Excerpts from Evidence for Negative Water Feedback
by Clive Best
Abstract: Positive linear climate feedback for combined water effects is shown to be incompatible with the Faint Sun Paradox. In particular, feedback values of ~2.0 W/m2K-1 favored by current GCM models lead to non physical results at solar radiation levels present one billion years ago. A simple model is described whereby Earth like planets with large liquid water surfaces can self-regulate temperature for small changes in incident solar radiation. The model assumes that reflective cloud cover increases while normalized greenhouse effects decrease as the sun brightens. Net water feedback of the model is strongly negative. Direct evidence for negative water feedback is found in CRUTEM4 station data by comparing temperature anomalies for arid regions (deserts and polar regions) with those for humid regions (mainly saturated tropics). All 5600 weather stations were classified according to the Köppen-Geiger climatology [9]. Two separate temperature anomaly series from 1900 to 2011 were calculated for each region. A clear difference in temperature response is observed. Assuming the difference is due to atmospheric water content, a water feedback value of -1.5 +/- 0.8 W/m2K-1 can be derived.
I. INTRODUCTION
The Faint Sun Paradox was first proposed by Carl Sagan [1] who pointed out that the geological evidence that liquid oceans existed on Earth 4 billion years ago appears incompatible with a solar output 30% dimmer than today.
The sun is a main sequence star whose output is known to increase slowly with age. The total change in solar radiation over this long period turns out to be huge ~ 87 W/m2. It has been argued that an enhanced greenhouse effect due to very high CO2 and/or CH4 concentrations could resolve this paradox [2]. However, recent geological evidence does not support CO2 as being responsible but instead the authors propose a greater ocean surface leading lower albedo as a likely solution [3]. Others have suggested that high cirrus clouds effectively warmed the Earth [4]. Although the atmosphere must have been very different before photosynthesis began, the presence of large liquid oceans still implies that clouds and water vapor played a similar role in the Earth’s energy balance then, as they do today.
…
Figure 1: Past temperatures extrapolating backwards from today (T=288ºK) assuming different linear feedback values.
It is apparent that a simple linear positive feedback of +2 leads to unphysical results. The basic problem is that if the temperature falls sufficiently so that 4σT3= F then a singularity occurs ~1.5 billion years ago. Instead a negative feedback value of -2 W/m2K-1 is more compatible both with current temperatures and with the Faint Sun Paradox..
…
IV. CRUTEM4 ANALYSIS
Water vapor feedback in recent climate data have been investigated by studying differences between regions with very low atmospheric water vapor (Deserts and Polar) and those regions with very large water vapor content (Tropical Wet regions). The latest CRUTEM4 data [8] consisting of 5500 individual station data covering global land areas has been studied. Each station was classified by indexing its geographic location against the Köppen-Geiger climate classification [9].
“ARID” stations are defined as those with precipitation values ‘W’ or with climate ‘E’ in [9]. These are situated either in deserts or in polar areas having the lowest atmospheric water column on Earth [10]. “WET” stations are defined as those within fully humid Tropical areas – Climate ‘A’ and precipitation ‘f’ in [9]. These are situated in tropical rain forests or year-round humid climates having the highest atmospheric water column on Earth [10]. Global anomalies have been calculated for both stations ARID and WET stations independently using the same algorithm as used for CRUTEM4. The results are shown in Figure 4.
Figure 4: Temperature anomalies for ARID(DRY) stations in red and WET stations in blue. The smooth curves are FFT smoothed curves. The black dashed curve is an FFT smooth to the full CRUTEM4 global temperature anomalies.
There is a clear trend in the data that ARID stations warm faster and cool faster than WET stations. They respond stronger to changes in external forcing. The WET humid stations respond less than both the ARID stations and the global average.
Climate change is complex and global so it is reasonable to assume that both anthropogenic and natural forcing are reflected in the temperature anomaly data. For a given forcing DS the consequent change in temperature anomaly is gDT where g is a gain factor. The period between 1900 and 2005 is used to measure the temperature rise for each region DT1 and DT2 as given in Table 1. DS is assumed to be global in extent.
Table 1 : Temperature changes for ARID and WET regions and their ratio. Errors on DT are derived from differences between the FFT smooth and a linear fit.
| Period | DT1(DRY) | DT2(WET) | DT1/DT2 |
| 1900-2005 | 1.1 +/-0.1 ºK | 0.8+/- 0.1 ºK | 1.4 +/- 0.2 |
Heat inertia effects due to nearby oceans may cause tropical climates to react slower than desert regions, but not over such long periods. If positive feedbacks from increased water evaporation lead to enhance warming then this should be apparent in the tropics, and this is not observed. In fact the opposite is the case implying a negative feedback. Under the assumption that net water feedback F is present only for the WET stations (taking F=0 for ARID stations) then F can be measured from the data:
DT1/DT2 = 1 – G0F , where DT1 = G0DS and DT2 = G0 (DS+FDT2)
For G0-1 = 3.75W/m2K gives Water Feedback F = – 1.5 +/- 0.8 W/m2K-1
This is compatible with the value needed to resolve the Faint Sun Paradox. As has been pointed out by Lindzen [11] and others, much of the Earth’s heat is transported bodily through evaporation and convection to the upper atmosphere where IR opacity is low and can then escape to space. Therefore water feedback effects depend mostly on the water vapor content of the upper atmosphere. Increased evaporation, convection and consequent rain out could then result in lower humidity in the upper atmosphere. This is a possible mechanism for negative feedbacks in the tropics. Such effects would be largely absent in ARID areas, which have no local sources of evaporation.
Read the entire analysis here, it is well worth your time, well written, and easy to comprehend.
h/t to Scott Gates
I don’t want to be picky, but it would appear that the paper disregards atmospheric enthalpy. There is a considerable difference between the heat required to increase the temperature of a volume of dry (ARID) air and a volume of humid/saturated (WET) air. If this is true this is a major flaw in the paper.
The paper should be assessing the heat content in kilojoules. Temperature alone is meaningless and the incorrect metric for heat content.
(see http://www.engineeringtoolbox.com/enthalpy-moist-air-d_683.html )
The above paper was submitted to Geophysics Research Letters on April 25th. The editor later rejected it on the grounds that “the work appears to represent an incremental advance in our understanding of a problem that has already received attention in the peer-reviewed literature, and extends its conclusions beyond what is supported by the research methods and results“
Phil Clarke says:
May 26, 2012 at 6:45 pm
“,,, a problem that has already received attention in the peer-reviewed literature, and extends its conclusions beyond what is supported by the research methods and results“
Can’t have that, can we?
This is most interesting. I have never fully understood the attractiveness of the the Faint Earth Hypothesis as it is nothing but a model that is based on assumptions, if I remember my Astronomy from all those years ago. This work is filled with assumptions too. That is fine as long as we all remember we are dealing with models based more on assumptions then observations.
“the work appears to represent an incremental advance in our understanding of a problem that has already received attention in the peer-reviewed literature, and extends its conclusions beyond what is supported by the research methods and results“
So the only papers worth publishing are those which support the zeitgeist of the time? And who said science was independant of the social context in which it operates.
Dennis Nikols, P. Geo says:
May 26, 2012 at 7:41 pm
as it is nothing but a model that is based on assumptions
Our understanding of stellar evolution is very good and not just ‘based on assumptions’. We observe stars in all phases of their evolution, so have a direct check on the theory.
The point of the paper is the incompatibility of the Faint Sun and positive water feedback hypotheses. It results in strong paradox.
This is supposed to be news. I do believe I have been saying water feedback is negative (more water vapor, less solar energy absorbed by the earth); almost since we had that faint sun . Heating of the atmosphere is peanuts compared to cooling of the non gaseous part of the earth.
….and along comes Phil Clarke to demonstrate his complete inability to discuss the science in any meaningful manner. Instead he casts aspersions on the paper by noting that it was rejected by some journal. Please Phil, all kinds of good science has been rejected in the past by journals. Turned out that the journals were wrong, and frequently too. But the real problem here is you insisting on cluttering up one thread after another with comments intended to misdirect the reader from the science itself. Being incapable of discussing the science yourself, you have no other tools at your disposal, and so use tactics that are hallmark of trolls.
Phil Clarke says:
May 26, 2012 at 6:45 pm
The above paper was submitted to Geophysics Research Letters on April 25th. The editor later rejected it on the grounds that “the work appears to represent an incremental advance in our understanding of a problem that has already received attention in the peer-reviewed literature, and extends its conclusions beyond what is supported by the research methods and results“
==========================
Thank you for informing us as to the very prompt rejection of this paper. The editor at GRL is really on the ball. Rejection of a submitted paper in less than 30 days. A reference to peer review. By the gang for ‘the cause’? Seems like ‘the peers’ have rubber stamps in hand and reject is the default stamp if it questions previous pal reviews. The approved stamp must be for pal review only.
Thank you again for letting us know pal review still exists. The paper will get a fair vetting here @ WUWT. If not the paper, the concept certainly will.
The oceans feature no diurnal variability, they have enormous heat capacity. This mere fact is ignored even today as the oceans cover 78% of the Earth’s surface hence 78% of the surface does not cool at night..
James Hansen ignored this and claimed that the Earth’s surface temperature should reside at -18C which truly is BS when accounting for the Oceans.
Oceans conduct heat to the atmosphere which for the most part is non-emitting so after a few month lag is accounted for atmospheric temps are driven via SSTs once the heat variations are able to traverse the globe/become mixed.
The faint Sun paradox isn’t really much of a paradox when you account for the Ocean’s heat capacity and reduced evaporation rates with the weaker solar output. The solar winds were also much more vigorous.
Solar irradience varies by over 100W/m^2 between the solstices every year, the effect on cloud cover is one thing but topography is important as the highest Earth surface temperatures by far occur during the minimum insolation (NH Summer).
We weight radiation too high and neglect the thermal inertia present in our climate system.
So…. forget Phil, let’s actually talk some science!
As Ian W points out, it takes a lot more energy to heat humid air than to heat dry air. Agreed. The issue is far more complicated than just measuring temperature. But then dry air also cools a lot faster than does humid air. And, since the theory is that water vapour traps LW emanating from the earth surface, one would expect that if the water vapour feedback were significant, it would show up in the temperature trend regardless. Unless itz effects are so insignificant that they are overwhelmed by enthalpy…. in which case, what the heck are we worried about?
While we’re on the topic, has anyone actually studied the total amount of water vapour in the atmosphere over time? Not certain how one would even measure such a thing, but if there was a way to measure it, my guess is that it hasn’t changed appreciably over time. If there’s no extra water vapour due to the extra 1 degree or so temp rise of the last 100+ years, then… there’s no feedback loop to discuss!
There is a huge amount of scientific disagreement and ambiguity about the nature of CO2’s supposed greenhouse effect. But one thing is for sure, if water vapor is a negative feedback, AGW theory has a major problem.
Yet, regardless of whether water vapor is a negative or positive feedback, CO2 is a trace gas, constituting just a minuscule 1 in 2500 parts of the atmosphere. In previous ages there has been as much 18 times the level of CO2, to 7000 ppm, with no discernible effect on the climate. It’s almost common sense to reason that the ultra-trace gas CO2’s effect doesn’t amount to a hill of beans. As the MIT professor Richard Lindzen puts it: “Claims… that man’s activity have contributed to warming are trivially true but essentially meaningless.” Piers Corbyn, in a comment, takes it further: “Observational evidence gives the possibility that the net effect of CO2 increases on World temperatures may not be ‘only trivial’ but in fact miniscule, zero, or even negative due to errors in some of the science some claim or – I would suggest – hitherto not understood feed-back and competing processes…” There is no empirical evidence that CO2 effects climate scale temperatures: http://www.youtube.com/watch?feature=player_embedded&v=WK_WyvfcJyg
By a strange coincidence, only a few minutes ago I was perusing a paper by Carl Brehmer that I found through Postma’s site, Principia Scientific (by way of James Sexton’s blog), that has marked similarities to this paper in that it looks at latitudinally paired humid and arid locales and compares temperature records looking for feedback signals (also negative, as it turns out):
http://myweb.cableone.net/carlallen/Greenhouse_Effect_Research/Water%20Feedback_files/Is%20Water%20Vapor%20Feedback%20Positive%20or%20Negative.pdf
When I popped over here to see WUWT’s take on Postma, I found this post. Kinda eerie.
REPLY: I ignore anything published by the “slayers” in their fake journal “Principia Scientific”. It isn’t worth anyone’s time – Anthony
The faint young sun paradox is lessened by the theory of high ancient obliquity (viz. G.E. Williams at Google Scholar), which causes hot-water summers at the poles, preventing permanent freezing. Annual high temperatures would be why life seems to have a high-temperature origin. At high obliqities, equatorial continents can become glaciated, misinterpreted as a Snowball Earth.
About a billion years ago, Earth’s obiquity lowered to a critical 54 deg, when the poles are no longer the hottest. Modern obliquites were attained about half a billion years ago, via core-mantle coupling. If Earth’s obliquity had stayed high, it’s hard to imagine life ever flourishing on land.
“”””” davidmhoffer says:
May 26, 2012 at 9:57 pm
So…. forget Phil, let’s actually talk some science! “””””
Best be cautious David; not all Phils are created equal !!
First, has anyone bothered to study the effects of the change in the composition and especially the density of the atmosphere over time? I ask this because today, science has become compartmentalized, no scientist bothers to learn about any branch outside of their own, increasingly narrow specialty. Thus, they don’t seem to know the recently learned fact that the atmosphere is being slowly stripped away by the solar wind (helped by the moons tidal effects) and at a far faster rate than previously believed. This means that as we go back in time, the atmosphere gets progressively thicker. That will effect any greenhouse effect from anything, and will also effect evaporation and how much water vapor the atmosphere can hold and in what form it will take as clouds. So, how would an atmosphere say 5 times thicker than today (and it was probably more dense than that) effect evaporation, the amount of water vapor the atmosphere can hold, clouds, the type and altitude of clouds, the amount of UV radiation at the surface, and many other things? We should not only find out what effect the different composition of the atmosphere back then had (lots of methane etc), but the effect of that at a much higher density.
Second, are we saying that there was a much greater surface area to the ocean back then? We know that when the earth first formed, and was hot, it would be fairly smooth, and after it starts to cool, the crust will start to wrinkle. When it was smooth, the ocean could cover the entire earth, when it wrinkles, dry land will hump up out of it. Are we then to conclude that the crust continued to wrinkle slowly over billions of years, with higher land and deeper and thus smaller in surface area oceans as time went on, and if so, for how long, when did the oceans and land attain the proportions compared to each other that they have today?
Until we know the answers to these questions, how are we to know how much effect water vapor has in an unknown earth with an unknown atmosphere? And why do “scientists” always insist that things were, back then, exactly like they are today? They need to look outside their own little specialty. They need to get out more.
Liquid oceans for 4 billion years despite huge volcanic outbreaks, asteroid strikes, changed atmospheric density and composition and a substantial change in the output of the sun.
The only solution is a strongly negative water cycle response to ANY disruption to the system.
That said, it doesn’t have to be water. Any material capable of a phase change involving latent energy exchanges will do the job such as Methane on some of the outer planetary moons and CO2 itself on Mars where it seasonally gets deposited at the Martian poles as a solid then evaporates in the Martian polar spring.
Interstellar Bill says
“At high obliqities, equatorial continents can become glaciated, misinterpreted as a Snowball Earth.”
“Snowball Earth”/low latitude glaciation only occurred in a brief interval about 700 million years ago. The 3 billion years before that were remarkably free of glaciations at any latitude.
@Ian W Yes you are correct about enthalpy differences. However here we are comparing annual average temperature anomalies for land areas only covering 120 years. Nearly all solar radiation is absorbed by the surface which cools be emitting IR. Greenhouse gasses reduce outgoing IR to space leading to increased surface temperatures to restore overall energy balance. Water is a strong greenhouse gas but has it also has other effects – lapse rate, clouds etc. It is to be determined experimentally if the net feedback is positive or negative.
@Phil Clarke The conclusions of the paper may be correct or they may be false, but a negative feedback is NOT an incremental advance over a positive feedback. I therefore welcome all critical arguments, and stand willing to be corrected if in error.
There is clearly much to discover about the Earth’s early atmosphere, volcanic activity, meteor impacts etc. However, It is remarkable that for over 80% of the Earth’s history geology proves that the surface has been mostly covered in liquid water. That must say something profound.
REVIEWS OF GEOPHYSICS, VOL. 50, RG2006, 29 PP., 2012
doi:10.1029/2011RG000375
The faint young Sun problem
Georg Feulner
Earth System Analysis, Potsdam Institute for Climate Impact Research, Potsdam, Germany
For more than four decades, scientists have been trying to find an answer to one of the most fundamental questions in paleoclimatology, the “faint young Sun problem.” For the early Earth, models of stellar evolution predict a solar energy input to the climate system that is about 25% lower than today. This would result in a completely frozen world over the first 2 billion years in the history of our planet if all other parameters controlling Earth’s climate had been the same. Yet there is ample evidence for the presence of liquid surface water and even life in the Archean (3.8 to 2.5 billion years before present), so some effect (or effects) must have been compensating for the faint young Sun. A wide range of possible solutions have been suggested and explored during the last four decades, with most studies focusing on higher concentrations of atmospheric greenhouse gases like carbon dioxide, methane, or ammonia. All of these solutions present considerable difficulties, however, so the faint young Sun problem cannot be regarded as solved. Here I review research on the subject, including the latest suggestions for solutions of the faint young Sun problem and recent geochemical constraints on the composition of Earth’s early atmosphere. Furthermore, I will outline the most promising directions for future research. In particular I would argue that both improved geochemical constraints on the state of the Archean climate system and numerical experiments with state-of-the-art climate models are required to finally assess what kept the oceans on the Archean Earth from freezing over completely.
The assumptions Dennis is talking about are about the composition of the early Earth atmosphere and about the impact of those components on the themperature of the early Earth. The initial explanation was that the “greenhouse effect” of gases such as CO2, and mainly CH4 and ammonia kept Earth above freezing point. They were assumptions because there was not evidence of big amounts of ammonia in the early Earth atmosphere. Later it was found that ammonia couldn’t be the explanation because is photochemically unstable and renders N2 and H2. .
Other possible explanations are also based on similar assumptions.
Of course.
Let’s not forget that according to this study the earth has had much more water in the early days:
http://sciencenordic.com/earth-has-lost-quarter-its-water
Very interesting! But one thing that immediately struck me, is that the most arid areas of the world are the artic and Antarctic deserts, so I wonder if the crutem4 analysis could simply be explained by cyclical climate in the Arctic. If I were a reviewer, I think I would have asked for a discussion of how the wet/arid difference appears in different latitude bands.
Phil does not think that the ocean surface water cools at night. Yes it does. Having swam in the sea both late afternoon and early morning in the tropics I can assure him that the water is cooler in the morning. Late afternoon the surface gets quite hot in the top meter below that it becomes quite cool.
Everything looses heat if the heat source is removed it is the rate of heat loss that varies between water and earth due to heat capacity and heat conduction through the surface material.
Eric Simpson says:
May 26, 2012 at 10:09 pm
My understanding of the alarmist CAGW ‘argument’ is that the water vapour feedback is positive. Hence, the amplification of the alleged CO2 effect. As you say, a zero effect, or even negative effect of water vapour, completely destroys any CAGW position. It is quite noticeable how this is never really explained by the warmista!
Most of the arguments presented in this paper seems reasonable to me. I would say that pro-CAGW critics could only ignore these results on the basis of the missing greenhouse forcing estimates for the geological past.
http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter2.pdf The IPCC’s best CO2 forcing estimate is 3.6-3.8 Watts per sq. meters per doubling – which includes a net positive feedpack parameter, λ = 0.8 K/(W/m2).
If I try to imagine an absurd world where water vapor acts as an amplifier in case of greenhouse forcing and as a dampener during increases in Total Solar Irradiance (TSI), even the large climate sensitivity estimates presented by the IPCC are not enough to explain away the Faint Sun Paradox. For a period of two billion years, we get a cumulative solar forcing of 40 W/m2. Geological records suggest relatively similar CO2 concentration during the Precambrian, with a best estimate of 6000 ppmv. If we assume a ‘pre-industrial’ level of 280ppmv and accept the IPCC numbers, we get an additional greenhouse forcing of 15.8-16.7 Watts per sq. meters. Large carbon dioxide concentrations can explain only 40-42 percent of the total discrepancy and if we admit that our Earth was (almost) completely unglaciated in 90 percent of her lifetime, the unexplained part becomes larger.
By assuming a zero feedback parameter the total CO2 forcing during a concentration increase of 280 ppmv to 6000 ppmv (which equals 4.4 doublings) is reduced to 4.1-4.5W/m2. It is almost a magnitude smaller than the total change in solar irradiance during the last 2 billion years.
Other naturally occuring greenhouse gases e.g. methane have extremely narrow IR absorbtion bands and we can only measure their atmospheric concetrations in parts per billions of volume: http://noconsensus.files.wordpress.com/2010/04/image71.gif
As far as global temperature records are failing to show steep increases in near surface average temperature, upper-troposphere specific humidity is decreasing according to radiosonde data and explaining the geological past seems impossible with the assumption of a net water vapor feedback I will remain a skeptic of the mainstream/IPCC version of global warming theory.
Could another interpretation be that in the wetter areas certain frequencies are saturated in water vapour so that less increase in feedback is possible, this coupled with more clouds could tip feedback negative? How does cloudiness change in the wet areas correlate with Crutem4?
We wrote this paper in 2002. Excerpt:
Computer models that predict catastrophic human-induced global warming have consistently failed to accurately reproduce past and present climate changes, so their predictions of future climate changes are highly suspect. These models incorrectly assume that increased CO2 concentration is a major driver of atmospheric warming, and also assume large positive feedbacks arising from increased CO2 concentration, for which there is no scientific evidence. Without these speculated positive feedbacks, even a doubling of CO2 concentration would lead to a theoretical warming of only approximately 1º C.
Full paper at http://www.apegga.org/Members/Publications/peggs/WEB11_02/kyoto_pt.htm
Applying Occam’s Razor:
There is a more succinct explanation, as provided by Stephen Wilde, May 26, 2012 at 11:42 pm
“Liquid oceans for 4 billion years despite huge volcanic outbreaks, asteroid strikes, changed atmospheric density and composition and a substantial change in the output of the sun.
The only solution is a strongly negative water cycle response to ANY disruption to the system.”
I might delete the word “strongly” from Stephen’s post, but otherwise agree.
More Occam:
As I have said here before: :there is ample evidence that climate feedbacks are negative – if these feedbacks were strongly positive, life on Earth would be very different, if it existed at all.“
A quote from the postscript on Clive Best’s site: the work appears to represent an incremental advance in our understanding of a problem that has already received attention in the peer-reviewed literature, and extends its conclusions beyond what is supported by the research methods and results
Is this a joke from an editor of a respected peer-reviewed journal? Where are the recommendations on how it would be possible to get this paper accepted? We live in a strange world.
Maybe adding a statement like ‘Our results does not disprove that human activities are causing and will cause catastrophic changes in the global cimate system’ would have been enough to get it through the gatekeepers.
Over the eons the atmosphere very slowly seeps away into space (asteroid impacts may occasionally contribute). It is highly likely that atmospheric pressure was much higher in the past – and the relatively large size of flying dinosaurs and insects of the past would tend to back this up.
Even an increase of just 20% in atmospheric pressure would increase average global temperatures by up to 10 deg C. It is such a large effect that it can easily account for the higher temperatures on earth with the faint early sun. A thicker atmosphere also alters circulation of heat from tropics to pole – reducing the variation in temperature.
It is about time this study was done. I even mentioned it here at WUWT several years ago.That it took so long before being presented is an indication that it was probably thought of and carried out before this and roundly rejected by Pal-review.
I don’t wish to feed the troll, but I looked at the phrase he cut-and-pasted in:
“the work appears to represent an incremental advance in our understanding of a problem that has already received attention in the peer-reviewed literature, and extends its conclusions beyond what is supported by the research methods and results“
And what do I see? That this paper by Clive Best Advances the science Apparently, Dr. Best has provided new information that extends the argument. I guess filthy, errr, phil c, cannot stand that.
Legatus says:
May 26, 2012 at 10:36 pm
First, has anyone bothered to study the effects of the change in the composition and especially the density of the atmosphere over time?
The density may be the key. A thicker atmosphere would be a very different atmosphere all other things being equal. It makes any comparison questionable from the start.
Urederra says:
May 27, 2012 at 2:14 am
The assumptions Dennis is talking about are about the composition of the early Earth atmosphere
He was referring to a model, so one could only assume he meant the solar model, as there are many models for the Earth’s atmosphere. I refer to my other post with a link to the current status of the faint solar paradox. The point is that the paradox is still with us. We cannot make the paradox go away by hand waving about ‘assumptions’.
I’m glad you presented this to a wider audience, Anthony, I personally find it very convincing.
The highest mean annual temperature anywhere on the planet is an equatorial low desert with less than 3 inches of annual rainfall. If water were a positive feedback then the place with the highest mean annual temperature would be a wet equatorial climate not a dry one. Quod erat demonstrandum.
Allan MacRae @ May 27, 2012 at 3:39 am
if these feedbacks were strongly positive, life on Earth would be very different, if it existed at all
This cannot be emphasized enough. With positive feedback, any system will go to the extreme and stay there. Throughout its history, the Earth climate appears to have been remarkably stable, indicating negative feedbacks.
This, for me, is the fundamental lie of the Warmistas.
Interesting paper on feedbacks. I’ve always thought the positive feedback assumptions in GCMs is crazy talk. If in nature, positive feedbacks always more than offset negative feedbacks, the Earth would be similar to Venus, and life would never have evolved.
A few months back, I queried “Real” scientists as to whether they’d ever thought to run their GCMs many times, keeping all data the same, while varying their feedback assumption, from highly negative to highly positve, to see which virtual feedback level best matched the “actual” temperature record, as predicted by each particular model. To me, this seems like a great idea, a slam dunk, given the alleged criticality of anthropogenic CO2 forcings.
You could hear crickets chirping. Although I did get one response. RC regular Hank Roberts flattered me with an answer, informing me that supercomputer time is very expensive (I’ve worked as a software engineer for most of my professional life, so this was not a revelation to me).
Ergo, we can’t spend the relatively little money it would cost to run some computer models now, to see if CAGW is more likely, but we MUST demand the immediate and radical crippling all the western economies by restricting fossil fuel energy. Sometimes these people are just nuts in their imbalance.
John Marshall says:
May 27, 2012 at 2:41 am
“Phil does not think that the ocean surface water cools at night. Yes it does. Having swam in the sea both late afternoon and early morning in the tropics I can assure him that the water is cooler in the morning. Late afternoon the surface gets quite hot in the top meter below that it becomes quite cool.
Everything looses heat if the heat source is removed it is the rate of heat loss that varies between water and earth due to heat capacity and heat conduction through the surface material.”
John, the difference is that the oceans do warm in depths – the sunlight goes up to 200 m, even infrared goes about the first meter deep in the water. (btw, only the DLR from greenhouse goes only 6-8 microns deep – so stops at the surface layer).
When the oceans cool at the surface, it cools only the thin layer of the surface, not in depth. So this colder water will isolate the warmer water from below. It will of course mix, but this takes time. The water from below does not radiate – no IR transmition through water, only at the surface.
This makes oceans behave very differently then rocks which heat a lot at the surface and radiate much fater.
“Increased evaporation, convection and consequent rain out could then result in lower humidity in the upper atmosphere. This is a possible mechanism for negative feedbacks in the tropics.”
This would work by the adiabatic cooling of moist thermals rising to a higher altitude, raising the height of the tropopause and reducing its temperature. The tropopause is highest and coldest over the tropics. The moisture in the stratosphere is controlled by the dew point of the tropopause and that is very low indeed, around -60°C depending on latitude. IR heating of the rising thermals by increased CO2 should cause an increase in altitude of the tropopause by slowing the condensation of water vapor.
Measurable results should be a drop in stratospheric humidity, a rise in the tropopause height (might be difficult to see a trend), a reduction in the tropopause temperature (easier), and an increase in the height of thunderstorms, especially over the tropics as in “The Thermostat Hypothesis.”
Maybe it’s time to add clivebest.com to the sidebar list of blogs?
Best’s analysis is compelling.
Additionally, you don’t even need negative feedback from clouds to limit temp rise from CO2 or any GHG. The weather is a water-vapor driven heat engine.
Consider the weather as a steam-locomotive with the wheel-action the work produced by the heat-engine, and the waste-heat out the stack as the resulting temperature. If you add more heat-input (fuel burned), say from GHGs or increased solar input, some of that added input will result in increased work output, along with some increased heat out the stack. The amounts depend on the efficiency of the engine.
If standard GHG theory says the bare CO2-doubling effect is ~1.2C, the actual rise will be LESS than that, as some of the added fuel input will go into increasing the work output (winds, convection, subsidence, etc). All of the increased fuel burned will NOT just go straight out the stack, as ~1.2C assumes.
IMO, ~1.2C from doubling CO2 is the maximum possible temp increase (w/no heat-engine effects). The actual will be less. If clouds cause negative feedback, the actual temp rise will be even less than that.
“Clive Best gives evidence for negative water feedback in Earth’s climate system using the faint sun paradox and CRUTEM4 data”
I think he made a monumental mistake.
CRUTEM4 data is from 1900 to 2012. Faint Sun is from at least 4 billion years ago (bya).
One cannot compare “current” climatic conditions with paleoclimatic conditions or draw any kind of trend between them as figure 1 tries to do. Certainly not from 4 bya.
Earth was so much more different then than now. We don’t even know how land distribution or ocean currents were in those epochs. How deep the oceans were or how geologically active the planet was. All these and other factors (greenhouse gas concentrations, no oxygen, no plants to name a few) contribute to other climatic conditions with probably other feedback conditions than current climate does with deep cold oceans.
Mickey Reno says:
May 27, 2012 at 6:36 am
RC regular Hank Roberts flattered me with an answer, informing me that supercomputer time is very expensive.
================
There are more than a dozen major climate models that all run with the positive feedback assumption, and not a single model runs with a negative assumption. To have so many models running with the same assumption and not a single model testing the other possibilities is the real waste of money.
When the IPCC says the rise in temperature cannot be explained except as a consequence of CO2, what they are really saying is that it cannot be explained “except under the assumption of positive feedback”.
They haven’t looked at negative feedback and they can’t explain temperatures. From this it is reasonable to conclude that negative feedback may be the overlooked explanation.
Phil says:
May 26, 2012 at 9:50 pm
//////////////////////////////////
It also should not be forgotten that in the early period of Earth’s formation, the earth spun significantly faster such that a day was only about 6.5 hours.
By the time oceans were forming a day may have been about 8 or so hours. Thus the diurnal range in the early period of Earth’s history is likely to be far less than it is seen to be now since the period of cooling was far shorter.
Just a though but it may be that the faster spin rate of the Earth offsets the effects of a faint sun.
This work appears to be a significant finding. One concern I would have is to ensure that the data is not simply modelling differences in latitude between wet and dry regions. Maybe adjust for grid size the way climate data is adjusted as a check.
It is possible the journal is trying to minimize the fallout that such a finding could have on its readership so perhaps the conclusion should be worded in such a way as to minimize the controversy by avoiding reference to GHG, but rather present the paper as “a possible solution” to the faint sun paradox.
The temperature anomaly data for the two samples are correctly weighted for grid sizes. It uses the same algorithm for area weighted averaging as that used by CRU. Also I am not really trying to explain the faint sun paradox as such. Rather I am drawing attention to the contradiction implicit in all models with built in positive feedback from water. The oceans would have long ago boiled away with any positive feedback. It is almost impossible to imagine another scenario where other possible effects (denser atmosphere, methane, geothermal, large tides etc.) conspired so perfectly as to exactly balance the amplifying effect of positive water feedback over the last 4 billion years.
RobL says:
May 27, 2012 at 4:27 am
////////////////////////////////////////////////
Some postulate that atmospjheric pressure was double during the time of the dinosaurs. There are many papers covering the pumping of blood in dinosaurs and flight of pterosaurs which conclude that atmospheric pressure must have been far higher back then.
We also need to remember that earth was so different 4 billion years ago. Good science tells us that land masses were fuzed and ocean currents were much different. The moon was significantly closer with huge tides that rushed into the super continent over long distances. Volcanic activity was most likely greater just to name a few. Does this analysis take any of this into account? My skepticism remains.
At the risk of a sharp rebuke, how do the Faint Sun & a certain, somewhat obsessive scientist’s, Iron Sun theories, fit? If we do have this lump of Iron, as our primary heat source, will its output have varied over the Earth’s history?
SHARP REBUKE: We don’t discuss the “iron sun theory” here, to do so also opens the door to other way out there theory. Go to Tallbloke’s Talkshop for that sort of thing. – Anthony
“”””” Robert of Ottawa says:
May 27, 2012 at 6:07 am
Allan MacRae @ May 27, 2012 at 3:39 am
if these feedbacks were strongly positive, life on Earth would be very different, if it existed at all
This cannot be emphasized enough. With positive feedback, any system will go to the extreme and stay there. Throughout its history, the Earth climate appears to have been remarkably stable, indicating negative feedbacks. “””””
Well the problem is that your assertion Robert, simply is NOT true…”””””With positive feedback, any system will go to the extreme and stay there. “””””
Positive feedback simply means, that a system output generates an additional input signal, that enhances the effect of the original INPUT signal. That additional signal is typically a function of the actual output; not necessarily a linear function.
Say we have a system (reasonably linear), such that an input signal of 1 apple yields an output of 5 oranges. So the gain is 5 oranges per apple. Now we connect up a positive feedback path, with a transfer function of 0.02 apples per orange.
So if my Son applies an input of 1 apple to the system, after some propagation delay time t, the output goes to 5 oranges, and a feedback of 5 x 0.02 (= 0.1) apple is generated and ADDED to the Son’s original apple, raising the system input to 1.1 apples. So at time 2t, the output now goes to
5 x 1.1 = 5.5 oranges, so the feedback amount now changes to 5.5 x 0.02 = 0.11 apples, and the total input now changes to 1.11 apples, yielding an output of 5 x 1.11 = 5.55 oranges at time 3t. well you can see what is happening; the total input will eventually reach 1.111111111111…..apples, and the output will settle down to 5.555555555555…..oranges.
The effect of the POSITIVE feedback of 5 x 0.02 = 0.1 apples per orange, is to change the system gain from 5 oranges per apple to 5.555555555555 oranges per apple, which is what you get from
5 / (1- 5 x 0.02). so the system gain is increased by the positive feedback; but it is not (as described) unstable. But if the positive feedback were increased to 0.2 apples per orange, the the gain would change to 5 / (1 – 5 x 0.2), and the gain would go to infinity.
If we changed the feedback to negative, so we got – 0.02 apples per orange added to the Son’s input of 1 apple, the new gain would be 5 / (1 + 5 x 0.02) = 4.54545454….oranges per apple. The ten times increase in negative feedback, would give 5 / (1 + 5 x 0.2) = 2. oranges per apple, which is quite stable.
The catastrophists are claiming that the feedback is positive, and also equal or greater than 0.2 apples per orange, so we get a runaway deluge of oranges.
I don’t know how many times I have to point out that H2O, O3, and CO2 ALL absorb solar energy from the Son, particularly the first two, and the result is that solar energy never gets to the deep ocean storage; and about half of it is lost to space as LWIR, while the other haf reaces the surface where most of it will prompt more H2O evaporation, thereby increasing the negative feedback. It is the stored ocean and rocks solar energy, that heats the earth; not the puny downdraft of LWIR from the (warm) atmosphere.
Notice I didn’t even have to invoke cloud albedo, to show the H2O negative feedback. A 25% reduction in apples from the sun, would lead to a drier planet, with less clouds, and less water vapor in the atmosphere; a lower albedo and solar energy loss to the atmosphere; but a frozen iceball earth couldn’t happen, because, there would be less clouds, and in the tropics even a 25% reduction in sunlight would be plenty to keep the oceans liquid.
Remember that the polar regions have ice because there is little solar energy there to stop it; that’s why it is cold. The ice is not making the earth cold.
Excellent!
Clive, thank you very much.
I’m linking to this article from my climate and weather pages.
that’s a 2.5 oranges per apple mod, not 2. for the big negative feedback.
Reblogged this on evilincandescentbulb and commented:
The water vapor mops up heat. As the vapor rises it leaves a cooler Earth behind. The water vapor rises and as it does the atmosphere becomes cooler and thinner and the water vapor eventually condenses. As it condenses the water vapor gives up its heat to the cold emptiness of space as the vapor returns to water and forms clouds or freezes and ultimately falls back to earth as rain, sleet, hail and snow.
Global Warming Vaporware and the Perpetual Motion Machine http://wp.me/p27eOk-nL
Really good paper Clive.
It should also be noted that the early Earth was not always warm. It was much colder than today for much of the past 2.4 billion years since the rise of oxygen.
It seems clear that cloudiness is a negative feedback – the climate models and the theory probably have it completely backwards. The water vapour feedback does not appear to be showing up either.
Phil Clarke: “the work appears to represent an incremental advance in our understanding of a problem that has already received attention in the peer-reviewed literature, and extends its conclusions beyond what is supported by the research methods and results“
Didn’t the author of that remark miss the point of the paper? The “standard theory” predicts that the dryer regions should have greater surface temperature increases than the wetter regions; analysis of the wet and dry regions shows that did not happen; ergo, the theory must be modified (at least if the result is replicated by others); the author of the paper presented a conjectured modification. Unless the reviewers are willing to criticize the soundness of the data that were used, the proper course of action would seem to be to publish the paper (perhaps with some changes to improve readability and remove a possible ambiguity, etc., etc., etc.)
richard verney says:
May 27, 2012 at 8:13 am
Some postulate that atmospheric pressure was double during the time of the dinosaurs.
=======
Everyone knows that the atmosphere itself contributes nothing to the warming of the planet. That a planet with an atmosphere would be exactly the same temperature as a planet without an atmosphere, unless the atmosphere has greenhouse gasses.
Ok, I’m just joking. However, I’ve heard this very argument made in lead posts on this site to rebut the notion that pressure as a result of gravity regulates atmospheric temperatures. Folks can’t have it both ways. If only GHG warms the planet, then pressure differences cannot make any difference.
In reality there is nothing unique about GHG in the atmosphere. N2 and O2 reduce outgoing radiation through conduction. Energy that would have escaped as radiation is instead captured as warming of the atmosphere.
N2 and O2 cannot radiate this energy. Instead they return this energy to the surface at night and at the poles through convection. This mimics the mechanism by which CO2 is assumed to warm the surface. Thus, if CO2 warms the planet, so does non GHG. The greater the pressure, the greater the density, the greater the effects of conduction and convection as compared to the effects of radiation.
Ah, nuts. I wrote: predicts that the dryer regions should have greater surface temperature increases than the wetter regions;
It’s the other way around. I wrote what the data showed, not what the “standard theory” predicted.
The water vapor mops up heat. As the vapor rises it leaves a cooler Earth behind. The water vapor rises and as it does the atmosphere becomes cooler and thinner and the water vapor eventually condenses. As it condenses the water vapor gives up its heat to the cold emptiness of space as the vapor returns to water and forms clouds or freezes and ultimately falls back to earth as rain, sleet, hail and snow.
Global Warming Vaporware and the Perpetual Motion Machine http://wp.me/p27eOk-nL
When climatists try to model earth climate as if it was analagous to an electronic feedback amplifier system, they don’t pay a lot of attention to the fit of their analog to reality. In a real electronic amplifier, you have an INPUT SIGNAL and a FORWARD GAIN or TRANSFER FUNCTION, and you get an OUTPUT RESPONSE. You also have another thing present that never shows up in any of the mathematics of the amplifier response including anyFEEDBACK PATHS. That missing element is A POWER SUPPLY OR SOUCE. Every thing an electronic amplifier does, is a consequence of that power supply or source. The rest of the paraphernalia simply controls the power source power, to determine where it goes. If you turn off the power the whole thing quits working; no matter what input signals or feedback loops you hook up.
With the earth system, the power supply is the Son. Well without the Son, we would have a different system, and maybe the heat of the earth core would be the power source for however long that would work.
So it is silly to talk about components of the system affecting each other, and simply ignoring their controlling effect on the power source.
Talking about how green house gases absorb some fraction of waste “heat” trying to escape the earth (it WILL escape), is simply re-rranging the deck chairs on the Titanic. No we all do understand how GHGs work; although some still trot out that silly “trace gas” notion. The trace boron, or phosphorous impurities in the silicon chips in this computer, are orders of magnitude less abundant (relatively), than any of the main GHGs in the atmosphere; and the computer won’t work without those trace impurities.
But meanwhile, there’s a big hole in the ship, and tons of ocean water is pouring in, and it is going to sink, no matter how the deck chairs are arranged. We should be looking to the power source, and how it is modified by controls, and not at the shape of the power or energy leaks in the sytem.
Some GHGs namely H2O, O3, and CO2 affect the power source much more than they affect the leakage.
(1) The climate models have a positive water vapor feedback and yet they don’t predict the climate to warm faster in the tropics than over drier regions. In fact, they predict faster warming in the arctic, as is observed. Hence, Clive’s hypthesis is clearly unwarranted.
(2) Since, over a large range of concentrations, forcing tends to be logarithmic in concentration, there is probably no reason to propose that the regions that are already more saturated would experience a higher enhancement of warming.
(3) The atmosphere is strongly coupled and one is limited in what one can conclude by making these sorts of local arguments.
In other words, Clive’s argument is just another example of why the “AGW skeptics” are not being taken seriously by the scientific community: They are not advancing serious scientific arguments, just floundering in desperation to prove what they want to believe for reasons that have nothing to do with science.
“”””” ferd berple says:
May 27, 2012 at 9:03 am “””
“”” N2 and O2 cannot radiate this energy. “”””
Of course they can; not as molecular resonance specral emissions, but certainly as thermal continuum spectra due to their local gas Temperature (being above zero K). They will stop emitting electro-magnetic radiation, as soon as you stop the N2 and O2 molecules from colliding with each other, or anything else. Under that condition the Temperature of those N2 and O2 molecules becomes zero Kelvins, and they stop radiating, since they do not accelerate, in collisions with other molecules
From Joeldshore.
“”””” (2) Since, over a large range of concentrations, forcing tends to be logarithmic in concentration, there is probably no reason to propose that the regions that are already more saturated would experience a higher enhancement of warming. “””””
You’re a scientist Joel. Please put some numbers to “a large range of concentrations”. Is that a million to one range, or is that a 10% range from 1.0 to 1.1
What does “tends to be” mean in scientific terms. The logarithmic function is a very well defined mathematical function whose properties are well understood. Things are either logarithmic, or they are not logarithmic. Nothing that is not logarithmic, tends to be logarithmic over any range.
So in amospheric CO2 since the Mauna Loa record began to be tabulated, the range of concentration of CO2 has gone from 315 ppm to 393 ppm which is a range of quite close to 1.25 to 1.0 Is that a large range of concentrations ? It’s the only reliably measured range we seem to have. So show us your preferred observed data of “forcing” that either is, or is not logarithmically related to that Mauna Loa data. Would your data (along with ML) be fit better by the functional form y = exp (-1/x^2), rather than y = log(x).
And try to be more scientific with your statements. For example, what means “probably no reason” ? Do you have some statistical analysis on that ?
joeldshore says:
May 27, 2012 at 11:38 am
(1) The climate models have a positive water vapor feedback and yet they don’t predict the climate to warm faster in the tropics than over drier regions. In fact, they predict faster warming in the arctic, as is observed. Hence, Clive’s hypthesis is clearly unwarranted.
>>>>>>>>>>>
Being a physicist, you know full well that SB Law dictates that a given level of forcing must produce a more pronounced temperature increase in the coldest areas of earth and the least in the warmest. BTW, the latitudes just below the arctic circles have actually warmed more than the (colder) arctic regions. The models are once again wrong on that point.
joeldshore;
(2) Since, over a large range of concentrations, forcing tends to be logarithmic in concentration, there is probably no reason to propose that the regions that are already more saturated would experience a higher enhancement of warming.
>>>>>>>>>>>>
Thank you for pointing that out. In other words, the tropics, which for the most part are very high humidity and thus saturated, are, accroding to you, likely to experience very little warming at all. It is good to keep in mind that, as you say, of any warming that does occurr, the least occurrs where it would do the most harm, and the most occurrs where it is most beneficial. Excellent point!
joeldshore;
(3) The atmosphere is strongly coupled and one is limited in what one can conclude by making these sorts of local arguments.
>>>>>>>>>>>>>
Oddly, I was given to understand that LW travels at the speed of light. One would think that areas with the most greenhouse gas presence would be early indicators of warming given that it would still take time for the absorbed LW to be redistributed even in a strongly coupled system.
joeldshore;
In other words, Clive’s argument is just another example of why the “AGW skeptics” are not being taken seriously by the scientific community:
>>>>>>>>>>>>>>>>>>>
That’s getting to be a tired argument Joel. How do you define the “scientific community”? What is “climate science” anyway? Allow me to answer that question as follows.
Climate is a highly complex and chaotic system that cannot be described by a single science. Understanding climate is understanding the intersection of physics, chemistry, biology and statistical analysis. Oddly, when most physicists look at the manner in which climate “scientists” have modeled the physics, they scoff. When chemists look at the manner in which climate “scientists” have modeled the chemistry, they scoff. When biologists look at the tree ring studies done by climate “scientists” they break up laughing. When statisticians look at the way climate “science” has handled statistical analysis of the data, they protest at the incompetance.
Sorry Joel, but the climate “science” community has nothing to do with science. They are a clique unto themselves that ignore the fundamentals of all the disciplines that must be taken into consideration when trying to understand how they interact with one another to result in the big picture we call climate. One might as well define literature as being exclusively comic books and that anything like books, magazines, and so on are all outside the domain of literature.
poppyc*ck!
@Larry Plume P.
Of course.
Let’s not forget that according to this study the earth has had much more water in the early days:
http://sciencenordic.com/earth-has-lost-quarter-its-water
+++++++++++++++++
The Mantle of the Earth is said to contain about twice as much water as the oceans. Could it be that it simply sunk into the mantle over time until it was ‘balanced’? It is very possible that we were ‘Water World’ in the early days.
I accept the thesis that the water feedback is negative. As it is a GHG, the obvious conclusion (more Occam) is that the temperature is controlled almost totally by water vapour as it is the primary GHG and its upper limit switch as well.
I am looking forward to hearing something new from Prof Lu at the Univ of Waterloo on the subject of Ozone, tropospheric and polar. There may be a strong mediating factor there.
Someone mentioned the Solar wind was much higher in the days of the Faint Sun. They there would be less cloudiness, right? It seems to me there is another completely separate argument which is that clouds largely controlled the temperature and compensated for the lower energy input. How does the Faint Sun power multiplied by the inverse of the 10Be record look?
Kev-in-Uk says:
May 27, 2012 at 3:02 am
Eric Simpson says:
May 26, 2012 at 10:09 pm
My understanding of the alarmist CAGW ‘argument’ is that the water vapour feedback is positive. Hence, the amplification of the alleged CO2 effect. As you say, a zero effect, or even negative effect of water vapour, completely destroys any CAGW position. It is quite noticeable how this is never really explained by the warmista!
Smarty Pants says:
May 27, 2012 at 6:00 am
The highest mean annual temperature anywhere on the planet is an equatorial low desert with less than 3 inches of annual rainfall. If water were a positive feedback then the place with the highest mean annual temperature would be a wet equatorial climate not a dry one. Quod erat demonstrandum.
=====================
The basic physics used in these arguements, is junk, manufactured to promote AGW. The KT97 and ilk describes an impossible world – for one, it has completely excised The WATER CYCLE.
In the real world, the Water Cycle cools the Earth by around 52°C from the 67°C it would be without water – think deserts is how I stress this point..
Plus, Carbon Dioxide is fully part of the Water Cycle – all clean, pure rain is Carbonic Acid (as is fog, dew, etc.). In the real world carbon dioxide is not a “ideal gas as AGWScienceFiction teaches”, it is a real gas with volume, weight, subject to gravity, and has attraction.
There is no Greenhouse Effect of a rise from minus 18°C to 15°C by “greenhouse gases warming of 33°C” – it’s a sleight of hand created by distraction, by taking out the Water Cycle.
Think deserts.
If the greenhouse effect was so weak, we would be nearer 255 K than 288 K, so he goes wrong right there when he starts with 288 K for today’s temperature. He probably thought we would not notice this assumption.
Allan MacRae @ May 27, 2012 at 3:39 am
if these feedbacks were strongly positive, life on Earth would be very different, if it existed at all
“”””” Robert of Ottawa says: May 27, 2012 at 6:07 am
This cannot be emphasized enough. With positive feedback, any system will go to the extreme and stay there. Throughout its history, the Earth climate appears to have been remarkably stable, indicating negative feedbacks. “””””
George E. Smith; says: May 27, 2012 at 8:36 am
Well the problem is that your assertion Robert, simply is NOT true…”””””
George – for clarity, can you please be more specific with your concern? For example:
You did not take exception to my statement, but you did to Robert’s – Correct?
So what wording would it take to change Robert’s statement such that you could agree with it?
For example: would adding the word “strong” before “positive” do the job?
Or other?
<i.Bill Illis says:
May 27, 2012 at 8:59 am
Really good paper Clive.
It seems clear that cloudiness is a negative feedback – the climate models and the theory probably have it completely backwards.
We know that anthropogenic aerosols and particulates both increase cloudiness (cloud persistence) and increase the reflectivity of clouds by the same mechanism of reduced droplet size.
It should be obvious what caused climate change over the 20th century.
Sorry to point this out, but the search for truth shouldn’t play favorites.
As to the rejection of Clive Best’s paper, could it be because he used degrees Kelvin? If I was quickly scanning a paper, glancing at the graphs and pics first, and came across that in Figure 1, perhaps I could excuse that as an accidental brain fart. But then it’s repeated in the figure’s description, Table 1, in the text…
If I was an editor, short on time, I’d write this off as amateur grade and reject it out of hand, no reviewers needed.
Well clouds don’t reflect, in the optical sense; well not more than the 2% of Fresnel reflection from water droplets. “aerosols” that reduce droplet size, may result in longer persistence times for clouds, before precipitation occurs. Optically, the water droplets of clouds, scatter rather than reflect. A simple spherical lens illuminated by a collimated beam or a half degree divergence sunbeam, ouputs a highly divergent beam (after first going through focus less than a droplet diameter away from the droplet). That output beam covers almost a full hemisphere, and multiply Fresnel reflected beams send some energy over the full 4 pi steradians. It only takes a few (3-5) sequential scatterings to completely homogenize the light so the cloud looks isotropic; but it is NOT reflecting (much). Those optical scattering properties are largely unaffected by droplet size, unless it gets down to where diffraction effects dominate, and all that does is scatter the light even more. But bigger droplets will rain out sooner.
“””””
Allan MacRae says:
May 27, 2012 at 4:05 pm “””””
Alan, you are correct my statement did NOT refer to you post; and I did specifically state that it was Robert’s assertion that was false (that all positive feedback systems will go to a limit and stay there)
As to your assertion Allan, “”””” Allan MacRae @ May 27, 2012 at 3:39 am
if these feedbacks were strongly positive, life on Earth would be very different, if it existed at all “””””
Pretty inoccuous I would say; how could anyone disagree with that; I mean there could be unstable positive feedbacks that could blow the planet to smithereens. Can’t name any off hand; but as you say “if”.
I sometimes have difficulty in determining who said what, as some peole cite other without delimiters. That’s why I always use my patented delimiter; “”””” Balderdash @#!$% “””””
I don’t think I have seen it in the OED yet; or even Websters for us ‘Mercans ! Maybe before I die, I will get recognition.
George
On the base question, I demonstrated how positive feedback can increase “gain” , and negative feedback decrease it.
Two leading shoe drum brakes, have positive feedback; but that doesn’t mean that you tap on the brakes, and your car comes to a complete and sudden stop, with the brakes locked up. Regenerative radio receivers have positie feedback and have had for centuries; well one anyway.
Oh I didn’t address your question Allan; what would fix Robert’s statement. Yes large positive feedbacks would drive things towards a limit. You can’t say for sure that the system would stay there. Depends for example on whether the system is “DC coupled” or “AC coupled”. A DC coupled system does not indefinitely propagate the result of some “steady state”. An AC coupled system only propagates signals that are changing above some minimum rate; so a steady state; such as up against a brick wall, will stop generating a feedback signal if nothing is changing, so the output would eventually collapse, which likely would set off a mad dash for the brick wall on the other side of the road.
So Robert’s statement that the system would stay at the limit condition is only true, if that limit state is a stable state, that can persist indefinitely.
Feedback systems, have a “loop gain” which is the “forward gain”, say 5 oranges per apple, and a “feedback function” say 0.02 apples per orange. The loop gain is the product of those two; in this case 0.1 (no units) If this were a positive feedback the overall gain is 5 / (1 – 5 x 0.02), which is 5.5555555……. so it is stable. If the feedback were negative, the gain would be 5 / (1 + 5 x 0.02) = 4.54545454……..
If the feedback function increased to 0.2 apples per orange, then the positive feedback gain would go to infinity, and the negative feedback gain would drop to 2.5 which is stable.
If the system is AC coupled and excessive positive feedback ( loop gain >=1.0), then it will oscillate; but if DC coupled, it will jam up as Robert asserted.
There are more elaborate conditions for stability, specially ones that involve the time response of the system. Large propagation delays tend to result in oscillation, because an intended large negative feedback , in an AC or DC coupled system, is delayed so much, that by the time it gets to the input again, it is out of phase with the signal, and becomes a large positive feedback. Nobody ever talks about the time and frequency stability of the climate system.
kadaka (KD Knoebel) says:
May 27, 2012 at 10:25 pm
As to the rejection of Clive Best’s paper, could it be because he used degrees Kelvin?
What should he have used? Fahrenheit?
From Leif Svalgaard on May 28, 2012 at 12:28 am:
Just plain kelvins, the unit. It’s been awhile, but that was drummed into me long before I got my physics bachelor’s degree, there are no degrees Kelvin. So I know you should be well aware of the distinction. You ever do a paper with “degrees Kelvin”?
There was also the inconsistency of using “K⁻¹” without the degree symbol (see Abstract and elsewhere), or simply “K” (the equation before the Conclusion), and also the lack of the symbol in the title of Figure 1 and elsewhere when “288K” was used, that indicates he should have known better.
Actually, when I think about it, the mix of notations gives the appearance of more than one mind working on it. Perhaps there was another author involved, or there was some amount of cut-and-paste, whatever it was. Good proofreading by a knowledgeable person should have caught it, at least made the usage consistent.
The use of °C for Figure 4 is allowable, as that’s what CRUTEM4 uses. But how can the rest of the paper use Kelvin otherwise, except for the Conclusion which is suddenly in °C? How could a single author do that?
This was submitted to the “prestigious” Geophysics Research Letters, which gets lots of more-polished submissions thus would have no reason to bother with it further. If I was an editor at a much-smaller journal, and considered the content interesting and I could simply remove the erroneous “degrees” from the text, I might do so, consider unifying to only kelvins as possible, and send it through the review process.
Yet the graphs also need correcting, there are the attribution questions, etc. Don’t get me wrong, it’s a great blog post, very informative. But as an editor, I would at least want this to look more professional before putting in the effort of getting it reviewed and maybe published. As professional as it should have been when it was sent to me in the first place.
To anyone reading this, feel free to continue talking about the publishing embargo against climate skepticism, which is real enough. What I’m pointing out is for this paper there are valid reasons to reject it regardless of content. Discussing the often-blatant discrimination against skepticism seems pointless to me with regards to this paper, when it is currently unpublishable anyway due to its amateurish style and presentation problems.
LS;
It’s improper use of the term “kelvin”.
1. In the International System of Units, the base unit of thermodynamic temperature; 1/273.16 of the thermodynamic temperature of the triple point of water. Shown as “K”.
2. A unit interval on the Kelvin scale.
3. The interval between the freezing and boiling points of water is 100 kelvins.
(usually as postpositioned adjective) A unit for a specific temperature on the Kelvin scale.
a) Ice melts above 273.16 kelvin.
b) Water boils above 373.16 kelvin.
The word “degrees” is redundant with kelvins; one may say 100 degrees Fahrenheit, or 100 degrees Celsius, but 100 kelvin.
OK agreed it should really be K and NOT deg.K. However the paper must use both deg.C and K because all calculations using Stefan Boltzman are in K, while all CRUTEM4 data is in deg.C. Since 273.15K = 0 deg.C , the rounding error converting K to deg.C by approximating 273K to be 0 deg.C is minuscule compared to measurement errors.
Sorry, reproduced the numbering above incorrectly:
1. In the International System of Units, the base unit of thermodynamic temperature; 1/273.16 of the thermodynamic temperature of the triple point of water. Shown as “K”.
2. A unit interval on the Kelvin scale.
——The interval between the freezing and boiling points of water is 100 kelvins.
3. (usually as postpositioned adjective) A unit for a specific temperature on the Kelvin scale.
a) Ice melts above 273.16 kelvin.
b) Water boils above 373.16 kelvin.
GES;
Kinda pit-nicky today! You’re too hard on Robert; the best analogy for the GE is DC positive feedback. Close enough for government work, which it is.
Oh, by the way, could you explificate a bit more about these very intriguing radios using “positie” feedback? Sounds downright cutsie!
And I didn’t realize you were so religious!
Are you conflating Christ and Ra?
kadaka (KD Knoebel) says:
May 28, 2012 at 2:48 am
“What should he have used? Fahrenheit?”
Just plain kelvins, the unit
Being picky today eh? We used ‘degrees Kelvin’ up to about 1968. After it is ‘kelvin’ without the ‘s’..
But even so, the ‘degrees Kelvin’ is still around, e.g. in: http://csep10.phys.utk.edu/astr162/lect/cosmology/cbr.html
http://eesc.columbia.edu/courses/ees/climate/lectures/radiation/
http://www.sciencedaily.com/releases/2006/03/060308212104.htm
It seems overly pedantic to disallow ‘degrees’. Even the well-known text books http://www.amazon.com/Essentials-Meteorology-Invitation-Atmosphere-CD-ROM/dp/0534372007
uses ‘degrees Kelvin’.
kadaka (KD Knoebel) says:
May 27, 2012 at 10:25 pm
As to the rejection of Clive Best’s paper, could it be because he used degrees Kelvin?
Leif Svalgaard says: May 28, 2012 at 12:28 am
What should he have used? Fahrenheit?
_______________
Good question Leif – I too was wondering about this.
I had forgotten about degrees Rankine.
Apparently there are also degrees
Delisle
[°De] = (100 − [°C]) × 3⁄2
Newton
[°N] = [°C] × 33⁄100
Réaumur
[°Ré] = [°C] × 4⁄5
Rømer
[°Rø] = [°C] × 21⁄40 + 7.5
Not to mention Goode Olde Englishe units – how about something involving hogsheads or firkins?
Not to forget the gill, drachm, minim, spoon, pin, peck, kilderkin, barrel, puncheon, tun, butt, cord, rick, fathom, and my personal favorite, the Hoppus foot.
Apparently, in Scotland, 2 mutchkins = 1 chopin. Who knew?
Can anyone tell me if the faint sun paradox takes into consideration the initial specific heat of the earth, it’s initial temp, the fluid dynamics of a mostly molten ball of iron and rock, and given the much higher density atmosphere (and our complete ignorance of same), how much such a system would cool in a billion years with no solar insolation whatsoever ?
Mike Wryley says:
May 28, 2012 at 6:50 am
Can anyone tell me if the faint sun paradox takes into consideration the initial specific heat of the earth, it’s initial temp, the fluid dynamics of a mostly molten ball of iron and rock, etc…
Yes, scientists are not morons and the review I linked to goes through the various factors.
Stephen Wilde says:
May 26, 2012 at 11:42 pm
Liquid oceans for 4 billion years despite huge volcanic outbreaks, asteroid strikes, changed atmospheric density and composition and a substantial change in the output of the sun.
The only solution is a strongly negative water cycle response to ANY disruption to the system.
I agree, only a strong negative feedback really holds water in resolving the dim sun paradox. CO2 is a non-starter as it has fluctuated wildly with no credible relationship with temperature, e.g. snow-ball earth ice-ages during CO2 concs >10k ppm. (While very loosely one can say CO2 has declined over the earth’s history, there have been periods of hundreds of millions of years where temperatures and CO2 levels were moving in opposite directions, e.g. around the Silurian-Carboniferous.) Other factors such as ocean cover, volcanism, require a gradual change precisely calibrated by pure chance to exactly counter the increasing insolation. Not credible.
As other posters have pointed out, the major point here is that AGW needs a positive water feedback which can be shown not to be credible. CAGW was formulated with a narrow, blinkered focus on the second half 20th century, ignoring any previous climate history. Their palaeoclimate defences have been awkwardly bolted on later.
Water vapour in the atmosphere is acknowledged by most to be dominant in the atmosphere’s thermal dynamics. If this dominant component were characterised by positive feedbacks, then the whole climate system would be hugely unstable – and it is not. So the formulation of the AGW theory has been not only in willful ignorance of palaeoclimate history, but also sterile of any appreciation whatsoever of nonlinear system dynamics. They just dont understand the consequences of their assertion of dominant positive feedback.
In a non-equilibrium/nonlinear quasi-chaotic system such as the earth’s atmosphere-oceanic climate, if positive feedbacks are dominant then they suppress complex emergent structure (nonlinear pattern formation) and impose monotonic oscillation. (The heart-beat is an example of this.) Since climate does not oscillate monotonically – but in a complex and modulating way – then it is clear that positive feedbacks are not dominant. Negative feedback, otherwise called damping or dissipation, lead to the emergence of complex fractal structure. So the fleeting appearance of oscillations in an overall complex jumble with fractal characteristics point to a tension between positive and negative feedbacks.
In short, its impossible for the earth’s stable and robust – while at the same time complex and fractal – climate system NOT to be damped. And the evidence is strong that atmospheric water is doing the damping (negative feedback).
Crispin in Waterloo says:
May 27, 2012 at 12:56 pm
@Larry Plume P.
“The Mantle of the Earth is said to contain about twice as much water as the oceans. Could it be that it simply sunk into the mantle over time until it was ‘balanced’? It is very possible that we were ‘Water World’ in the early days.”
Crispin, Pope and colleagues – in the article that I linked – found out that the isotope ratio of deuterium to normal hydrogen changed during the ages and this ratio change can be explained through methanogenesis (two-stage process, water and carbon dioxide react to form methane, and subsequently hydrogen – see above link) which favours hydrogen to deuterium.
In this explanation doesn’t matter how much water did flow in the mantle it does not explain the ratio change. It does not exclude the water flow into the mantle but is an indicator of very probable water decomposition and hydrogen flow into space.
Probably the oxygen has been then bounded to other minerals and in my view may also explain why oxygen appeared relative early in the history, but this is only speculation on my side.
“”””” In a non-equilibrium/nonlinear quasi-chaotic system such as the earth’s atmosphere-oceanic climate, if positive feedbacks are dominant then they suppress complex emergent structure (nonlinear pattern formation) and impose monotonic oscillation. (The heart-beat is an example of this.) Since climate does not oscillate monotonically – but in a complex and modulating way – then it is clear that positive feedbacks are not dominant. Negative feedback, otherwise called damping or dissipation, lead to the emergence of complex fractal structure. So the fleeting appearance of oscillations in an overall complex jumble with fractal characteristics point to a tension between positive and negative feedbacks. “””””
Sorry; negative feedback doesn’t have a thing to do with damping or dissipation; they are totally different and unrelated subjects. You can demonstrate the effect of damping or the lack thereof, in a complete absence of ANY feedback; whether positive or negative. I will grant you that “dissipation” is a rather imprecise colloquialism for damping.
If you apply a step function from a zero source impedance source, to a series connected inductor, and capacitor combination; or their analogs in some other discipline, you WILL get an oscillation, which theoretically will persist forever (in classical Physics, anyway). Ther’s not a whit of feedback anywhere in that system, so one can’t even talk about positive or negative; it is zero.
But in practice; no source actually has zero source impedance, and no inductor or capacitor has zero resistance component; maybe at superconducting Temperatures, they can have zero R.
So the inclusion, accidently or deliberately of some resistance; which IS an energy dissipative element, will gradually dissipate some of the energy, which is being transferred back and forth between a Voltage across the capacitance, and a current through the inductance Ppower is lost at the rate of I^2.R.
When talking about climate elements, and feedbacks, it is wise and instructive, to consider the following simple fact.
There is NO SUCH THING as a an electronic amlifying system, which makes a practical usage of feedback; either positive or negative; where such amlifying system; prior to the connection of feedback networks, HAS A POWER GAIN OF LESS THAN UNITY. ALL such systems start with an input to output POWER GAIN, that is greater than 1, and usually VERY MUCH GREATER THAN ONE, before any feedback networks are added. Those feedback networks, will result in a reduction of the final system power gain. They do that without necessarily DISSIPATING any power in the process, although dissipation of small amounts of power is not prohibited.
So what about the climate system. Starting with an input signal from the sun, and for the moment excluding all GHGs from the atmosphere; just WHAT in the earth climate system has an input to output power gain, GREATER THAN ONE.
Well there is nowhere in the system where you ever see an “output” signal power, that is GREATER THAN TSI.
So talking about feedback in relation to climate, is total nonsense. There is no amlifying structure in in with a power gain in excess of one. One consequence of the absence of a positive power gain, anywhere in the climate system, is that there also cannot be any positive power gain involved in ANY feedback network; so both the forward, and feedback power gains for any feedback loop you want to create out of the climate system elements, are ALWAYS less than unity. Consequently the LOOP GAIN, which is the product of the forward, and feedback power transfer functions, can never reach; let alone exceed unity.
Ergo, it is inherently impossible; no matter what, for such a system to oscillate in any runaway mode.
Lief,
With all due respect, the incidence of morons within the scientific community is at least as high
as within the general population.
And your link does not work
4 billion years ago, the sun was heavier than it is today, which would have made the earth’s orbit smaller. Being closer to the sun would help to compensate for the sun being dimmer. Also the tidal affect between the earth and the sun would have added a few miles to the earth’s orbit over that time period.
As to the amount of water on the earth back then. The earth is still comets of varying sizes, from dinosaur killers to micro. I would assume that 4 billion years ago, the rate of impact would have been higher, gradually decreasing to today’s rate. Over 4 billion years, that’s a lot of water.
George E. Smith; says:
May 28, 2012 at 9:02 pm
“”””” In a non-equilibrium/nonlinear quasi-chaotic system such as the earth’s atmosphere-oceanic climate, if positive feedbacks are dominant then they suppress complex emergent structure (nonlinear pattern formation) and impose monotonic oscillation. (The heart-beat is an example of this.) Since climate does not oscillate monotonically – but in a complex and modulating way – then it is clear that positive feedbacks are not dominant. Negative feedback, otherwise called damping or dissipation, lead to the emergence of complex fractal structure. So the fleeting appearance of oscillations in an overall complex jumble with fractal characteristics point to a tension between positive and negative feedbacks. “””””
Sorry; negative feedback doesn’t have a thing to do with damping or dissipation; they are totally different and unrelated subjects. You can demonstrate the effect of damping or the lack thereof, in a complete absence of ANY feedback; whether positive or negative. I will grant you that “dissipation” is a rather imprecise colloquialism for damping.
If you apply a step function from a zero source impedance source, to a series connected inductor, and capacitor combination; or their analogs in some other discipline, you WILL get an oscillation, which theoretically will persist forever (in classical Physics, anyway). Ther’s not a whit of feedback anywhere in that system, so one can’t even talk about positive or negative; it is zero.
Your definition of feedback may be a little restrictive – you are looking only at electrical circuits. Feedback can be meant more widely as anything which is a consequence of a forcing agent in a system which sets in motion processes which eventually act to either reinforce (positive feeback) or resist (negative feedback) the initial forcing agent. In this sense simple friction is a negative feedback – increasing road speed in a car results in increased friction both in air and at the road surface so that friction resistance increases with speed. Eventually friction equals accelerating force and the car reaches equilibrium speed.
So talking about feedback in relation to climate, is total nonsense.
This is quite a bold statement when the majority of climate scientists on both sides of the AGW fence repeatedly assert that the CENTRAL question in climate is the magnitude and sign of feedbacks. I think this is a question of terminology – different disciplines use the term feedback differently. “Climate science” as has been explained before, is not really a field in its own right, it lives parasitically off oceanography, radiative and optical physics, geology, solar physics, ecology, geosciences and several other disciplines.
I (unlike you) am no engineer. This means I am not best placed to really get to grips with these issues of nonlinear dynamics since it is within certain fields of engineering where understanding of nonlinear system dynamics is strongest and best developed – in my view chemical engineering is foremost among these.
Thus although trying to sound knowlegable in these things, I am discussing work and theory that I only partially understand at best. But I would still bet my house (flat) or car that I am right – in the general sense that the nonlinear / nonequilibrium system paradigm is the right one for climate. Why? Because it “feels” compelling and appropriate. That might sound crap, but sometimes in nonlinear chaos-like systems its the best you can hope for – until someone fully works out the science of it. The experimental system that I am thinking of primarily in relation to the role of feedbacks in nonlinear pattern formation is the one much used in this context, the platinum-catalysed oxidation of CO under the influence of chemical feedbacks regulated by gas pressures, and specifically the spatio-temporal patterns formed on the crystal surfaces. (This is what happens in your car’s catalytic converter.) Two papers describing it are (unfortunately paywalled):
Science 18 May 2001:
Vol. 292 no. 5520 pp. 1357-1360
Controlling Chemical Turbulence by Global Delayed Feedback: Pattern Formation in Catalytic CO Oxidation on Pt(110)
Minseok Kim, Matthias Bertram, Michael Pollmann, Alexander von Oertzen, Alexander S. Mikhailov, Harm Hinrich Rotermund* and Gerhard Ertl
http://www.sciencemag.org/content/292/5520/1357.short
APPLIED PHYSICS A: MATERIALS SCIENCE & PROCESSING
Volume 51, Number 2 (1990), 79-90,
Nonlinear dynamics in the CO-oxidation on Pt single crystal surfaces
Ralf Markus Eiswirth, Katharina Krischer and Gerhard Ertl
http://www.springerlink.com/content/j587322461531360/
One of these authors, Matthas Bertram, with whom I have corresponded on these issues, used to have his excellent PhD thesis online, which is a rich source of explanation and experiemental plus mathematical work on chaos, turbulence and spontaneous pattern formation, from the field of chemical engineering. Sadly he took it down. If you are interested I can upload a copy of it.
It is this Pt 110 crystal catalysed CO oxidation system that shows very clearly that (a) negative feedbacks in the system stimulate spontaneous pattern formation (all nonlinear pattern formation needs a dissipative element – here again I am loosely associating dissipation with negative feedback, but I’m not alone in doing so) and that (b) introducing positive feedback “kills” the more fecund and complex pattern formation and imposes more uniform and monotomic oscillation. What is most compelling from the climate perspective is that you get this scenario of tension between the positive and negative feedbacks resulting in complex nonperiodic pattern but with periodic uniform oscillation intermittently and partially manifesting in the system. This looks a lot like climate temperature series.
Ian W says
“The paper should be assessing the heat content in kilojoules. Temperature alone is meaningless and the incorrect metric for heat content.”
You need to speak to the IPCC about that. In order to speak the same language as the IPCC and avoid comparing “apples to oranges,” we are forced to evaluate climate not only in terms of temperature but globally-averaged temperature.
“”””” re phlogiston Your definition of feedback may be a little restrictive – you are looking only at electrical circuits. “””””
No I am not looking only at electrical circuits; I simply gave an electrical analogy, which is among the easiest to understand for non experts. How many different examples of feedback would it take for you to see, my description is not at all restrictive. If I gave examples from 50 different classes of physical systems, would that be enough to show lack of restriction, or should I give perhaps 100 ?
By the way, virtually all physical systems are bidirectional; twoports being the simplest to understand. They have both forward, and backward transfer functions, and traditionally the forward direction is commonly regarded as the direction in which there is a net power gain.
The mathematics of feedback networks, is not at all restricted to any one physical implementation; they can be mechanical, hydraulic, optical, and on and on. What you are calling feedback is little more than the natural cause and effect relationship, including time delays.
When you toss a rock into a pond; lots of physical cause and effect relationships are activated. Waves spread out from the rock, the rock meanders down to the bottom, where it will collide with what is there which might happen to be a scuba diver. Eventually all those consequent effects will settle down. That is NOT feedback operating, it is simply the finite propagation delay of physical phenomena.
George E. Smith; says:
May 30, 2012 at 1:48 pm
I’ll keep an eye open above me for falling rocks next time I go scuba diving.
With so much talk of feedbacks it is indeed necessary to clarify definitions of what is feedback and what is not.
The PhD thesis of Matthias Bertram that I mentioned can be downloaded here.
Here is a quote from it [page 27, section on global feedback]. I boldened the word “information” since here Bertram brings in an interesting and important aspect of feedback (he is talking about delayed feedback) – that it is an information signal. So feedback is not just about power/energy, it is about information also.
3.2 Global feedback
3.2.1 Overview of feedback schemes
Feedback techniques differ from periodic forcing by the fact that the control signal is not fixed a priori, but an acting force is generated by the system itself. Feedback techniques were originally designed for the control of chaos in dynamical systems with only a few degrees of freedom [96–99], but were later extended for the application to high-dimensional systems governed by partial differential equations [36, 63–71].
In global feedback methods, information continuously gathered from all system elements is summed up and used to generate a control signal which acts back on a common parameter that affects the dynamics of the entire medium. Such a feedback loop can be easily implemented into many experimental systems, and does not require the knowledge of the governing equations. The action of global feedbacks on chaotic extended systems has been recently investigated experimentally for arrays of electrochemical oscillators [100], and theoretically for semiconductors [38] and surface chemical reactions [101, 102]; effects of global feedback also have been discussed in the general context of the complex Ginzburg-Landau equation [36, 37]. Furthermore, various forms of global feedback have been successfully applied to control pattern formation in non-chaotic oscillatory [41,103,104] and excitable [105–109] chemical systems.
Some climatic or oceanographic phenomena set in motion processes which take years to run their course. For instance, an El Nino event generates a pool of equatorial warm water which then migrates anticlockwise around the Pacific basin for several years, warming the Arctic up to a decade later. Changes induced in cold water downwelling – say at the Norwegian sea – could have effects on ThermoHaline Circulation at even longer times in the future. Could such delayed “signals” act as feedback signals in the sense that Bertram is describing in the various experimental systems?
OK so killing the bold killed the italics also. The Bertram quote extends to “and excitable [105-109] chemical systems”. After that it’s me again.