models, climate change in the distant past (palaeo records) and climatological constraints generally result in (much) higher estimates for ECS.
A similar discussion applies to the Transient Climate Response (TCR) which is thought to be more policy relevant than ECS.
We are very pleased that the following three well-known contributors to the general debate on climate sensitivity have agreed to participate in this Climate Dialogue: James Annan, John Fasullo and Nic Lewis.
The introduction and guest posts can be read online below. For convenience we also provide pdf’s:
Introduction climate sensitivity and transient climate response
Climate Dialogue editorial staff
Bart Strengers, PBL
Marcel Crok, science writer
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Seems to me we know pretty well what TCR is by simply correlating
observed temperature trends with estimated GHG forcing.
That excludes flux into the ocean, but the oceans will smooth out that
imbalance for a very long time.
By this measure, TCR is about 1.6K per CO2 doubling equivalent.
If the theory of a nuclear reaction in the Earth’s core is correct (WUWT article) then all these forcing calculations seem to get tossed into a cocked hat.
…(ECS) is likely in the range from 1.5°C to 4.5°C. Unfortunately this range has not narrowed since the first assessment report in 1990.
Global warming will be less than 1.5ºC from current levels. Probably much less. The real threat is global cooling.
The NIPCC also reviewed:
1.1.5 Climate Sensitivity
Climate Change Reconsidered II, Physical Science pp 24-30
WUWT posts on climate sensitivity e.g.
Impact of the Atlantic Multidecadal Oscillation (AMO) on deriving anthropogenic warming rates from the instrumental temperature record, G. R. van der Werf and A. J. Dolman, Earth Syst. Dynam. Discuss., 5, 529-544, 2014 doi:10.5194/esdd-5-529-2014 PDF
Spencer, R.W. and Braswell, W.D. 2011. On the misdiagnosis of surface temperature feedbacks from variations in Earth’s radiant energy balance. Remote Sensing 3: 1603–1613.
How much warming occurs after 15 years of huge increases in man-made CO2?
None.
How much warming occured from 1945 to 1980 agter smaller increases in man-made CO2?
None.
“Climate models, climate change in the distant past (palaeo records) and climatological constraints generally result in (much) higher estimates for ECS.”
What is is about paleo records that leads to high ECS estimates?
As usual, when you ask the wrong question, you get the wrong answer … the right question is, why have billions of dollars spent and hundreds of thousands of man-hours invested in the question NOT been able to narrow the estimates of climate sensitivity at all over the last third of a century? Every other field of scientific endeavor has moved forwards in the last thirty plus years, but climate science has made no progress on this question at all?
Why no progress?
To me, thirty years of no progress means you’ve asked the wrong question. But it’s like the old joke about what’s the difference between a rat running a maze, and a mainstream climate scientist running a maze?
I hold that the reason for no progress is that the concept of climate sensitivity is an outgrowth of an erroneous understanding of how the climate works. The misunderstanding lies in the fundamental claim that the changes in global temperature are a linear function of the changes in forcing. The erroneous equation is
∆T = λ ∆F
where T is temperature, F is forcing, and lambda ( λ ) is climate sensitivity.
Asking the wrong question guarantees nobody will agree on the answer …
w.
PS—Oh, yeah. The difference between a rat running a maze, and a mainstream climate scientist running a maze, is that if you take the cheese out of the maze, the rat stops running …
Marcel, you did not invite a denier expert to write anything; like CS is indistinguishable from zero.
Joe Born says:
May 13, 2014 at 11:02 am
—————————————————
You get a high ECS from the ice-core if you willfully misinterpret the lead-lag relationship between temperature and CO2. What would happen to a pharma company that stated pain causes tumors, and what would happen to a regulator that approved ASA for chemotherapy?
Joe Born
“What is is about paleo records that leads to high ECS estimates?”
Over geologic time frames warming increases the atmospheric CO2 concentration, therefore, it is difficult (especially with low resolution data) to discern whether the CO2 is causing a warming or caused by a warming.
Willis says: ∆T = λ ∆T
where T is temperature, F is forcing, and lambda ( λ ) is climate sensitivity.
================
Where is F?
[Fixed. w.]
Willis : “PS—Oh, yeah. The difference between a rat running a maze, and a mainstream climate scientist running a maze, is that if you take the cheese out of the maze, the rat stops running …”
Well if we removed the cheese (grant money) from the climate maze, there’d be a lot fewer rats running around after it, too.
No difference.
“To me, thirty years of no progress means you’ve asked the wrong question. ”
And the (wrong) question they’ve been asking is “how can we prove that man-made CO2 is the primary driver of climate”.
If they’d been paid to ask “what drives climate” they would surely have got somewhere by now.
The 30 years of failure on the first question means it has been answered, they just don’t want admit it. Sometimes negative results are just a important as positive ones.
Willis said:
∆T = λ ∆T
where T is temperature, F is forcing, and lambda ( λ ) is climate sensitivity.
I have solved the equation. Climate sensitivity = 1.0 .
‘As you can easily see,’ Samuelson said, ‘we’ve been getting better and better. The trend is clear.’ He looked at us expectantly in the dim conference room, his outstretched left hand illuminated by the glare of the projector. Silence, then Irene spoke up: ‘Well, what you’re calling a trend only goes back several weeks. If you went back several quarters the graph would actually show an overall decline with a slight improvement at the end….’
Martin A,
I have just completed an exhaustive peer-review of your answer.
1.0 it is!
Actually, the climate sensitivity is 1.000000000000000000000000000000000000000000
The T measurement error bars cancelled out.
Willis Eschenbach says:
May 13, 2014 at 11:02 am
<<>>
Many other fields of science demonstrate similar stagnation and are taken over by charlatans. In astrophysics mysterious term in Einstein’s equation was “explained” by meaningless dark matter and dark energy, in quantum physics meaningless string theory became combatively dominant (see Lee Smolin’s book “Troubles with physics..”, in nonlinear optics the Maxwell’s equations were solved with gross errors (what?!) leading to wicked theory of optical soliton, the “reputable” (sarc.) journals publish articles that, to any educated physicist, are obvious nonsense (see S.J. Byrnes, R. Blanchard, and F. Capasso, “Harvesting renewable energy from Earth’s mid-infrared emissions” (2014) PNAS vol. 111, no. 11, pp 3927-3932), etc. etc. The scientific progress was always fragile frequently falling victim to incompetence, arrogance and intrigue (see Stephen Brush’s “Should the history of science be rated X?” (1974) Science, New Series, V. 183, No 4130, pp. 1164-1172). However, it seems that, in past 30-50 years the sciences (at least most of the physical sciences) and also the funding of research (i.e. spending taxpayer’s money) became overtaken by fraudsters and incompetents on unprecedented level. Climate “science” is just another victim in the long list.
“Joe Born says:
May 13, 2014 at 11:02 am
“Climate models, climate change in the distant past (palaeo records) and climatological constraints generally result in (much) higher estimates for ECS.”
What is is about paleo records that leads to high ECS estimates?”
In some cases its the error bars. in other cases its the assumptions.
“I have solved the equation. Climate sensitivity = 1.0 .”
Well that would lead to an sensitivity of 3.71 to doubling c02
climate sensitivity is the system response to any increase in forcing.
Say the sun goes up by 1 watt.
The Plank response says temperature will go up by around .4C for a sensitivity of
.4C/wattsm^2
typical figures for lambda run from .4C/wattsm^2 to say 1.5C/watts^2
It seems to me that in the largely inhabited part of the world, when the sun comes up in the morning, on a more or less clear day, everything starts to warm up.
The ground starts to warm up; the ocean surface starts to warm up, the lower atmosphere (troposphere) starts to warm up, and the upper atmosphere starts to warm up.
Where ice and snow exist, their surface layers melt to some extent.
By late afternoon; everything is much warmer than it was at sunrise, in fact it is too warm, so when the sun sets, everything starts to cool down again, and the 24 hour temperature range cycling can easily be 10 to 20 deg. C, or more.
So what this demonstrates is that as thermally massive as the earth is, it can still shift in Temperature in a few hours, much more than all the overall Temperature shift believed to have happened over the last 150 years.
I would say that the earth response to “forcing”, by EM radiation, is darn near instantaneous. There is no 800 year delay between sunrise, and global warming.
What this tells me is that ANY radiative “forcing” due to an increase in atmospheric CO2, such as me running my car engine and putting out H2O and CO2 green house gases, will also cause a virtually instantaneous increase in the Temperature (of something). It may be too small to register on instruments, but it will happen very quickly.
It won’t wait a month or 30 years, or any other extended period; the planet will respond today. before my engine can even cool down after I shut it off.
So the idea of looking over long intervals for something to happen seems pretty silly to me. It has already happened within minutes to hours of the “forcing” being turned on.
So a plot of the daily data from any site, would seem to me to be an accurate account of what really happens at that location.
Plotting trends, or thirteen month running averages, is simply throwing away, weather and climate information, that was obtained at great public expense, and replacing it with false information that was never observed or measured, by anyone at any time in any place.
Now I can’t fault anyone who enjoys doing such machinations and reporting their output; particularly if someone else pays the bill for throwing away all that information.
But the last straw, is when they assert that their faux “information”, will somehow tell them what will happen next.
Jim Cripwell says:
May 13, 2014 at 11:08 am
Marcel, you did not invite a denier expert to write anything; like CS is indistinguishable from zero.
#############
err neither did he invite people who doubt we landed on the moon.
CS = dT/dF
its not indistinguishable from zero.
To make a claim that it is, you have to actually do and show math.
You have to show temperatures, you have to show forcings. you have to show that dT/dF
is statistically indistinguishable from zero.
in short.
A) you can as willis does make a forceful argument that the concept, the CONSTRUCT,
is confused or that the assumptions of construction are not valid.
B) you can claim that we dont know dT, or that we dont know dF.
C) you can claim that dT is uncertain (state your ranges) or dF is uncertain
Yeah, but the units for ∆T are different from ∆T.
It’s really a stupid question to begin with. How long before co2 doubles? And doubles from what base point? and how fast will the doubling take place? The climate scientists have some of you chasing your tails over a question that has no real world value.
“””””…..Greg says:
May 13, 2014 at 11:23 am
Willis : “PS—Oh, yeah. The difference between a rat running a maze, and a mainstream climate scientist running a maze, is that if you take the cheese out of the maze, the rat stops running …”…..”””””
Well the difference between using rats, and using M$ climate $cientists, or even lawyers for that matter, is that there ARE some things, that you just can’t get rats to do !