Guest Post by Willis Eschenbach
On another thread, a poster got me thinking about the common practice of using the El Nino 3.4 Index to remove some of the variability from the historical global average surface temperature record. The theory, as I have heard it propounded, is that the temperature of the Earth is “signal”, whereas the El Nino cycles are natural swings and as such are just “noise”. So if you remove the El Nino swings from the temperature, the theory goes, then we can see more of the underlying temperature signal by removing the noise.
Figure 1. Various “Nino regions” used in the study of the El Nino / La Nina phenomenon. Each area has its own index, with one of the most commonly used being the Nino 3.4 Index. SOURCE. See also the NOAA page
The more I thought about the practice of subtracting the Nino 3.4 variations from the global average temperature anomalies, the more questions came up for me. I don’t have the answers, hence this post. The first question that came up is, how do we decide that the Nino 3.4 Index represents noise instead of signal?
The Nino 3.4 region covers about 2.4% of the planet’s surface, a bit bigger than the USA. So … why isn’t the temperature of the USA “noise”? Or perhaps, is the temperature of the US “noise” but no one ever checked? And how would you check? What mathematical procedure would allow us to discriminate? What test would we use to say well, Nino 3.4 is noise so we can safely subtract its effects from the global temperature signal, but, for example Nino 1+2 is not noise, it’s part of the signal?
My next question about the situation revolves around the fact that the Nino 3.4 Index is merely a linear transform of the sea surface temperature of the Nino 3.4 area. So what we are doing is taking a linear transformation of the surface temperature anomaly in one part of the world, and subtracting it from the global average surface temperature anomaly.
As a result the question is, is this a legitimate operation? Subtracting a linear transform of something from the whole of which it is a part? Like, say, taking the average temperature variations in the whole US including Texas, but then subtracting out some linear transform of the temperature variation in Texas? What is the meaning of that procedure, subtracting something from itself? And if we are going to subtract a transform of say the Nino 3.4 temperature from the global average, should we include the Nino 3.4 temperature to begin with when we calculate the global average, or not?
Next question is, is this a legitimate operation in a system with a thermostat? Like for example, taking the variations in my body temperature, but subtracting out some linear transform of the temperature variations in my foot? What does that procedure give us, what does the result mean?
Next question. If we’re going to remove the transform of the El Nino Index from the global average temperature record, then should we remove the other indices as well? Should we remove the AMO (Atlantic Multidecadal Oscillation) Index? The PDO (Pacific Decadal Oscillation) Index? The Madden-Julian Oscillation Index? Some combination of them? All of them?
Final question. From my perspective, the El Nino/La Nina oscillation actively regulates heat loss, and thus is part of the planetary temperature regulation system. It regulates the heat loss by way of both the ocean and the atmosphere. Let me give a functional explanation of how it works. The explanation is slightly but not significantly simplified.
During La Nina conditions, in the upper part of Figure 2 below, the warm blanket of water normally covering the Pacific has been blown to the west by the strong eastern trade winds. From there, that mass of warm Pacific surface water splits and moves north and south along the coasts of Asia and Australia towards the Poles. The mass of water is radiating and losing heat as it travels. Functionally, the El Nino/La Nina alteration serves as a huge, slow-cycling, thermally regulated Pacific-wide pump. The La Nina pump stroke moves warm Pacific surface water poleward to lose its heat through conduction, radiation, and evaporation.
Figure 2. La Nina and El Nino conditions. North and South America are the brown areas in the upper right. Australia is at the lower left. Black arrows in the atmosphere show the direction of atmospheric circulation. White arrows show surface ocean currents SOURCE: NOAA El Nino Theme Page
In addition to moving warm Pacific water poleward, the removal of the warm Pacific tropical surface waters exposes the atmosphere to huge amounts of cooler sub-surface Pacific water. This lowers the air temperature over that whole area of the tropical Pacific. Soon, however, the surface of the Pacific starts to warm again. One effect of this is that it slows down the eastern trade winds. As a result of reduced winds and reduced clouds, the warming of the surface of the Pacific continues. In addition, some of the warm surface water in the Western Pacific moves back out east. Soon, with the sun beating down on an ocean with reduced clouds, it warms up all across the Eastern Pacific. This leads to neutral conditions, which can last a while.
However, if the tropical Pacific surface temperature warms enough, then El Nino conditions develop. After the El Nino conditions come into being, at some point as the surface of the Pacific continues to warm, and the El Nino thunderstorms drive the surface air upwards, the eastern trade winds start to strengthen. Soon the eastern trade winds start pushing the warm tropical surface waters and their associated thunderstorms and clouds to the west across the Pacific and eventually poleward again. This is the power stroke of the pump, when the trade winds strip the warm surface waters off and push them westwards. In this process, the full La Nina conditions come into existence. Finally, the La Nina conditions eventually peter out to a neutral condition once again.
Note that this system is triggered by temperature. If the temperature doesn’t build up across the surface of the eastern Pacific for some reason, then things stay neutral, neither El Nino or La Nina. In that case, the El Nino doesn’t form, and so the eastern trade winds don’t build up to pump the warm water across the Pacific and towards the poles.
But when the surface waters of the Pacific do heat up beyond a certain point, El Nino conditions arise, the eastern trade winds strengthen and pump the warm tropical surface water, first across the Pacific and then to the poles. It also exposes the atmosphere to a large area of cooler subsurface water.
Note the effect of this amazing temperature regulating heat pump. It functions to prevent any long-term buildup of heat in the waters of the surface Pacific. If the water in the surface of the Pacific stays cooler, the heat pump doesn’t kick in. But as soon as a certain amount of heat builds up in the surface Pacific waters, the El Nino/La Nina alteration occurs, pumping the surface water west to be flushed out toward the poles. The layer of warm surface water that was blown west is then replaced by cooler water from the subsurface, cooling the entire tropical Pacific.
This mechanism, this El Nino/La Nina pump skimming off the hot Pacific water and pumping it to the poles, prevents long-term Pacific heat buildup and thus actively keeps the planet from both overheating and excessive cooling. It is one of the many interacting thermoregulating mechanisms that keep the earth from either overheating or becoming too cool.
So … this brings up the final question regarding the theme of this post.
Since the variations in the Nino 3.4 index are indicative of the functioning of one of the Earth’s major thermoregulating mechanisms, namely the giant El Nino/La Nina pump that magically materializes to move warm tropical Pacific water to the poles whenever the planet gets too hot and sweaty … then under what possible construction could the Nino 3.4 Index variations be called “noise”?
Like I said … lots of questions, I don’t have the answers, all courteous contributions welcomed.
Regards to all,
w.
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Phil says:January 17, 2013 at 12:22 pm
Several climate scientists note that 90% of AGW warming is going into the oceans. In reality, we can almost neglect what is happening in the atmosphere, and just look at the temperature of the ocean.
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Does not compute. Water is opaque to IR radiation. The claim “that 90% of AGW warming is going into the oceans” is the worst sort of junk science.
rgbatduke says:
January 17, 2013 at 9:29 am
“And we will never succeed in doing so at the same time we make energy more expensive and discourage its use. The poverty in question is energy poverty. Fundamentally. With enough, cheap enough, energy, we can make the deserts bloom, create jobs in the heart of Africa or India or South America, bring medicine and electric lights and running water to the world. Cheap, clean energy solves all problems; it is the fundamental scarcity.”
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True. But the goal isn’t to control the energy. It’s to control the people that need that energy.
Dear Willis, I like your articles and I am going to comment on an area about the energy in the ocean that everyone overlooks. I hope that you will look into my comments. There are many chemical reactions in the ocean that are mostly endothermic, although a few are exothermic. I looked into this after your post about a year ago on the Argo float temperatures and how the ocean generally does not heat above 30 degrees C. My knowledge of chemistry is limited; but, I noted these things: Carbon dioxide as well as other gasses in water act like a liquid. If you check the phase diagram for carbon dioxide, you will find that it cannot exist as a liqud at temperatures above 30.3 degrees C. You can heat water to 30 degrees and see the bubbles of gas forming on the side of the container. When the ocean reaches 30.3 degrees, the carbon dioxide changes to a gas and bubble toward the surface. On its way it bubbles through a saturated solution of Calcium oxide. The commerical method of preparing Calcium carbonate is to bubble carbon dioxide through a saturated solution of calcium oxide heated to 40 degrees C. The reaction of the carbon dioxide and Calcium oxide removes approximately 1200 kilo joules of energy from the ocean for each mole of calcium carbonate formed. This is the reason that the ocean does not generally heat above 30.3 degrees.
The calcium carbonate formed is not soluble at the temperatures and pressures found at the surface of the ocean. But as it descends into the ocean depths, it is dissolved. This process is called hydration and occurs when H2O molecules attach themselves to the calcium carbonate. I have forgotten the values for the heat of hydration, but they are similiar to the values in the original reaction. The energy is taken from a cold ocean and occurs when the reactants can find sufficient energy for the reaction to occur. This is one of the reasons that the bottom of the ocean and deep lakes are very cold.
Now we are getting to your current article. The hydration reaction can be reversed. When currents in the ocean bring the hydrated calcium carbonate back to near the surface, the heat of hydration is released and warms the top layers of the ocean. This process is like a heat pump. It appears to violate the second law of thermodynamics, but it does not since thermal energy is changed to chemical energy and back to thermal energy. There was an article about 1-2 years ago where two NOAA researchers were noting that it was not well understood why the intermediate levels of the ocean did not heat up.
I do not know just how these processes work together to produce the results that you see, but I hope that you use this information to put a total picture together.
Some speculation about other processes; there is a possibilty that the ocean on occassion may freeze and produce fraggle ice flows that help to bring the hydrated calcium carbonate to the surface. The presence of carbon dioxide and ice in water can produce formic acid and may be the source of the corrosive upwelling water that has been reported by Hansen and others.
John Owens
Greg Goodman says:
January 17, 2013 at 10:56 am
“ . . . the colder waters surface of Peru suggests to me an upwelling of water striking the massive underwater mountain that is South America.”
You might want to investigate things “Ekman” – layer, transport, spiral.
http://oceanworld.tamu.edu/resources/ocng_textbook/chapter09/chapter09_04.htm
An image search is also helpful.
“Noise” is the part of the phenomenon under study that your theory can’t explain.
A correction to my post. It is calcium hydroxide that reacts with carbon dioxide to form calcium carbonate.
How about those 30 year heat waves that seem to precede the grand minimums? The graph from the JG/U tree ring study along with a new tree ring study that just came out show that prior to the Dalton minimum in 1790 there was a 30 year near record setting heat. Then 30 years prior to the Maunder minimum there is record setting temperatures that slide into minimum about 1625. The JG/U chart shows the 1470 minimum. Just prior to that is 25 years of a heat wave. The next one back is around 1300. There are 30 years of a heat wave prior to that. Then about 1120 the same pattern holds true. The second graph that I am looking at is the eastern Europe tree ring study that recently was published. We just had 30 years of a record heat wave. What is the likelihood of a grand minimum?
rgbatduke says: Al Gore is just like a Baptist minister who is all hellfire and damnation when it comes to public drinking but who gets regular deliveries from his local moonshiner just the same.
Very good analogy. Gore is the green version of the TV evangelist preacher.
John F. Hultquist says:
January 17, 2013 at 9:44 pm
Greg Goodman says:
January 17, 2013 at 10:56 am
“ . . . the colder waters surface of Peru suggests to me an upwelling of water striking the massive underwater mountain that is South America.”
You might want to investigate things “Ekman” – layer, transport, spiral.
http://oceanworld.tamu.edu/resources/ocng_textbook/chapter09/chapter09_04.htm
Thanks John, I was aware of Ekman transport which really only tells us the unexpected direction of which way water moves when blown. Clearly is surface water moves some non surface water is exposed. That does not imply it moves the thermocline, which was my point and what was shown in Willis’ figure 2 that I refered to.
The page you refered me to ends with this:
“… and vertical velocity at 23 m depth was concentrated in narrow jets under the areas of surface convergence (Figure 9.6). Maximum vertical velocity was -0.18 m/ s. The seasonal thermocline was at 50 m, and no downward velocity was observed in or below the thermocline.”
Now El Nino/Nina is shown as an ocean wide tilting of the the thermocline. The link you gave gives me more reason to be doubtful that this is the result of surace winds.
Of course any information is useful, so thanks again.
Arno Arrak: But any wave that runs ashore must also retreat. As the El Nino wave retreats sea surface behind it is lowered by half a meter, cool water from below wells up, and a La Nina has started.
You are saying that the Nino wave has to flow back by gravity as any wave. That would mean normal level water is left behind and does not give a reason for “up-welling”.
Your comments about “waves” seem to be based on temperature observations,ie they are temperature waves not volumetric waves. Is there any altimetry data to show how mean sea level varies along the peruviean coast during these events?
Philip Bradley says:
January 17, 2013 at 2:20 pm
While I’ve never seen this properly articulated, I can answer your first question, which is really about what is signal and what is noise?
The theory is that net forcings drive atmospheric temperatures (ignoring diurnal and seasonal variations). Absent natural variability, atmospheric temperatures would be a direct function of net forcings with minimum lag.
The signal is the direct and (almost) immediate effect of net forcings. Everything else that affects atmospheric temperatures is noise.
Removing ENSO variability is an attempt to remove what is believed to be a major source of natural variability and so get a clearer picture of the forcings signal.
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That is exactly the problem that I think Willis is trying to draw attetion to. The very act of calling something “natural variability” is being used to make an implicit assumption that it is an independant , mean zero process.
That is totally unjustified and arbitrary without proof.
El Nino and La Nina are _opposing_ effects but the heat transfer is each case is very different. This is not just the two phases of a symmetric process.
In the absence of sufficient understanding to model these effects there is a willfil attempt to ignore them by assuming (incorrectly) that they are necessarily mean zero oscillations.
If, as Willis suggests, they are acting as negative feedbacks which make a significant contribution to the stability of the climate system (and it has proved to be remarkably stable to massive changes in conditions historically) then incorreclty assuming it is a random, mean zero process will lead to incorrect conclusions.
There is a certain amount of slight of hand going on when someone pretends that calling something “natural variability” is used as an excuse for not bothering to understand it before saying it does not matter and dismissing it as “noise”.
Greg Goodman says: “El Nino and La Nina are _opposing_ effects but the heat transfer is each case is very different. This is not just the two phases of a symmetric process.”
Well said. To expand on your comment: El Nino and La Nina can have opposing effects in some portions of the globe, but not all, and you’re right; El Nino and La Nina are not just opposing phases of a symmetric process.
First, regarding opposing effects, back in the 1970s and 80s, when meteorologists were studying the impacts of ENSO, they determined where and when temperatures and precipitation consistently varied in response to El Nino and La Nina events. Typically displayed as such:
http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ensocycle/elninosfc.shtml
They were looking for similarities in patterns to help make weather forecasts. They were not looking for differences, or for areas where El Nino and La Nina could have cumulative effects.
Because La Nina and El Nino act as a recharge-discharge oscillator, they are definitely not simply opposing phases of a symmetric process. Sunlight provides the energy for the recharge during La Nina, and the El Nino discharges (releases and distributes) it as warm water.
While I’ve never seen this properly articulated, I can answer your first question, which is really about what is signal and what is noise?
The theory is that net forcings drive atmospheric temperatures (ignoring diurnal and seasonal variations). Absent natural variability, atmospheric temperatures would be a direct function of net forcings with minimum lag.
The signal is the direct and (almost) immediate effect of net forcings. Everything else that affects atmospheric temperatures is noise.
Dear Phil,
Words fail me. The atmosphere is one of four distinct thermal reservoirs — land surface, ocean, the atmosphere, and ice. Each of these reservoirs is structured — the atmosphere has vertical structure as well as transverse structure, and its structure ranges from persistent but variable (e.g. Hadley) to transient and chaotic self-organized structures on many scales (high and low pressure systems that dominate weather, hurricanes, and includes the global decadal oscillations — that is, time scales from hours to decades (at least) are clearly represented.
The ocean is similarly vertically structured with a highly inhomogeneous surface temperature distribution with significant annual variation down to a highly homogeneous temperature distribution at depth. It, too has significant transverse structure and is a global transporter of heat as complex currents move water around based on its temperature, salinity/density, wind direction at the surface, heat sources at depth, evaporation, the coriolis force, the shape of the ocean bottom, and freshwater contributions from e.g. rivers and melting ice. Its relevant timescales again range from days to centuries, and it is strongly coupled to the atmosphere almost everywhere the two are in direct contact.
The land surface is laterally structured with widely differing albedo, and vertically structured so that it intercepts the vertically structured ocean and atmospheric reservoirs at different heights, hence different local mean temperatures. It’s vertical structure has a pronounced and permanent dynamic effect on both of the fluid reservoirs, as e.g. moisture precipitates out on western ocean-facing mountains leaving dry air and often desert conditions to the east of them — and much more. The water content of the surface is an important semi-stable feedback mechanism so that places like the Sahara are self-sustained as desert but could as easily be planted with water-retaining plants and completely change its character, with timescales of variation from days to thousands of years, clearly coupled to things like human and biological forces, atmospheric and other climate variations, and more (and returning the favor).
Ice has a huge albedo compared to everything else, and represents an enormous reservoir of cold fresh water deposited on continent-sized chunks of the globe (not to mention winter snowfall in regions where it isn’t “permanent” and glaciers where it is). Since albedo is a direct factor in global insolation and much of the ice forms annually on top of ocean, ice has multiple effects, coupled at timescales ranging from days to millions of years.
The whole thing is on a tipped ball whirling around a variable sun with an erratically varying orbit with multiple timescales on the order of tens of thousands of years.
The complete set forms a non-Markovian nonlinear, coupled integrodifferential system with timescales stretching from minutes to millions of years. None of this is noise, it is all signal. None of this is separable. To even try to make a Markov approximation (which is basically what you propose) and extract the entire content of the integration over the past is absurd.
Seriously.
rgb
Here is a plot of change in length of day and El Nino region 1+2 [80-90W 0-10 S]
Both are scaled to their std deviation and reduced to have mean of zero. The LOD is plotted as rate of change (this represents the change of angular momentum which is what would cause a displacement of the ocean contents) and has been lagged by 1.4 to roughly align the data.
http://i49.tinypic.com/2u90k1d.png
Graeme W says:
January 17, 2013 at 6:56 pm
Bill Illis says:
January 17, 2013 at 1:27 pm
Going farther out, one would assume the ENSO will balance out to Zero as it has since 1871.
Bill, I’ve heard the assumption that ENSO will balance out to zero many times, but I’ve never seen the supporting evidence for that assumption. You’ve made the statement that it has balanced out to zero since 1871.
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It just means that therehas been no trend in the Nino 3.4 sea surface temperatures over time. It is 26.85C and there has been NO increasing or decreasing trend in that average over time. (Almost everywhere else on the planet has some trend, mostly increasing but not the Nino regions).
It does vary in a small seasonal cycle +0.85C/-0.4C and then it varies by +3.4C/-2.4C depending on the state of the El Nino/La Nina.
If you add up all those anomalies over time, it turns out to be close enough to Zero to be called Zero but maybe it would be better to say the Nino 3.4 region has stayed at 26.85C in the long-term and there will be a balance between El Ninos and La Ninas in the long-term. Maybe over a five year period there won’t be, and this has happened many times before, but in the long-term, they have balanced out / will balance out.
Nino1.2 vs LOD , using month data for a bit more accuracy the lag looks somewhat shorter. The correlation seems quite clear, in particular for the two major events. Sea temps were drawn from hadISST interpolated, filled in data set. Looking at some real data from those areas would alwo be interesting.
http://i47.tinypic.com/r0tp3c.png
Retired Engineer John says: January 17, 2013 at 10:42 pm
A correction to my post. It is calcium hydroxide that reacts with carbon dioxide to form calcium carbonate.
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the reaction I have seen given is HCO3(-) + Ca(++) —> CaCO3 + H(+)
the HCO3 derives from CO2 and HO(-)
mpainter says:the reaction I have seen given is HCO3(-) + Ca(++) —> CaCO3 + H(+)
the HCO3 derives from CO2 and HO(-)
I have seen a similiar formula in posts trying to explain corrosive ocean waters. All the chemistry texts and the descriptions given for the commerical production that I have seen give H2O as the by product. I think that writing the formula in that format is an attempt to mislead.
Bill Illis says: If you add up all those anomalies over time, it turns out to be close enough to Zero to be called Zero but maybe it would be better to say the Nino 3.4 region has stayed at 26.85C in the long-term and there will be a balance between El Ninos and La Ninas in the long-term.
What is this “balance” you are referring to? Again the key point is that this is not just an oscillation in one variable. There are two very different things happening in terms of energy budget in each phase.
La Nina causes more solar heat to be captured by the ocean, El Nino warms the atmosphere using this heat. If you are implying that because the ocean surface temperature does remains stable at 26.85C there is no change in OHC, then the long term effect is to pump heat into the atmosphere.
So it is not climate neutral. It is not a “balanced” or “internal” variation that can be ignored. Until there is understanding of the processes it can not reasonably be assume not to “matter”.
I can understand the net effect being zero in regard to global temperature, but I object strenuously to ignoring the immediate effects of El Niño/La Niña on CONUS temperatures and elsewhere, because it is quite apparent they influence temperature and precipitation.
This is not a post about Willis’s excellent questions, so if you’re not interested in word origins please skip to the next one.
HankHenry asked on January 17, 2013 at 8:31 am:
Anyone know the derivation of the word “jigger?” As in: “Someone has jiggered the numbers to make it work.”
Yes, after a minute or two with the OED. Jigger in this sense is a shortening of “jiggery-pokery” – a term with citations as early as the late 19th century, with the definition “Deceitful or dishonest ‘manipulation’; hocus-pocus, humbug.” In turn, jiggery-pokery comes from an earlier term “joukery-pawkery” (earliest citation 1686) made up of two fairly old words. Joukery (earliest cit. 1593) means “Dodging; ‘underhand dealing, trickery’; ‘deceit’” or “clever trickery, jugglery, legerdemain.” Pawkery, from pawk (earliest cit. 1513), means “Tricky, artful, sly, cunning, crafty, shrewd; esp. humorously tricky or sly.”
You inadvertently hit (one of the) the nail(s) on the head. Let us go with your 40 thermometers model…
Our warm waves head out from the ‘source’ and, a month later, hit the thermometers placed NE of the ‘source’. So, from peak El Niño conditions, we have a time delay for an impact on the Californian sensor (another 1/40th of the model) ‘surface temps’. So even with this ‘simple model’ we identify the problem of ‘time’. Only by fully understanding the relationship between peak in our ENSO region and Californian ‘weather patterns’ can we claim anything and even then probably not much.
Now what if, two years later, that El Niño starts to influence, by some as yet unidentified mechanism, the Winter weather of the UK. can we still just subtract the two? ( UK(this winter) – El Niño (two years earlier)). Willis (and Bob) make a fair point re simply subtracting the ‘inconvenient’ (and essentially unknown) forward effects of a massive event is imposible. The ‘event’ influences patterns years in the future – you just can’t subtract one from the other without considering ‘phase’ and only then when you have identified all those intervening ‘relationships’.
Describe the exact mechanism by which ENSO influences the monsoon season in India two years after the event? …. No me neither.
Greg Goodman January 18, 2013 at 2:34 am
That is correct about the Nino wave flowing back by gravity. When a Nino wave first runs ashore its kinetic energy of motion is converted into gravitational potential energy of the higher elevsation it has reached. It is this gravitational potential energy that is converted back into kinetic energy of motion of the departing wave. This parting wave leaves a vacuum behind it and sea level drops as a manifestation of this. You can think of it as the vacuum behind it sucking up the cold water from below. This is the physical aspect of ENSO. The temperature variations are variations in time synchronized to the physical motion of ENSO waves. If ENSO were a perfect harmonic oscillator the temperature curve would be a perfect sinusoidal wave train but in reality there are interferences in the ocean that can distort its path and with it the temperature curve. After all, it has to travel the width of the Pacific Ocean where lots of other things are also going on.
Greg Goodman says:
January 18, 2013 at 2:57 am
That is exactly the problem that I think Willis is trying to draw attetion to. The very act of calling something “natural variability” is being used to make an implicit assumption that it is an independant , mean zero process.
That is totally unjustified and arbitrary without proof.
El Nino and La Nina are _opposing_ effects but the heat transfer is each case is very different. This is not just the two phases of a symmetric process.
I wasn’t expressing an opinion on whether I thought the forcings theory and its predictions are correct or not. I was trying to explain what is signal and what is noise, as they are generally referred to in climate circles.
BTW, I agree with you on El Ninos and La Ninas.
rgbatduke says:
January 18, 2013 at 5:20 am
Articulate and lucid as always, but my understanding of the forcings theory (and the predictions out of the climate models) is that the internal complexity of the Earth’s climate doesn’t matter. If you know what the forcings are and their magnitude, you can predict whether the climate will warm or cool in the future and by how much, excepting the effect of natural variability (ie the internal variability of the climate system).
As I said above, I wasn’t expressing an opinion on whether this is correct or not. But this is the basis for the IPCC’s, etc predictions, and the ongoing debate about how long we can have no measured atmospheric warming and still maintain the theory, models and predictions are valid.
I hope I haven’t completely missed your point.