Guest Post by Willis Eschenbach
I see that Susan Solomon and her climate police have rounded up the usual suspects, which in this case are volcanic eruptions, in their desperation to explain the so-called “pause” in global warming that’s stretching towards two decades now. Their problem is that for a long while the climate alarmists have been shouting about about TWO DEGREES! PREPARE FOR TWO DEGREES OF DOOM BY 2100!! But to warm two degrees by 2100, you have to warm at 0.2°C per decade, or around 0.4°C during “the pause” … so they are now left trying to explain a missing warming that’s two-thirds of the 20th century warming of 0.6°C. One hates to confess to schadenfreude, but I’m sworn to honesty in these pages …
In any case, I got to thinking about their explanation that it wuz the volcanoes what done it, guv’nor, honest it wuz, and I did something I’d never thought to do. I calculated how much actual loss of solar energy occurs when there is a volcanic eruption. I did this by using the Mauna Loa atmospheric transmission data. These observations record what percentage of the solar energy is being absorbed by the atmosphere above the observatory. I multiplied this absorption percentage by the 24/7 average amount of solar energy (after albedo) which strikes Mauna Loa, which turns out to be 287 W/m2. (As you’d expect from their tropical location, this is larger than the global average of 240 W/m2 of sunlight after albedo). Figure 1 shows that result, which was a surprise to me:
Figure 1. Amount of solar energy absorbed by the atmosphere above Mauna Loa, Hawaii. Data Source
Now, before I discuss the surprising aspects of this graph, let me note that the Mauna Loa data very sensitively measures the effect of volcanic eruptions. Even small volcanoes show up in the record, and the big volcanoes are clearly visible. Given that … is there anyone out there foolish enough to buy the Susan Solomon explanation that the cause of the pause can be found in the volcanoes? I guess there must be people like that, the claim has been uncritically accepted in far too many circles, but really … who ya gonna trust? Susan Solomon, or your own lying eyes?
I’ll return to the question of the pause, but first let me talk of surprises. The thing that was surprising to me in this was the size of the loss of solar energy. The El Chichón and Pinatubo eruptions reduced the downwelling solar energy by maxima of forty and thirty watts per square metre at Mauna Loa. This is a huge reduction, much more than I would have guessed.
One measure of how much energy is lost is the total loss until such time as the absorption returns to its pre-eruption value. It turns out that in the case of both El Chichon and Pinatubo, the net loss of solar energy was about 450 watt-months per square metre. The loss was spread more widely (5 years) in the case of El Chichon than in the case of Pinatubo (3 years) before it returned to normal.
This means that for the period 1982-1987, Mauna Loa was running at 450 W-months/m2 divided by 60 months equals an average deficit of no less than 7.5 W/m2 of incoming energy over the five-year period … and it’s worse for Pinatubo, since that involved the same total energy but only lasted for three years. So for the three years from 1991-1994, Mauna Loa was running at a whacking great average solar energy deficit of 14 W/m2 …
Now, how much difference did this surprisingly large lack of incoming energy make? According to the IPCC, climate sensitivity is 3° per doubling of CO2, and a doubling of CO2 is a forcing increase of 3.7 W/m2 … and Mauna Loa was running at 14W/m2 shy of normal, that’s almost four doublings of CO2. So according to the IPCC, that kind of a decrease in forcing should have lead to a temperature drop of 11°C … so what actually happened?
Well, we’re in fantastic luck, because the temperature records at Mauna Loa are very good. Here’s what they say (study here):
Figure 2. Mauna Loa temperatures. Vertical red lines show the dates of the El Chichon (March 1982) and Pinatubo (June 1991) Graph from B. D. Malamud et al.: Temperature trends at the Mauna Loa observatory, Hawaii.
As you can see, despite the large decrease in incoming sunshine, there is absolutely no visible change in either the noon or the midnight temperatures … go figure. What happened from the volcano is nothing at all. No effect.
Now, y’all may recall that I have argued over and over against the concept of climate sensitivity. This is the widely-accepted hypothesis that the changes in temperature are determined by the changes in forcing. I’m a climate heretic—I don’t think climate works that way at all.
In particular, despite widespread skepticism, I have persisted in saying that volcanoes basically don’t do jack in the way of affecting the global temperature. I can finally demonstrate that unequivocally because I’ve stumbled across a very well-documented and precisely measured natural experiment.
At Mauna Loa we have a clear example of a measured decrease of 7 W/m2 in the average incoming solar energy for five years (1982-1987), and a decrease of 14 W/m2 for 3 years (1991-1994) … and there is absolutely no sign of either forcing decrease in the temperature record of the very place where the solar decrease was measured.
As I’ve said over and over, the emergent phenomena of the climate system respond instantly (hours or days, not months or years) to any change in the temperature. If it cools, we rapidly get a drop in albedo, which allows in more sun, and the balance is restored. If it warms, very soon thereafter albedo increases, we get less sun, and again the balance is restored. So while I was surprised by the size of the drop in downwelling solar energy, I was not surprised that we can’t find the signal of the solar drop in the temperature records.
Setting that question aside, let me return to the “pause”. Solomon et al. used the Vernier aerosol optical depth (AOD) dataset, which is available here. It is a calculated global dataset based on various observations. The explanation of the calculations is here. If anything, there is less recent variation in that dataset than in the Mauna Loa dataset. Figure 3 compares the two over the period of the satellite temperature observations.
Figure 3. Compares the negative of the aerosol optical depth with the Mauna Loa transmissivity data. Mauna Loa data rescaled to match AOD data for comparison purposes only.
So it doesn’t much matter which one we use to compare to the temperature data. Let me use the Mauna Loa transmissivity data, since the native units are in the same range as the temperature anomaly. Figure 4 shows the comparison of the Mauna Loa transmission data with the UAH MSU satellite-based lower troposphere temperature data:
Figure 4. Satellite lower tropospheric temperatures (blue) and Mauna Loa solar transmission (black line). Note that while Pinatubo happened at the start of a temperature drop, El Chichon happened at the start of a temperature rise. In addition, in neither case are the rise or the drop notable—the drop 1988-1989 or 2007-2009 is indistinguishable from the post-Pinatubo drop.
Finally, lest some folks claim that because Mauna Loa is in the northern hemisphere we can’t compare it to the global temperature changes, Figure 5 shows the comparison of the Mauna Loa with the northern hemisphere temperatures:
Like I said … I know there must be folks out there that can be convinced that the changes in the black line, the known effects of the volcanoes, are the reason that there is a “pause” in the global temperatures … I’m not one of them.
CONCLUSIONS:
• I may never find better evidence of the lack of connection between changes in forcing and changes in temperature than the measured large drop in solar forcing and the total lack of corresponding temperature change at Mauna Loa. It is a superb natural experiment, and has been very precisely measured for over half a century. It provides strong evidence in favor of my hypothesis that the temperature is controlled by emergent phenomena, and has very little to do with forcing.
• The change in forcing from the 21st century volcanoes is trivially small in both the Vernier AOD dataset and the Mauna Loa dataset. It is far too small to have the effect that they are claiming. I don’t care what the climate models told Solomon et al., the post-2000 changes in volcanic forcing are meaningless.
• My oft-repeated claims about the lack of effect of volcanoes on the global temperature are completely borne out by these results.
My regards to all,
w.
AS ALWAYS: If you disagree with me or anyone, please quote the words you disagree with. That way we can all know exactly what it is you have a problem with. Vague handwaving claims go nowhere.
MAUNA LOA TRANSMISSION DATA: From their website
The “apparent” transmission, or transmission ratio (Ellis & Pueschel, Science, 1971), is derived from broadband (0.3 to 2.8um) direct solar irradiance observations at the Mauna Loa Observatory (19.533 ° N, 155.578 ° W, elev. 3.4 km) in Hawaii. Data are for clear-sky mornings between solar elevations of 11.3 and 30 degrees.
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I do hope someone is compiling the excuse list. I’ve lost track of all the random factor list and hiding places for heat.
thingadonta beat me to it. “The volcanoes ate my warming.” Except the volcanoes are invisible, and have no measurable effect on the transmission of sunlight. Are these climate scientists at Faber College? They must be Dean Wormer’s double-secret volcanoes. (RIP, Harold Ramis). Their only measurable property is the ability to excuse the absence of warming. How does this stuff get past peer review?
Willis, did you see this?
http://notrickszone.com/2013/12/22/disappearing-excuses-aerosols-likely-not-behind-the-warming-pause/
That’s been pretty clear since the mid-1950s.
Stephen Richards says:
February 25, 2014 at 1:43 am
How does an ice age form ? Milankovic possible but there are many if and buts around the predicted incoming energy change. So what else is there.?
Albedo. When the solar input tilts a little more towards the SH (Milankovitch cycle) the sea ice around Antarctica becomes a larger source of albedo. As we’ve seen recently this sea ice can increase quite dramatically, most likely due to deep ocean currents. This starts to cool the Earth. This overall cooling allows more snow in the NH to last longer into the spring and summer creating even more albedo. The two forces positively enforce each other until the NH snow is maintained all summer long and the glaciers start to form.
Willis, you’ve said repeatedly, “the emergent phenomena of the climate system respond instantly (hours or days, not months or years) to any change in the temperature. If it cools, we rapidly get a drop in albedo, which allows in more sun, and the balance is restored. If it warms, very soon thereafter albedo increases, we get less sun, and again the balance is restored.”
I agree there appear to be significant negative feedback systems working to prevent runaway effects. However, this seems to imply that we would never get a significant temperature change. However, we know that there have been well-documented warmer and cooler periods even just since the little ice age.
How do you account for these changes given the negative feedbacks?
kb
On the one hand, (1st order, linear) correlation is not causality. On the other hand, lack of correlation makes causality even less likely — to continue to argue for causality one has to postulate a far more complex, multivariate system rather than a simple linear response hypothesis. And the trouble with that sort of hypothesis — which I firmly endorse — is that it shuts down all the simple, trivial, bullshit arguments — deconstructing a complex, nonlinear, strongly coupled dynamical system on the basis of some combination of model(s) and observation is not a job for the faint of heart, and it is one where one can only gain insight after understanding at least the principle non-linear features of the system dynamics.
are rate parameters, related to probabilities of encounter. One can look at:
from any given initial condition and set of parameters. The numbers of foxes and rabbits form a cycle — for almost all possible numbers of foxes and rabbits the population is disequilibrated relative to a fixed point where “equilibrium” occurs. Rabbits increase. Eventually foxes respond to this increase, and increase as well. As there are more and more foxes and rabbits, eventually well-fed, rapidly reproducing foxes overtake the rabbits and the rabbit population starts to decrease. Eventually one has a large population of foxes all slowly starving, a small number of rabbits that are finally rare enough that they can hide from the foxes, and the foxes die off to where the small rabbit population can once again start to soar in a nearly fox-free environment.
and 
are constants in time — they are fixed and the model evolves deterministically and if it is indeed linear, often computably.
where there can be both systematic variation (think of the way TSI varies due to the simple shape of planetary orbit) and stochastic variation (where we cannot predict the microstate of the sun from hour to hour or day to day and in any event it follows no “nice” curve — it is at best modelled by a random process with certain properties even though it is hardly random). Think albedo — changing from hour to hour, but in a generally bounded way, but where it is not clear if albedo is stationary on a decadal timescale, if it depends in critical ways on things like solar state or aerosol content or soot content of the atmosphere, all of which themselves are varying.
or the other parameters, makes the attractor jump farther away from the existing population values. If you simply add a certain amount of dynamic stochastic noise to the parameters, basically “shake up” the attractor so it does a random walk (constrained or unconstrained) since there are no dissipative terms in the coupled ODEs that cause the system to stabilize and relax to a bounded orbital range, it is quite likely that the system will get “shaken” into less and less stable orbits, increasing the probability of catastrophe.
One of my favorite examples from my unholy past is solving predator-prey (Lotka-Volterra) or epidemiological equations. These are systems of coupled differential equations that describe in the crudest of terms population dynamics of two coupled populations, one of prey (say, rabbits) and the other of a predator (say, foxes) that relies strictly on the rabbits as a food source. In the simples forms, the rabbits are presumed to live in a more or less unboundedly good environment and have no other source of demise. Rabbits breed more rabbits at a rate proportional to the number of rabbits, which in the absence of foxes would lead to an exponential explosion in the number of rabbits. However, foxes eat rabbits at a rate proportional to the probability of a meeting (yes, every time a fox and rabbit meet the fox eats a rabbit, it’s an oversimplified model) which decreases the number of rabbits.
Foxes, on the other hand, die off in the absence of rabbits. They do reproduce at a rate proportional to the number of foxes times the number of rabbits, but if the number of rabbits gets too small foxes starve to death faster than they reproduce no matter how many foxes there are. Put these together, and one gets a very simple linear model:
The constants
http://en.wikipedia.org/wiki/Lotka%E2%80%93Volterra_equation
if this sort of thing interests you. In particular look at the complexity of the solutions
The stable points of the cycles are called attractors, and there is an entire literature dedicated to attractors, strange attractors, and limit cycles that can be periodic/poincare or chaotic. This simple model gets very complex indeed with tiny changes — making the interactions nonlinear, introducing a second predator or second prey animal, adding terms to represent plant life and the possibility of rabbits consuming all of their food source with or without fox predation, adding diseases that kill off rabbits very rapidly from epidemics once the rabbit population crosses critical thresholds where the probability of transmission of e.g. Tularaemia crosses a critical threshold where every infected rabbit infects on average more than one other rabbit. I’ve actually written discretized Monte Carlo code to simulate epidemiological models (for venereal disease) for fun for my wife and a fairly well known epidemiologist back when she was an infectious disease fellow, and was told that the results of the computations had some influence on their thinking (although I don’t know that I got as much as an acknowledgement in a paper, sigh).
Now imagine trying to model an entire ecology. Or (since similar models are used in economics) the market. Or yeah, the climate.
The problem is this. In a linear model, one can do things like solve for the stable points — the attractors — in some high-dimensional space, and one can even talk sensibly about limit cycles or at the very least comparatively bounded cyclic behavior of the system as it traverses curves in phase space bound to attractors. That’s because terms like
In a nonlinear model, all bets are off. In a model that is both nonlinear and has non-stationary values of the coupling constants, the moral equivalent of
In this case the attractors themselves in any semi-linearized dynamical model are wandering all over the place. In a truly nonlinear model, the system often has multiple (strange) attractors, attractors in fractal distributions, and they are constantly moving, causing the entire topology of the quasi-cyclic evolution to change on the same time scale as the motion itself.
As Willis says, the really amazing thing is that the climate is remarkably stable in the short run to perturbations, stubbornly staying locked within a comparatively small temperature range where planetary life is abundant. Except, of course, when it doesn’t and we plunge into glacial eras lasting 90,000 years where ice kilometers thick builds up on close to 1/4 of the Earth’s surface near the poles and up high in the mountains.
It is partly because this sort of instability — or global multistability, with entirely distinct characters of strange attractor families appearing in the empirical record — that I think it is, on the whole, wiser not to kick the climate in the balls when we have no idea where it will end up. Increasing CO_2 in a strongly coupled nonlinear system could just as easily trigger the next ice age as cause thermageddon from heat.
You don’t believe me? Take a gander at the predator prey problem. When the numbers stay near the attractor, life is good for foxes and rabbits. Few rabbits starve, few foxes starve, fox/rabbit numbers stay close to some sort of “optimal” number for the presumed problem ecology. Bump either the number of foxes or the number of rabbits and all you do is kick the system into a large limit cycle, one that in time will carry both foxes and rabbits closer to extinction. Exactly the same thing will happen if one “suddenly bumps” e.g.
We could all argue about how likely this sort of catastrophe is for the real climate, but the fact of the matter is that we have no idea, and our models don’t come close to being able to explain the observed climate variability. If you like, the cyclic structure, stability, fluctuation/dissipation, time constants, attractor(s) of the GCMs do not exist in good correspondence with the actual climate. We don’t really know what the climate would be doing without a systematic hand twisting up the CO_2 knob (and doing crazy, mad things with all of the other knobs in the system even as the system is thrashing its enormous way through multiple interacting decadal cycles around attractors we are completely incapable of describing or incorporating consistently into a dynamic model). It could, paradoxically enough, be stabilizing the system — pulling it tighter to the family of currently stable strange attractors, reducing the excursion of the attractors. It could be squeezing the system — altering the geometry of the cyclic motion, constraining the attractor excursions to a changing/flattening hyperellipsoidal volume. What it probably isn’t doing is nothing, and what we can’t do is predict how the system will respond on a decadal time scale, any more than we can for foxes and rabbits as an approximation for an actual ecology.
All things being equal, the human species needs to gradually wean itself from carbon-based fossil fuels, both because CO_2 has a mostly unknown (but almost certainly nonzero) effect on the climate that could be good, could be bad, could be first good and then bad, could be almost anything, and because fossil fuels are a precious resource far more valuable as the basis of chemistry or smelting or making concrete than they are for burning. We are burning a long term planetary resource at a prodigious rate. Ultimately, human civilization will need to be based on energy resources that are substantially less limited by scarcity, resources that might last through the next glacial era in the current ice age, or humans will experience their own “mass extinction event”.
In the meantime, because we really do not know what the climate is doing or will do in the future, but we have the immediate need to keep people from starving or living in energy poverty, the sensible thing to do is wait, watch, burn carbon as needed but invest fairly heavily in non-carbon-based energy for the long term. Fission (Uranium and Thorium), solar (sorry, I know a lot of you think solar is some sort of devil but I just think it is a devil that is already making borderline economic sense to the point where I’m contemplating putting solar on my own roof and am doing a ROI analysis to see what the amortized payback time is) and ultimately, we can profoundly hope, fusion as if we ever perfect D-D fusion the human species will make the transition to stability — we will never run out of energy in less than geological time (millions of years, if then). The human species will evolve or go extinct long before we even measurably reduce the amount of deuterium in the oceans.
rgb
I’m also wonder, how much do the aerosols above clouds diminish the cooling effect of clouds? Is it significant enough that cloulds could become net warming and the increased cloud cover help prevent cooling instead of cause it?
The problem with Dr Solomon’s theory is that we haven’t had any erruptions during the last 15 years that have come close to Mt Pinatubo or El Chicon.
Bill Illis says:
February 25, 2014 at 3:40 am
If a large stratospheric eruption has no temperature impact …
How can no volcanoes have a large temperature impact?
In climate science, this actually makes sense to them.
This reminds me of the old Jean Paul Sartre joke.
The existentialist sits in a Paris Cafe, and orders…”Madame, I would like coffee with no cream”
The waitress comes back, monsieur Sartre, we are out of cream, would coffee without milk be acceptable to you?
RGBatDuke,
Your expertise and eloquence are undeniable. However, your conclusion (or hypothesis) based on analogy that, “What it [CO2] probably isn’t doing is nothing…” is without merit based on your argument (if “probably” means better than 50/ 50 odds, and “nothing” means in relevance to CAGW). The issue of CO2-driven CAGW is one of physics, not of what, generic, non-linear choatic, multi-process systems do or might do. And, as for the physics effects of CO2 on global temps/ climate, well, as you indicate, we have no idea. However, given the amazing stability of the temp/ climate system would it not seem unlikely to be knocked out of that stability by anything but rather large changes in energy input, such as implied by Milankovitch cycles?
Is it not likely the huge H2O heat sink we have, the physics of the hydrological cycle, along with the inherent dynamics of a gaseous envelope overwhelm almost everything except those rather large changes in energy input?
I also question your point about limited coal/ oil/ gas resources. Assuming markets are allowed to work such that price reflects scarcity, the odds are high, based on the geology of exploitation, that scarcity will not emerge suddenly in the course of a few decades, but rather gradually such that price will cause alternative energy sources to be brought into the market to replace increasingly-expensive fossil fuels. (Big assumption here: that governments are not uniformly intransigent to economic reality…. they can be sometimes, of course, but usually only for a few decades; e.g., Soviet Union and China).
Finally, are you taking into account the huge subsidies that factor into your cost of solar panels? While I can understand you taking advantage of those subsidies for purely personal economic reasons, I cannot abide that example as part of an argument for solar becoming economic. In addition, and sadly, energy prices are probably higher today than they might be if the US government were CO2-neutral on what sources of energy could be exploited.
I appreciate your incisive arguments that debunk simplistic climate science, but I wonder if you haven’t done a little too much hand-waving in this latest piece.
Does the paper actually claim the volcanoes did it? The press reports I’ve seen all seem to say only that ‘volcanoes cause cooling.’ There is no detail where they actually argue that there is more volcanoes now than before. It would be like if I said StefanBoltzman says warmer objects emit more heat into space, and argued that that is the reason for the pause.
Ok, think of this dynamic. Less SW reaches the clouds, however, the SW that does is more likely to be absorbed because it is reflected back down by the aerosol in both the SW, and LW by the stratospheric GHE Dr. Spencer mentioned. So there’s less heat at the near surface and more between the cloud layer and stratospheric greenhouse (do satellites see higher surface temps than surface stations?).
Now, all over the world, there’s less SW reaching bodies of water and moist surfaces. I’d like to know more about the water vapor feedback research in the IPCC report and models. I recall much of it was considered confirmed by volcano effect analysis. I bet they account for temperature, maybe wind, but not the direct effect of SW radiation.
Willis, like Bob Tisdale has pointed out to you on many occasions, the global temperature rise in 1982/83 is clearly caused by the massive El Niño that year. Yet, there’s a very stunted global response. And the significant global temperature drop between 1992 and 1995 came during a period of mostly positive to distinctly positive ENSO-conditions. It goes the opposite way of what one could expect.
It is very clear from this that both the El Chichón and (especially) the Pinatubo eruptions had a major impact on global temperatures. Of course, they would not have a major impact (or not necessarily a noticable impact at all) on regional or local temperatures (like Mauna Loa). Because here, normal variations are too large and … regional/local. The volcanic influence is small compared to for instance cloud cover and year-to-year variations in regional/local weather because of position of pressure systems, winds, rains and so forth, but it is an influence that works globally. So the further you zoom out, the clearer the volcanic signal will stand out.
rgbatduke: “Put these together, and one gets a very simple linear model:”
A nomenclature question, if I may, regarding the term “linear.” I had thought I understood from people who seemed to know this stuff that equations such as those you set forth above are considered nonlinear, i.e., that, because of the RF term, the fact that [R_1(t), F_1(t)] and [R_2(t), F_2(t)] individually are solutions would not necessarily imply that [R_1(t), F_1(t)] + [R_2(t), F_2(t)] is.
Could I impose upon you to explain the meaning of “linear” in this context and what the implications of that feature are?
LB, it depends on distribution of the effect. There should be bigger temp drops in mid to low latitudes, decreasing temp and pressure differentials with the north.
Agnostic says:
February 25, 2014 at 12:36 am
The reduction in incoming sunlight from e.g. El Chichon was global in nature. The signs of it were picked up all over the world. So we can assume that over the entire Pacific there was a very large drop in incoming sunlight, not just at Mauna Loa. As a result, we should have seen widespread cooling, including at Mauna Loa … but we saw none, either at Mauna Loa or in the UAH MSU satellite records for the northern hemisphere lower tropical temperatures.
They are both measured at MLO, the Mauna Loa Observatory. That’s one reason that it’s such a good natural experiment.
Actually, what I said above was that the lack of temperature response was not surprising, at least not to me. The major compensatory mechanism of the planet, the thunderstorms, are fast-acting and very powerful. They, and the other emergent phenomena, only emerge based on the actual present conditions. So when the temperature rises between dawn and noon, as soon as the threshold is passed the cumulus appears. And as a result, there is little lag in the response.
w.
Michael Larkin says:
February 25, 2014 at 12:59 am
Michael, good question. The key is that in general the atmosphere absorbs about 20 W/m2 of solar energy at MLO. So the eruptions reduced the energy by 40 and 30 W/m2 … when you include the twenty W/m2 you get your figures of 60 and 50, but that’s the total absorption, not the reduction caused by the volcanoes.
w.
Well done (as usual) Willis. You’ve quantified what I’ve been saying qualitatively for decades–(1) volcanic eruptions are too short-lived to affect climate over long periods of times, (2) volcanic eruptions are sporadic, not cyclical like climate, (3) there is no known correlation between volcanic activity and climate over long periods of time, and (4) a volcanic cause of global warming is thus not plausible.
Now it WOULD be interesting to see data from the African deserts over time. Since it is always “blowing in the wind” and African periods of rain and periods of drought correspond to weather pattern variations, I surmise that sometimes there is a lot and sometimes there is less of this dust. At the very least, this dust is ubiquitously present to one degree or another in a very important part of the globe.
johnmarshall says:
February 25, 2014 at 2:45 am
Egads, sire, such passion! “Get Real” indeed … let’s do just that. Here’s the reality.
We start with the TOA solar irradiation, which is about 1360 W/m2. It is intercepted by the disk of the earth, with a cross-sectional area intercepting the sunlight of pi * r2 square metres, where r is the earth’s radius. So the total energy intercepted by the earth is 1360 pi r2 watts. Note that the square metres cancelled, so this is the total insolation in watts.
Now, how much does that average out to per square metre of planetary surface area? To get that, we divide the total intercepted energy in watts (1360 pi r2) by the total surface area in square metres, to give us watts per square metre. The surface area of the planet is 4 pi r2. As you can see, this calculation gives us
1360 pi r2 / 4 pi r2 = 1360/4 ≈ 340 W/m2 average solar radiation.
Now, as you point out, about 100 W/m2 of the incoming solar energy is reflected back to space, leaving us with the 240 W/m2 as the figure I used for the average insolation after albedo.
Finally, you are correct that the SB formula gives ~ -18°C as the blackbody equivalent of the radiation of 240 W/m2 … and since the planet is not frozen, we note that the poorly-named “greenhouse effect” is alive and well, and keeping us from freezing.
w.
Watts Up With Your Maffs says:
February 25, 2014 at 3:28 am
Well, um, no. You don’t just take the starting and ending temperature to determine the trend. You need to actually calculate the trend. Grab a “maffs” textbook, the maths aren’t too hard, or get Excel to do the heavy lifting for you.
For the 20-year period from Jan 1994 to Dec 2013, the GISS LOTI trend was 0.09°C per decade. This is so small that it is not statistically significant (p = 0.09). In addition, it covers a deeper reality, which is that the trend for the entire 21st century to date is 0.02°C per decade. So my point stands. By now, given the DEATH BY TWO DEGREES WARMING BY 2100 claims, we should have seen a lot of warming.
We haven’t, and that’s what Solomon et al. are scrambling to explain.
w.
PS—Please take this in the right way, but your screen name is pathetic. It makes you look like an illiterate loser wannabe. I’d change it if I were you … just saying, if you want to get traction, the name’s not helping.
Willis says:
“• My oft-repeated claims about the lack of effect of volcanoes on the global temperature are completely borne out by these results.”
When land based volcanic activity occurs on the 30% of the Earth’s surface which is not covered by oceans, one could hypothisize that undersea eruptions are adding heat to the oceans at the same time in that 70% of the planet for which data is limited to non-existent. Too bad our data on these eruptions is so limited. The late Iben Browning believed that volcanism worldwide was cyclical and inter-related. If so, then, at times, when we see high land based activity there may be even more undersea activity in that 70% that we do not see, thereby increasing temperature on a global basis by warming the oceans. In any event, that undersea volcanic activity is a variable to be considered along with the time lag for that heat to reach the surface and/or effect the oceanic oscillations. Perhaps as part of your theorized planetary self regulation or one of the causal variables which now and again significantly disrupt that regualtion.
rgbatduke, a very enjoyable post about something I know just a little from a course I took many years ago. There are three conclusions that you came to that I don’t agree with. The first conclusion is really more of an implication from what you wrote – essentially that we can control our CO2 output. This is essentially false at our current technological and social development level. Population is growing fast and the desire to live prosperous lives is not changing. Therefore, more energy is needed and will be used. Hydrocarbons and coal will be burned until a less expensive alternative is developed. You wrote that we would need the hydrocarbons in the future. There will always be hydrocarbons available. The issue is expense. Most hydrocarbons are locked in shale or rock that is very impermeable. Better technology, more oil and gas we get from those rocks (example the shale boom in North America). The race is not to stop using hydrocarbons, the race is to advance our technology such that we become more efficient and develop other inexpensive energy alternatives to hydrocarbons. If we don’t, civilization will gradually crash as we run out of inexpensive energy- with the hydrocarbon and coal mining extraction continuing apace.
Your idea that CO2 is likely to cause some change is likely true. However, your conclusions are not. CO2 has varied in the geological past with periods of time where CO2 was much higher than now and periods when it is not. Yet life flourished on the earth during those periods of time. The earth temperatures were very stable during those periods except during periods of time when the earth experienced ice ages. But even in ice ages, the ice stopped advancing at some point and the earth reached another fairly stable period. Given, we know that temperature and conditions remain very stable even though there are events that occur such as volcanoes and even super volcanoes and other calamities that in the geological record are very brief as temperatures and conditions return to a stable value very quickly. From the geological record, it seems very unlikely that changes in CO2 are capable of having a huge impact on temperature. This implies robust negative feedback mechanisms that bring the earth back to a relative equilibrium. Finally, geology and and life over the last 500 million years, has gradually sequestered more and more CO2 into sediment. This has caused the gradual decline of CO2 in our atmosphere. The decline is forcing evolutionary changes in life such as the development of plants that are able to concentrate CO2. Most food plants are such but most plants on earth are not. Eventually, if trends continue, CO2 levels will get low enough that most current life will become extinct and something else takes over while life can flourish on planet earth. Our stay on earth will increase the levels of CO2 “dramatically” for only a brief time geologically speaking – but from the point of view of current life on earth that flourishes in the present of CO2, this increase is a very good thing.
Roy Spencer says:
February 25, 2014 at 3:58 am
Dr. Roy, do you have a source for that statement? I ask because the only record that I have of albedo around the time of Pinatubo, the Hatzianastassiou dataset, looks like this:
As you can see, hemispheric albedo dropped immediately following the eruption. I ascribe this, of course, to the delayed daily formation of cumulus and cumulonimbus when there are reduced tropical temperatures …
I’ve always ascribed the majority of that stratospheric warming to the increased absorption of sunlight. Even the brightest and most reflective of aerosols absorb some sunlight, and the dark aerosols, particularly black carbon, absorb a majority of the incident sunlight.
It’s an interesting question, however, and one which I haven’t considered, as to which would warm it more, SW or LW absorption.
All the best to you, and as always, thanks for all the good word you’ve done. As you can see in the figures, I use the fruits of your labors in my research all the time.
w.