Denying the Climate Catastrophe: 3. Feedbacks
This is the third chapter of an ongoing series. Other parts of the series are here:
- Introduction
- Greenhouse Gas Theory
- Feedbacks (this article)
- A) Actual Temperature Data; B) Problems with the Surface Temperature Record
- Attribution of Past Warming: A) Arguments for it being Man-Made; B) Natural Attribution
- Climate Models vs. Actual Temperatures
- Are We Already Seeing Climate Change
- The Lukewarmer Middle Ground
- A Low-Cost Insurance Policy
We ended the last chapter on the greenhouse gas theory with this:
So whence comes the catastrophe? As mentioned in the introduction, the catastrophe comes from a second, independent theory that the Earth's climate system is dominated by strong positive feedbacks that multiply greenhouse warming many times into a catastrophe.
In this chapter, we will discuss this second, independent theory: that the Earth's climate system is dominated by positive feedbacks. I suppose the first question is, "What do we mean by feedback?"
In a strict sense, feedback is the connection of the output of a system to its input, creating a process that is circular: A system creates an output based on some initial input, that output changes the system's input, which then changes its output, which then in turn changes its input, etc.
Typically, there are two types of feedback: negative and positive. Negative feedback is a bit like the ball in the trough in the illustration above. If we tap the ball, it moves, but that movement creates new forces (e.g. gravity and the walls of the trough) that tend to send the ball back where it started. Negative feedback tends to attenuate any input to a system -- meaning that for any given push on the system, the output will end up being less than one might have expected from the push.
Positive feedback is more like the ball sitting on top of the hill. Even a small tap will send it rolling very far away, because the shape of the hill and gravity tend to push the ball even further in the direction of the tap. Positive feedback amplifies or multiplies any input to a system, meaning that even small pushes can lead to very large results.
The climate temperature system has a mix of positive and negative feedbacks.
For example, consider cumulus clouds. If the Earth warms, more water tends to evaporate from the oceans, and some of that water will form big fluffy white clouds. These clouds act as an umbrella for the Earth, reflecting heat back into space. So as more clouds form due to warming, there is a net new cooling effect that offsets some of the original warming. The amount of warming we might have expected is smaller due to the negative feedback of cloud formation.
On the other side, consider ice and snow. Ice and snow reflect sunlight back into space and keep the Earth cooler than it would be without the ice and snow cover. As the world warms, ice and snow will melt and thus reflect less sunlight back into space, having the effect of warming the Earth even more. So an initial warming leads to more warming, amplifying the effect of the initial warming.
Since we know both types of feedback exist, what we care about is the net effect -- does negative or positive feedback dominate? In every catastrophic forecast you have seen for global warming, in nearly every climate model the IPCC uses, the authors have assumed that the climate is dominated by strong positive feedbacks that multiply incremental warming from greenhouse gasses many times.
This is the result:
As a reminder, the green line is the warming from increases in atmospheric CO2 concentration solely from the greenhouse gas effect, without any feedbacks taken into account. It is generally agreed to be a warming rate of about 1.2C per doubling of CO2 concentrations, with which I and many (or most) science-based skeptics agree. The other lines, then, are a variety of forecasts for warming after feedbacks are taken into account. You can see that all these forecasts assume positive feedback, as the effect is multiplicative of the initial greenhouse gas warming (the pink, purple, and orange lines are approximately 3x, 5x, and 10x the green line, implying very high levels of positive feedback).
The pink line is the mean forecast from the 4th IPCC, implying a temperature sensitivity to CO2 of about 3C. The purple line is the high end of the IPCC forecast band, implying a temperature sensitivity of 5C. And the highest is not from a mathematical model per se, but from the mouth of Bill McKibben (sorry for the misspelling in the chart) who has on several occasions threatened that we could see as much as 10C of warming from CO2 by the end of the century.
Skeptics have pointed out a myriad of issues with the climate computer models that develop these forecasts, but I will leave those aside for now. Suffice it to say that the models exclude many important aspects of the climate and are subject to hand tuning that allows modellers to produce pretty much any output they like.
But I do want to say a few words about computer models and scientific proof. Despite what you will hear from the media, and even from the mouths of prominent alarmist scientists, computer models do not and cannot constitute "proof" of any sort. Computer models are merely tools we use to derive the predicted values of physical parameters from complex hypotheses. They are no different than the pen and paper computations an 18th century researcher might have made for the position of Saturn from Newton's celestial mechanics equations. The "proof" comes when we take these predicted values and compare them against actual measurements over time and find that they are or are not accurate predictions. Newton's laws were proved as his equations' outputs for Saturn's position were compared to Saturn's actual measured position (and in fact they were disproved, to a small extent, when Mercury's position did not accurately match and Einstein has to fix things a bit). Similarly, hypotheses about global warming will be proved or disproved when the predictions of various models are compared to actual temperatures.
So we can't really get much further until we get to actual observations of the climate, which we will address in the next several chapters. But I want to make sure that the two-part theory that leads to catastrophic global warming is clear.
This is the portion of the warming due to greenhouse gas theory:
As you can see, the portion due to greenhouse gas theory is relatively small and likely not catastrophic. The catastrophe comes from the second independent theory that the Earth's climate system is dominated by strong (very strong!) positive feedbacks.
It is the positive feedback that causes the catastrophe, not greenhouse gas theory. So in debating catastrophic man-made global warming theory, we should be spending most of our time debating the theory that the climate is dominated by strong positive feedbacks, rather than debating the greenhouse gas theory.
But in fact, this does not happen in the mainstream media. If you are an average consumer of climate news, I will be you have never heard a discussion in the media about this second theory.
And this second theory is far from settled. If on the "settled" scale from 1-10, greenhouse gas theory is an 8 or 9, this theory of strong positive feedbacks dominating the climate is about a 2. In fact, there is plenty of evidence that not only are scientists estimating feedbacks incorrectly, but that they don't even have the sign right and that net feedbacks may be negative.
This is a bit hard to communicate to a layman, but the positive feedbacks assumed by the most alarmist and catastrophic climate forecasts are very, very high. Way higher than one might expect in advance upon encountering a new system. This assumption of strong positive feedbacks is one that might even offend the sensibilities of the natural scientist. Natural systems that are long-term stable (and certainly for all its variation the climate system has remained in a pretty narrow range for millions and millions of years) are typically not dominated by positive feedbacks, they are dominated by negative feedbacks.
If in fact our climate temperature system is dominated by negative feedbacks, the future warming forecast would actually be below the green line:
OK, without getting in and criticizing the details of these models (which would by the way be a pointless wack-a-mole game because there are dozens of them) the best way to assess the validity of these various forecasts is to now consult actual observations. Which we will begin to do in our next chapter, part 4a on actual temperature measurements.
"So it's coincidence " There are error bars. Do you have evidence to the contrary? Did they make a mistake or are they lying? How do you know?
It seems that you are claiming that AGW theory is being abused by scientists and economists to benefit crony capitalists, while putting money into their own pockets for research. I guess the small minority of scientists who say the contrary are the great heroes in this story. They can't get government money, so they are funded by public spirited charitable donor money, so they can tell their story. This is very plausible, and the story has been told by Naomi Oreskes, a science historian in her book " The Merchants of Doubt".
It's odd that they don’t even get the irony of quoting oil-funded blogs that called university scientists biased.
The "coincidence" is unbelievably unlikely. It doesn't track at all for 70+ years and then suddenly for another 50, just coincidently the years that their models are designed to curve fit, it tracks exactly to every up and down, and then, just as suddenly, it quits tracking again for another 15.
Yes, I'm not just claiming that AGW theory is being abused by scientists and economists (and politicians and activists) to benefit crony capitalists, while putting money into their own pockets for research, it is. It's the nature of the beast.
Sure there's some who aren't, but there's a lot who are and they're the ones doing the real scare mongering.
Uh huh... and where are you getting your information?
Would you like to take a guess?
...or would you like everyone to simply fill in the blanks?
http://www.ucsusa.org/global-warming/fight-misinformation/climate-deception-dossiers-fossil-fuel-industry-memos
According to whom, Edward?
To you?
What is your word worth?
http://www.nasa.gov/topics/earth/features/vapor_warming.html
"Water Vapor Confirmed as Major Player in Climate Change"
Weather - yes. Global average surface temperature, not so much.
There is the Saturated Greenhouse Effect reasoning.
Infrared optical dept is constrained by clouds.
After clouds form, the increased radiation to space
above the clouds, lowers the clouds. Lower clouds
imply lower surface temperature.
"but I've studied thermodynamics"
Thermodynamics interacts with and dominates radiation to
such an extent, that the lapse (-g/Cp) does not include radiation.
Then, there is Second Law Violation entertainment.
Ok, but on the other hand, do we have precise records of the past? Do we know precisely when CO2 then went above, say, 400 ppmv, or is it uncertain enough that the CO2 level then isn't known to (?) 100 or 200 ppmv (or whatever)?
For example, a recent paper claims 600 ppmv is the point where the Antarctic ice is lost -- though that loss will occur over many millennia.
http://phys.org/news/2016-03-antarctic-ice-sheet-giant.html
Prove your claim, that "the majority of climate models have fun hot...."
"For decades, most scientists who looked at the possible warming effect of increased CO2 believed it would not be significant"
False. As early as 1896, CO2's climate sensitivity was estimated to be 3-4 C.
"On the Influence of Carbonic Acid in the Air Upon the Temperature of the Ground," Svante Arrhenius, Philosophical Magazine 1896(41): 237-76 (1896).
http://www.rsc.org/images/Arrhenius1896_tcm18-173546.pdf
Perhaps someday, lefties will familiarize themselves with the scientific method. But even if they don't, they'll still claim that all those who disagree with them know nothing about science.
Should they bother to look into it, they're going to be slightly confused when they get to step four - testing the data against the hypothesis.
The models created in the 1990s, models which predicted a certain amount of warming, have been laughably wrong. How can anyone take seriously the dire predictions made by scientists whose predictions are at this point a joke? When step four proves your hypothesis wrong, you start over. Unless you're on the far-left, in which case you simply sit back and count on the media to lie about it and frighten the ignorant masses.
When the alarmists can produce the scientists whose models predicted the lack of warming from the start of this century until now, we'll have found someone whose opinion matters. Until then, warmists are basically asking all of us to bet our life savings on the Super Bowl, based on the betting advice of a guy who has yet to predict even one game correctly.
From Chapter 9 of The IPCC Working Group One AR5 report (http://www.climatechange2013.org)
“However, an analysis of the full suite of CMIP5 historical simulations… reveals that 111 out of 114 realizations show a GMST trend over 1998–2012 that is higher than the entire HadCRUT4 trend ensemble… This difference between simulated and observed trends could be caused by some combination of (a) internal climate variability, (b) missing or incorrect radiative forcing and (c) model response error.” – Pg. 769
See also Cowtan, K., et al., 2015, (Robust comparison of climate models with observations using blended land air and ocean sea surface temperatures. Geophysical Research Letters, 42). The authors of the paper adjusted CMIP5 to match the method used to compile observation data. This is a good thing, they were able to account “for 38% of the discrepancy in trend between models and observations over the period 1975-2014.” However, that leaves 62% unaccounted for meaning the models still run hot.
Further analysis of Cowtan et al’s model trends with HadCRUT4 observations, demonstrating the warming bias, is here: http://www.cato.org/publications/working-paper/climate-models-climate-reality-closer-look-lukewarming-world
Is the IPCC now working for the fossil fuel industry? From Chapter 9 of The IPCC Working Group One AR5 report (http://www.climatechange2013.org)
“However, an analysis of the full suite of CMIP5 historical simulations… reveals that 111 out of 114 realizations show a GMST trend over 1998–2012 that is higher than the entire HadCRUT4 trend ensemble… This difference between simulated and observed trends could be caused by some combination of (a) internal climate variability, (b) missing or incorrect radiative forcing and (c) model response error.” – Pg. 769
See also Cowtan, K., et al., 2015, (Robust comparison of climate models with observations using blended land air and ocean sea surface temperatures. Geophysical Research Letters, 42). The authors of the paper adjusted CMIP5 to match the method used to compile observation data. This is a good thing, they were able to account “for 38% of the discrepancy in trend between models and observations over the period 1975-2014.” However, that leaves 62% unaccounted for meaning the models still run hot. Michael Mann is a co-author of that paper as well. I suppose he is also working for the fossile fuel industry too?
Further analysis of Cowtan et al’s model trends with HadCRUT4 observations, demonstrating the warming bias, is at the link below, if you have the fortitude to read a Cato paper: http://www.cato.org/publications/working-paper/climate-models-climate-reality-closer-look-lukewarming-world
In the Cowtan paper, the difference is 0.17C relative to projected warming of 2-4.5C. Not much difference.
I'm at a loss about what the 0.17C is referring to. Would point where you are getting it or explain it a little further? Thanks.
I see you're fine with spelling it out!
Now why are you getting your information from the industry causing the problem if you know your well-being is at stake?
Are you suicidal?
http://www.desmogblog.com/cato-institute
Your NASA link is contradicted by some other sources that say the snowfall amount exceeds the loss due to calving and melting. If future emissions exceed the RCP2.6 pathway the Arctic will start losing ice at an accelerating rate and start adding to sea level rise.
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&uact=8&ved=0ahUKEwiB9Lr765jNAhVJbSYKHaZ3AEEQFggkMAE&url=https%3A%2F%2Fwww.washingtonpost.com%2Fnews%2Fenergy-environment%2Fwp%2F2015%2F11%2F05%2Fa-controversial-nasa-study-says-antarctica-is-gaining-ice-heres-why-you-should-stay-skeptical%2F&usg=AFQjCNHJhS_0GIBkEu1pqYsVUmb0LlqZBg
I answered your question with three references: the IPCC report, the Cowtan paper, and the Cato paper. Each acknowledged the model/observation discrepancies you questioned me about. The IPCC and Cowtan references don't change if Satan himself paid Cato for their study. The fact that they are in agreement (that discrepancies exist) should make you contemplate why.
One other source, also affiliated with NASA, contradicted by the majority of other studies, based on dubious calculations which has also found negative acceleration... It's also an incredibly common Climate Denier quote mine.
uploads.disquscdn.com/images/ebd8ab1ce9ca671a508032f60a30a77c0d3fbd982457a7464618029f6130de1f.png
It's a very good question and it depends very much on the dataset. Trying to apply GEOCARB to the Hirnantian is well-known Climate Denier dishonesty, as you know. When you apply appropriate datasets to the history, a very clear picture emerges. Over long timescales (10my+), the system is binary. It doesn't stay in the middling area where we are now. CO₂ is either above and the Earth is a hothouse, or CO₂ is below and Earth is an icehouse... but there is something else that goes on as well. The icehouses are punctuated by brief, severe deglaciations, and the closer you look, the more clear it becomes that these are due to CO₂ rising above current levels... so even if we haven't triggered a switch to a hothouse Earth planet, we will very likely suffer catastrophic levels of meltdown if we don't remove the carbon we've added to the air.
Thanks for the info. There is a detailed discussion of the shortcomings in the paper I linked to here. Bascially it only consists of altimeter data up to 2008, and conflicts with the gavtitational mass balance method. The use of altimeter data has a flaw, because the density of the snow is needed to convert this into ice mass, and the deposited snow contains air.
http://www.slate.com/blogs/bad_astronomy/2015/11/03/antarctic_ice_still_losing_mass.html
You can guess the deglaciations at 3mya, 15mya, and icehouse onset at 30mya very easily just by looking at the carbon:
http://www.nature.com/ngeo/journal/v4/n7/images/ngeo1186-f1.jpg
There are questions about isostatic rebound as well given the tiny measurements being made...
I have some real problems with the comments Dr. Zwally has made to the media about sea level rise! I think they were far too unequivocal given his team's outlier status. His papers have also been quote-mined by Climate Deniers before and in that instance, he had to go through a process of harmonising his findings with other work and sure enough, they came up with ice loss.
I would stop just short of calling Dr. Z a Climate Denier, though the history really is questionable.
To my knowledge, he's the only person looking at altitude over Antarctica, so I would suggest his work is incredibly important, but I wish he would be more circumspect, at least in his public comments...
CB, good stuff, thanks.
There are about a hundred questions I'd like to ask about this. Can you recommend some reading?
He's something I don't know: why did the Earth entered into its recent (~2-3 M yrs) period of ice age oscillations? In particular, were Milankovitch factors overwhelmed before that by some other forcing?
That report was written before NOAA found errors in the temperature measurements, especially those taken at sea. (See Karl et al in Science magazine, last summer.)
So what you quote is already out-of-date.
Heh heh heh...
I am aware of a number of papers dealing with ice house phases in Earth's history, many of which have been brought to me by Climate Deniers!
Of course, there's the ice core records, CO₂ never surpassing 290PPM for at least 800ky:
ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/epica_domec/edc-co2-2008.txt
I don't know of a version of the Cenozoic paper I just linked to that's not paywalled, but that one's pretty good too for an integration of a number of CO₂ proxies.
These 3 are good discussions of the Eocene-Oligocene transition. The CO₂ threshold is calculated not measured, and the last paper discusses the banded nature of the transition:
geology.geoscienceworld.org/content/38/8/723
http://www.researchgate.net/publication/26807829_Atmospheric_carbon_dioxide_through_the_Eocene-Oligocene_climate_transition
http://www.es.ucsc.edu/~jzachos/pubs/Scher_etal_2011_Geology.pdf
This paper is frequently quote-mined by Climate Deniers because it suggests that CO₂ and temperature are actually decoupled during the Phanerozoic, but the authors readily admit there is no evidence of ice during the Jurassic-Cretaceous cold period (also one with relatively high CO₂):
http://www.researchgate.net/profile/Louis_Francois/publication/12199006_Evidence_for_decoupling_of_atmospheric_CO2_and_global_climate_during_the_Phanerozoic_eon/links/09e4150aa8d25d618f000000
This is a good discussion of the ending of the Karoo ice house, again revealing the banded nature of the glaciations, as well as discussing the evidence for limited polar glaciations in comparison to proper ice sheets as CO₂ rose above 500PPM and it went into the hothouse phase:
digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1103&context=geosciencefacpub
...and finally, the Hirnantian, or end-Ordovician glaciation is examined here by Dr. Seth Young:
http://www.researchgate.net/publication/228371761_Did_changes_in_atmospheric_CO2_coincide_with_latest_Ordovician_glacial-interglacial_cycles
He points to a large, global carbon isotope excursion that coincides with the glaciation that could only have been caused by CO₂ at limiting levels.
That about does it for the Phanerozoic. There were at least 2 more ice house episodes during Earth's history prior to the evolution of complex life known as the "snowball Earth" periods. I haven't read any actual papers on them, but it appears they were caused by low CO₂ and ended by high CO₂ as well. Peter Hadfield discusses them here:
http://www.youtube.com/watch?v=fpF48b6Lsbo
Sorry you asked?
;)
They were overwhelmed by CO₂!
I'm not sure it's appropriate to categorise the Quaternary as a fully separate ice house. From there to the mid-Miocene and from the mid-Miocene to the Oligocene you've got fairly stable CO₂ and most likely reliable 100ky Milankovitch cycles as well.
The forcing that "overwhelmed" this ice house in both boundary instances was CO₂, but apparently not enough to break free and into a full hothouse. It just melted most of the ice on the planet except for very high polar glaciers. Once the ice was gone, the weathering increased, minerals bound with the CO₂, atmospheric CO₂ dropped, yadda yadda yadda and it was back into the icehouse again.
What's likely driving the blips in Earth's history prior to us is movement of fossil carbon deposits in the Earth's crust into seismically active regions. We know this can flip the Earth's climate completely and on 100my time scales because it's happened several times before... and the tiny delta required means it's well within our power to do it again.
Yes! ...and the last one reveals you are someone who is not interested in what's true.
Now why did you bother?
Who's going to take a person like you seriously?
http://www.ucsusa.org/global_warming/solutions/fight-misinformation/exxonmobil-report-smoke.html
Scratch that. I read a paragraph out of context.
Oh, look -- the imbecile troll is polluting this thread, too, with her (poorly) paid propaganda.
Troll: are you ever going to grasp the essential concept of demonstrable causality?
You're asking a SpamTroll for reading material?
Why?
Do you want to become as stupid as she is?
Yes, they have, lying propagandist idiot. Even the warmest years in the last 20 have been BELOW the projections of AR3 climate models.
UCS, troll? How many activist groups, pretending to represent legitimate science, can you dishonestly foist onto threads?
Please learn about baselines.
I fell victim to one of the classic blunders.
“That report was written before NOAA found errors in the
temperature measurements”
The most significant adjustment NOAA made was to reconcile
buoy data with ship measurements. They updated their ERSST data set. On the other hand, HadCRUT4 data, which is the observation set used for comparisons I referenced, uses HADSST3 which already reconciled buoy/ship measurements. What NOAA did not do, however, was to also adjust for a 1945 post war discontinuity that HADSST3 has accounted for. It makes NOAA’s data set run cooler from the Mid-1940’s through the 1970’s, eliminating the cooling period identified by Jim Hanson (as related here: http://earthobservatory.nasa.gov/Features/GISSTemperature/giss_temperature2.php
(You might recognize one of the other charts shown as well)
I've uploaded Bob Tisdale's charts from https://judithcurry.com/2015/12/21/busting-or-not-the-mid-20th-century-global-warming-hiatus/
Tisdale's charts show the ERSST tracks pretty much the HADSST3 data from the 1970s onward, but you can see that without the correction Bob talks about, the mid 20th century cooling effect is eliminated. The overall effect is to give the new ERSST data set a higher warming rate. Is this more accurate or less accurate?
This has been adjusted for baseline changes. (Obviously. Climate scientists learn that in kindergarten.)
One quick glance is all it takes to know that it has not.
How can one (quickly and easily) tell? The starting point for the "paper" (used as a model), and the starting point for the measured data, differ by about 0.3 degrees C.
(Interestingly, that failure to use a proper initialization baseline accounts for the FULL DIFFERENCE between Hansen's "nonfossil fuels" scenario, and present-day global temps.)
CB is one of the most intelligent, knowledgeable and thoughtful people I've ever come across on Disqus.
Calling him/her a "troll" just because you disagree isn't at all convincing.
If you think she's intelligent, then you're probably a ... what's the technical term for it ... a moron.
Unless you can do better than juvenile name calling, we're done here.
Both sets of data start in 1950. (Warming/cooling from 1950-1970 was about zero.)
You're right -- NOAA's adjustments reduce the long-term warming trend.
Bob Tisdale thinks global warming is due to El Ninos. He has no credibility whatsoever and no one who is serious about the subject takes him or his graphs the least bit seriously. He won't even allow debate on his blog.
Moron (which I'll now call you, since you've indicated that CB is "one of the most intelligent"), if you're presenting a model in 1981, and the model doesn't align with data in 1981, then the model is 1) Already a failure, or 2) Dishonestly presented.
Name calling is always a coverup for lack of confidence.
If you want a real discussion, you'll have to discontinue. And apologize.
Except when it's a reminder to all of whom I'm (probably in vain) attempting to educate about the most basic of fundamentals of data presentation.
If you can't discuss and "educate" without name calling, you are a very poor educator.
Goodbye.
Education depends on the student not being willfully ignorant. It also depends on balancing content with the student's capability. Since you're starting from a level of "moron", I offered you some basic basics, which you proceeded to reject, like any other willfully ignorant rube.
What a shame that your genius educational abilities have been ruined by your juvenile personality.