Guest Post by Willis Eschenbach [also, see update at the end of the post]
Anthony recently highlighted a couple of new papers claiming to explain the current plateau in global warming. This time, it’s volcanoes, but the claim this time is that it’s not the big volcanoes. It’s the small volcanoes. The studies both seem to follow what I call “Willis’s Rule of Author Count”. The first study is Total volcanic stratospheric aerosol optical depths and implications for global climate change, by D. A. Ridley, S. Solomon, J. E. Barnes, V. D. Burlakov, T. Deshler, S. I. Dolgii, A. B. Herber, T. Nagai, R. R. Neely III, A. V. Nevzorov, C. Ritter, T. Sakai, B. D. Santer, M. Sato, A. Schmidt, O. Uchino andJ. P. Vernier. The second study is Observed multi-variable signals of late 20th and early 21st century volcanic activity, by Benjamin D. Santer, Susan Solomon, Céline Bonfils, Mark D. Zelinka, Jeffrey F. Painter, Francisco Beltran, John C. Fyfe, Gardar Johannesson, Carl Mears, David A. Ridley, Jean-Paul Vernier, Frank J. Wentz.
Now, Willis’s Rule of Author Count says that the quality of any study is inversely proportional to the square of the number of listed authors. And these two studies have seventeen and twelve authors respectively … not a good sign.
The abstract of the first paper says:
Understanding the cooling effect of recent volcanoes is of particular interest in the context of the post-2000 slowing of the rate of global warming. Satellite observations of aerosol optical depth above 15 km have demonstrated that small-magnitude volcanic eruptions substantially perturb incoming solar radiation. Here we use lidar, Aerosol Robotic Network, and balloon-borne observations to provide evidence that currently available satellite databases neglect substantial amounts of volcanic aerosol between the tropopause and 15 km at middle to high latitudes and therefore underestimate total radiative forcing resulting from the recent eruptions.
The abstract of the second paper, in turn, says:
The relatively muted warming of the surface and lower troposphere since 1998 has attracted considerable attention. One contributory factor to this “warming hiatus” is an increase in volcanically-induced cooling over the early 21st century. Here, we identify the signals of late 20th and early 21st century volcanic activity in multiple observed climate variables. Volcanic signals are statistically discernible in spatial averages of tropical and near-global SST, tropospheric temperature, net clear-sky short-wave radiation, and atmospheric water vapor.
Now, it is certainly possible that “small-magnitude volcanic eruptions substantially perturb incoming solar radiation”. There are lots of things that perturb incoming solar radiation, with clouds heading the list. Whether small volcano emissions in turn perturb the global surface temperature is a separate question.
But for eruptions to be an explanation for the current plateau in global warming, the authors would have to show a significant increase in volcanic eruptions in the 21st century. And unfortunately (but predictably) I see no sign in either paper that they have even tried to do that.
So let’s do their job for them by taking a look at the actual records of eruptions, both large and small. The data on all known eruptions is available from the Smithsonian Volcanism Project.
Now, we have some choices in how to display this data. Let me show three of these different ways.
First, we can show the total numbers of eruptions by year, without regard to the size of the eruption. Figure 1 shows that information:
Figure 1. Count of all volcanic eruptions, regardless of their strength, during the end of the 20th and the start of the 21st centuries.
As you can see, there is very little difference between the post-2000 (or post 1998, depending on the study) eruption count and the number of eruptions during the end of the 20th century. After 2000 (or 1998), it went up a bit, then it went down a bit … overall, little change.
But wait, I can hear you saying, the eruptions are not all of the same strength … what is the average strength of the eruptions? And reasonably so, since strong eruptions would have a bigger effect than small eruptions. So let’s look at that data.
The strength of an eruption is measured by the volcanic explosivity index, or VEI. This is a logarithmic scale. This means that an eruption with a VEI of 5 is ten times stronger than an eruption with a VEI of 4, and so on.
In order to properly average these, it’s necessary to use a “logarithmic mean” To do this, you first convert the VEIs to actual values (by taking ten to the power of the VEI). Then you average the actual values, and then take the logarithm of the resulting average to convert it back into the logarithmic VEI scale. Figure 2 shows that result:
Figure 2. Annual logarithmic mean of the volcanic explosivity index, all volcanoes.
In 1991, there were two strong eruptions, Pinatubo (VEI of 6) and Cerro Hudson (VEI of 5). Other than that, there’s not a lot of variation.
Once again, you can see that the post 2000 (or post 1998) average strength of the volcanic eruptions are little different from the strength of the eruptions prior to the turn of the century. So that cannot be the cause of 21st century plateau in global surface temperatures.
Finally, we could read the implicit claim as being that there is some kind of increase in the number of small volcanic eruptions. After all, the authors say that these are the overlooked eruptions. So let’s take a look at the small pre- and post-2000 eruptions.
Figure 3. Annual count of the smaller eruptions, those with a volcanic explosivity index of less than 3.
Once again, we see little change in the number of small volcanoes. After 2000, it goes above the average, and then it goes about the same amount below the average.
Conclusions? Well, the papers may be correct in their claim that the effect of eruptions on the clarity of the atmosphere may have been underestimated.
But they are absolutely not correct in the claim that this underestimation reveals the cause of the recent 18+ year plateau in temperatures as being eruptions. There is almost no post-2000 change in either the number of eruptions, the strength of eruptions, or the number of small eruptions.
Overall? I’d say that Willis’s Rule of Author Count, that the quality of any study goes down inversely proportional to the square of the number of listed authors, is validated once again …
[UPDATE: The underlying claim of these two papers is that although there have been no large eruptions in the 21st century, it is the weaker eruptions that are causing the plateau in temperature. These are eruptions with a volcanic explosivity index (VEI) of four. Some commenters below still think that the eruptions of VEI four are significant. The Santer document shows the effect of some of the VEI 4 eruptions on the stratospheric aerosol optical depth (SAOD), which is their main indication of volcanic change. The study says:
We use stratospheric aerosol optical depth (SAOD) data from Vernier et al. [2011] to study changes in stratospheric loadings of volcanic aerosol.
The eruptions make a change of about .002 in the SAOD, viz:
Now, that looks kind of impressive … until you compare it to the larger volcanoes (source):
You can see the sizes of Krakatoa in the 1880s, Pinatubo in 1991, El Chichon in 1982, and Mt. Agung in 1963, along with some smaller volcanoes … and then you can see the part that Santer et al. are discussing. This is the almost-flat line in the post-2000 era. Sorry, but given the short-term, weak, local effects of even the largest volcanoes, I’m not buying the idea that those tiny post-2000 wiggles have any discernible effect at all.
My best regards to you all,
w.
ONCE AGAIN: If you disagree with someone, please do everyone the favor of QUOTING THE EXACT WORDS THAT YOU DISAGREE WITH. This prevents all kinds of misunderstandings and misrepresentations.
FURTHER READING: I note that this is not the first time that Susan Solomon has made the claim that volcanoes are the cause of the current pause in temperatures. In addition, she was the main mover behind one of the IPCC reports, from memory the Fourth, and is fully and completely invested in the meme of “CO2 Roolz Everything, OK” … whenever I see her name on a study, I’m sad to report that I just wince. See here for my discussion of her previous work.
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Even in 105 F Phoenix you have to heat your pool from within to compensate for the heat lost to evaporation. Same with the oceans, the heat comes from inside, not from the LWIR/CO2 heated air. It’s water vapor, the most powerful GHG, precipitation, clouds, albedo, winds that power the climate. CO2 is a bee fart in that hurricane.
IPCC AR5 TS.6 Key Uncertainties is where climate science “experts” admit what they don’t know about some really important stuff. They are uncertain about the connection between climate change and extreme weather especially drought. Like the 3” drought that hit Phoenix. They are uncertain about how the ice caps and sheets behave. Instead of gone missing they are bigger than ever. They are uncertain about heating in the ocean below 2,000 meters which is 50% of it, but they “wag” that’s where the missing heat of the AGW hiatus went, maybe. They are uncertain about the magnitude of the CO2 feedback loop, which is not surprising since after 17 plus years of rising CO2 and no rising temperatures it’s pretty clear whatever the magnitude, CO2 makes no difference.
http://www.writerbeat.com/articles/3713-CO2-Feedback-Loop
Barring some serious flaw in science or method, Miatello’s paper should serve as the death certificate for AGW/CCC.
http://principia-scientific.org/publications/PSI_Miatello_Refutation_GHE.pdf
http://www.climatism.net/facts-about-global-warming/http://www.seipub.org/des/paperInfo.aspx?ID=21810
The summary states:
“In our view the greenhouse phenomenon, as it was postulated by J. Fourier (1824), estimated by S. Arrhenius (1906), first quantified by S. Manabe and R. Wetherald (1967), explained by R. Lindzen (2007), and endorsed by the National Academy of Science and the Royal Society (2014), SIMPLY (sic) DOES NOT EXIST” (bold highlighting by others).
Below(LAST PARAGRAPH) from rgtbatduke which is correct to a degree but which assumes the earth dynamic /mean state of the climate is constant which it is not which means the same outcome is not going to come about from a particular forcing at a particular point in time.
I present this argument s
In summary I think climate SENSITIVITY to various forcing is EXPONENTIALLY dependent upon the mean state of the climate/earth dynamics at the time the forcing is taken place which is why correlations are hard to come by and so many different climate outcomes (although a similar trend in a general sense) is always the result.
The climatic outcomes all different over the past 20000 years while the same essential forces have been in play throughout this time frame I think proves my point. This is why no climatic theory no mater how could fails to stand the test of time.
.
I think that both Willis and I are in agreement that the effect of volcanoes of VEI less than 6 is almost completely irrelevant to the climate, and one could argue that even 6’s have a pretty ignorable, highly transient effect on long term trends, with any effect they produce completely disappearing within 1-3 years. That is, volcanoes by definition have no effect whatsoever on the “climate” if we define climate in terms of decadal or longer trends, but they can have an effect on global weather. Obviously this would not be true if e.g. Yellowstone or the Siberian Traps erupted as a supervolcano — a major sulphur-rich eruption that basically never stops on a century time scale — but Pinatubo? Krakatoa? Fooey. I spit on your Krakatoa as having more than a transient effect on the weather, not the climate.
We learn one last thing. The Earth’s climate is awesomely stable
that from rgtduke which is 100% wrong.
Well, sure, depending on the time scale. But still, total temperature variation of maybe 20 C over all inferrable time in the last billion or so years, over a period where the atmospheric chemistry and power output of the sun and radius of the moon’s orbit and configuration of the continents themselves all varied substantially? I call that pretty stable, even when it is currently bi- or multistable with a ~10 C oscillation.
Un stable to current conditions would be a kick into snowball Earth, permanently, or hothouse Earth, equally permanently (that is, on 100 million to billion year timescales — eventually the Sun itself isn’t “stable”).
rgb
Totally agree! Eventually, our star will consume us and the planet will die! Unless humans can travel to another distant planet, we are on a path to extinction, just like all other life on this rock!
http://wattsupwiththat.com/2013/06/02/multiple-intense-abrupt-late-pleisitocene-warming-and-cooling-implications-for-understanding-the-cause-of-global-climate-change/
Here is the historical evidence which refutes the earth ‘s climate is stable.
Salvatore, you’ve shown data which claims that in Greenland the temperature swung by about ± 6°K. Generally this is taken as being around twice the swing of the globe as a whole, since the polar regions swing much more than the tropics. This gives a global swing of about ± 3°K.
Now, the temperature of the planet is about 290K. This means that the “extreme” swing that you’re talking about is a ± 1% swing in the temperature …
To me, far from refuting the idea that the earth’s climate is stable, the fact that the largest temperature swing you can find in a million years is a trivially small ± 1% swing is clear evidence that the earth’s climate is amazingly stable. There is no inherent reason that a system ruled only by clouds and wind should be anywhere near that stable, .
If you had any experience trying to govern an engine to a given speed, you’d recognize that holding even a modern engine with a modern governor to ± 1% is a very difficult task. I fear that you’re talking about things that you don’t really understand. A 1% swing is trivially small, and is evidence of a stable system.
w.
Depends on what you mean by stable, Willis.
The Holocene began with a precipitous rise in temperature of an estimated 4-6° C in a few decades. The whole of the Pleistocene has seen such precipitous temperature excursions either as interstadials or interglacial.
The advance and retreat of continental glaciation, although involving time frames in millennia, is not what I would count as stable. In fact, I view the Pleistocene as a period of climate instability.
I´ve had fun myself showing climate change in kelvins, but to be fair, the baseline for our planet isn´t absolute zero.
The fact is that earth´s climate has ranged between its surface covered with oceans of molten rock & of frozen water ice. If it ever were entirely frozen over during the Cryogenian (Snowball Earth v. Slushball), its average T was probably around -50 C. Its maximum T since the Hadean is unclear, but during the Phanerozoic Eon has rarely exceeded about 25 C.
But during our Eon (past 543 million years), it hasn´t gotten as cold as during the long Cryogenian Period, so climate has indeed been more stable. However even during the Phanerozoic, climate has varied from vast ice sheets at both poles to lush vegetation & crocodilians there.
Hard to compare the stability of earth´s climate with those of its sister planets. Mercury & Venus don´t vary much, due to having almost no atmosphere & too much (although the composition of Mercury´s tenuous atmosphere does vary greatly, but being tidally locked to the sun, its surface ¨climate¨ is reminiscent of our moon´s). Mars was probably more earth-like early in its history, but its climate is fairly stable now, although swept by dust storms & having experienced global warming along with earth (but then so has dwarf planet Pluto). The storm on Jupiter marked by its Great Red Spot has lasted at least hundreds of years.
I think some NASCAR engineers might beg to differ, but then again they are looking for speed over varying track conditions, not necessarily keeping the engine within 1% of any given rpm 🙂
Just say’n.
Speaking of climate on other planets atmospheric carbon, how about diamond rain on the giant planets?:
http://www.bbc.com/news/science-environment-24477667
At least one study suggests peak warmth during the melting of a Snowball Earth interval of 40 degrees C, for a temperature swing of about 90 degrees in the Cryogenian (-50 to +40). Present mean global T is around 14 degrees C.
And yet with this very stable climate the earth has had glacial and inter-glacial periods not just one or twice but many times over. Ice sheets covering vast expanses of the earth at times.
I do not define that as evidence of a stable climate.
My definition of a stable climate would be one in which the mode of the climate would either stay in either a glacial state or inter-glacial state permanently.
The fact that the climate of the earth is so close to a glacial/inter glacial threshold makes a definition of a stable climate in the sense of overall temperature changes for the globe valid but not in the fact that the resultant climate change for much of the globe from glacial versus inter-glacial conditions is drastic.
I guess it is how one wants to define stable.
But RGB was talking of stable temperature.not stable climate. A 1 – 2% variation in temperature over the history of the planet is extraordinarily stable.
Imagine for a moment that you have an ice cube tray of pure water, which you place in a freezer set for 0 degrees C, with a variation of +/- 0.5 degrees. That’s a pretty good thermostat but you’ll find that your ice cubes keep freezing and thawing – very stable temperature but apparently unstable conditions.
The fact that the Earth’s temperature is so stable despite being so close to a point where climate conditions can change quite drastically, and in ways that should have a large effect on one of the known feedbacks, is almost enough to make the scientist in me go to church next Sunday!
Again stable is in the eyes of the beholder. I define stable as a global temperature variation of 1C or less over a 100 year period, anything more I would say is not stable.
Well, sure, depending on the time scale. But still, total temperature variation of maybe 20 C over all inferrable time in the last billion or so years, over a period where the atmospheric chemistry and power output of the sun and radius of the moon’s orbit and configuration of the continents themselves all varied substantially? I call that pretty stable, even when it is currently bi- or multistable with a ~10 C oscillation.
below in second paragraph in previous post was rgtbatduke’s reply to me. Thanks for the reply.
Vulcanology and climate science are a perfect fit:
Sulfur Dioxide Emission Rate estimation caveat:
Starting in 2014, we report the emission rate estimated by a new, more accurate method. The numbers increase by a factor of 2-4 but the actual emission rate has not changed. For more on this reporting change, please read http://hvo.wr.usgs.gov/volcanowatch/view.php?id=207
One last item.
I think the delicate balance between the earth being in an inter-glacial state versus a glacial state makes the word stable in regards to climate take on a whole different meaning.
+1
Stable – not stable. Tomayto – tomahto. The only pertinent question is what causes that stability/instability and it’s rather obvious that it is not CO2, anthropo or not, or the other non-water GHGs.
Matt said:
Willis is right, this whole damned authorship thing has been bastardized to support the publish-or-perish meme. I doubt if all 4,000 of the LHC folks will have had anything to do with actually ‘writing’ the paper. The two or three or four (depending on complexity) actual authors that write the paper should be listed and a way found to credit the others with work done. It’s down right stupid to conflate research with authorship, they are two entirely different functions and capabilities.
In engineering development we had tech writers that, if they were good at their jobs, could tell a five year old how to program an iPhone to drive the family car around the block… and explain all the potential errors encountered. This (i.e., use of tech writers) limits what I call specialized language development where each new area of science (or engineering) tries to define its own (new) vocabulary (i.e., language) in order to appear important and fool the masses into thinking they know what they are talking about (and increase funding).
In other words “It’s the research stupid, not who writes it up.”
Here we go agin. I demonstrated that large volcanoes do not cause volcanic cooling but now these guys claim that it is the small ones that behind our backs do the coolimg. Have I said that stupidity annoys me? If not, make a note of it. The problem seems to be that they lack a basic understanding of what they are looking at when they see a global temperature graph. Specifically, they have no idea that a global temperature graph consists of a concatenation of ENSO phases, El Nino and LaNina, that alternate throughout the length of the graph. Unless they are specifically repressed to get a nice, smooth ciurve, the normal global temperature graph looks like a bandsaw, with saw teeth represented by El Nino peaks and the slots in between them by La Nina valleys. The actual graphs distributed also show a smattering of temperature lows that are said to be volcanic cooling. These “cooling” valleys are nothing more than normal La Nina valleys, attributed, by mistake, to some volcano that preceded them. Volcanic cooling does exist, but not down here, in the troposphere. All they had to do to know this was to read my book but apparently they are non-readers, in need of a course in remedial reading. The hot volcanic gases from an eruption go straight up into the stratosphere which gets hot. That happens aproximately at 22 kilometer height. Cooling follows a year or two later but it cannot descend down past the tropopause and just hangs up there. As to the blockage of sun’s rays, it appears to be no worse than that from a medium-sized cloud that keeps happening all the time. We would be completely unaware of all this if it wasn’t for those “experts” who have invented volcanic cooling. It is just another failed hypothesis, in a class with that of greenhouse warming. They have had plenty of clues that they are mistaken but they simply haven’t got the stuff to pick them up and use them. They have noticed, for instance, that some volcanoes are followed by volcanic “cooling” while others are not. Occasionally they will draw in an imaginary cooling that does not exist to correct for “errors” of measurement. This is particularly likely to happen with climate models where all the volcanic coolings are built into the code. The myth of volcanic cooling probably originated when someone noticed that a nice deep valley followed a strong volcanic eruption and appropriated it for the volcano. Later someone discovered that another volcano was not at all followed by any such valley. They admit now that both cases happen but they have no idea why. Here is the explanation. If the eruption coincides with an El Nino peak there will be a La Nina valley right next to it that looks like the work of a volcano and quickly gets appropriated for it. This is what happened with Pinatubo. But if an eruption coincides with the bottom of a La Nina valley it will be followed by an El Nino peak and there is no valley you can appropriate for it. This is what happened with El Chichon. Self et al. who discovered and named the Pinatubo “cooling” event remarked about the strange absence of cooling after the El Chichon eruption. As to their stealing that La Niina for Pinatubo, they opined that “…Pinatubo climate forcing was stronger than the opposite, warming effects of either the El Nino event or the anthropogenic greenhouse gases in the period 1991-93.” That shows you the quality of “experts” we are stuck with. Just remember that there is no such thing as volcanic cooling. All volcanic coolings on record are misidentified La Nina valleys. The presence, absence, or size of the observed “cooling” depends entirely on the exact time of eruption in relation to the position of the ENSO wave train into which it gets interpolated. To learn more, read my book (What Warming?), pp. 17-21. The quote is from “Fire and Mud” p. 1109`.
Mosher says:
No. they would not have to show this.
Showing it would help, but its not necessary.
What’s important is total forcing.
Well, did they show that? i.e. that total forcing was different compared to prior time periods.
” Here we use lidar, Aerosol Robotic Network, and balloon-borne observations to provide evidence that currently available satellite databases neglect substantial amounts of volcanic aerosol between the tropopause and 15 km at middle to high latitudes and therefore underestimate total radiative forcing resulting from the recent eruptions.”
Lucky we have Willis!
“Steven Mosher
January 9, 2015 at 9:16 pm
What’s important is total forcing.”
What “forcing”? Or are you talking crap again…
Neither the strength nor the numbers of eruptions are important, it is their cooling effect that matters.
This effect can be measured through the global temperatures which, according to models, should have risen more than they did.
This fits perfectly well with data!
fait des commentaires sarcastiques
I would suggest the earth’s temperature is ‘stable’.
A controlled system is classed as stable if: After a transient input change, the system returns to its ‘required’ value without sustained oscillations.
And that is what happens, in the geological time scale, something happens to perturb the temperature and after a few decaying oscillations, the temperature returns to a baseline of sorts.
In control speak, this is stable.
Large volcanic eruptions have and will always cause cooling that is a 100% certainty which is rare in the climate arena.
Small eruptions however will not have much of an impact on the climate because the SO2 particles do not reach high enough into the stratosphere.
The stability of the climate here is my response to that
The bottom line is the delicate balance of the earth’s climate from a glacial state versus an inter- glacial state NEGATES the notion that the climate of the earth is stable.
By the way I think a stable climate is one in which the temperatures varies by no more then plus or minus 1C over a period of a 1000 years. I had said a 100 years I meant a 1000 years.
Willis I am curious as to how you view my statement below.
I think climate sensitivity to various forcing is EXPONENTIALLY dependent upon the mean state of the climate/earth dynamics at the time the forcing is taken place which is why correlations are hard to come by and so many different climate outcomes (although a similar trend in a general sense) is always the result.
http://earthsys.ag.ohio-state.edu/ACES/ACES_curriculum_sections/ACES_HIGH_SCHOOL_ACTIVITIES/Volcanoes_and_climate_change.pdf
I subscribe to this study which talks about volcanic eruptions and their impact on the climate.
http://earthsys.ag.ohio-state.edu/ACES/ACES_curriculum_sections/ACES_HIGH_SCHOOL_ACTIVITIES/Volcanoes_and_climate_change.pdf
I am with this study on volcanic effects upon the climate.
Study??? That’s a bit of a high school curriculum, not a study of any kind.
w.
johnmarshall January 10, 2015 at 3:17 am
johnmarshall January 11, 2015 at 3:20 am
John, I took a look at your “excellent website”. His claimed source for the figure of 3 million undersea volcanoes is as follows:
Unfortunately, the work of Hillier and Watts is paywalled. However, that’s not the big problem. H&W’s abstract says:
So the source for the site you refer to says NOTHING about the 3 million active volcanoes that you refer to. Instead, it says that there are about 200,000 seamounts (extinct volcanoes).
In addition, that’s seamounts of all sizes, tiny to large. Note that they have included seamounts that are 100 metres high … 330 feet tall? That’s a pimple, not a seamount …
H&W also says:
So there are ~ 40,000 large seamounts. But again, that says nothing about volcanoes, just seamounts. Well, it does say something about volcanoes, because for every active volcano, there are lots of seamounts. Seamounts are extinct volcanoes, but unlike on the land, they don’t get worn away to nothing. Instead, up near the surface the unceasing waves grind off the top, giving them their distinctive flat-topped shape … but the rest of the seamount persists for millions of years because there are no erosive forces down deep.
So that means that there are probably a few thousand active undersea volcanoes.
Finally, I can’t find anything about seamounts degassing any significant amounts of CO2. Active volcanoes, sure, they give out CO2. But as far as I can see, extinct volcanoes (whether on land or in the sea) are a trivially small source of CO2. If you have information otherwise, then you should bring it forward.
In any case, your claim of three million submarine volcanoes is simply not true. Heck, according to your own citation there are less than a tenth of that number of seamounts even if you count pimples, and a tenth of those seamounts are large seamounts, and active volcanoes are perhaps a tenth of that number.
In other words, Robert Brown’s back-of-the-envelope calculation is about right … no surprise there.
w.
Quick calc:
Assume 53,000 miles of undersea mountain ranges (spreading or split crustal zone)
Assume 53,000 miles of trenches on the other side of each plate
Total =106,000 miles of splits or trenches, but the trenches will likely have volcanoes also, right?
If 106,000 miles of active seismic zones, then at 1 volcano per 20 miles (far, far more than up the western US coast, right?)
then you’d still only have 5000 volcanoes. And about half of those 5000 would be on land or right near island subduction zones.
3 million “lava seeps” or vents? No.
Leaving the volcano number argument the orriginal paper was about aerosols. Whilst volcanoes on land do preduce aerosols far more come from the oceans. These come from coastal surf zones, storm wave tops etc and include salt. Tropical aerosols are lifted high into the troposphere by convection and will affect weather.
You are talking about salt crystals. These are the most hydroscopic of aerosols. Their life as aerosols is measured in hours. They become condensation nuclei very quickly.
“Yet, there apparently is no such word as hydroscopic.”
…
Reference: http://dictionary.reference.com/browse/hydroscopic
There is now.
Let me get this straight: CO2 absorbs light energy and *warms* the atmosphere; volcanic dust absorbs light energy and *cools* the atmosphere?
tadchem, if by “light energy” you mean “visible light”, the usual meaning, then no. CO2 doesn’t absorb visible light. Volcanic aerosols, on the other hand, both absorb and reflect visible light, both of which tend to cool the surface. The net effect of eruptions on the atmosphere itself, however, is warming from the additional absorption of solar energy.
Regards,
w.
I’ve put an update at the end of the head post showing how trivially small the recent variations in stratospheric aerosol optical depth are when compared to volcanoes like Pinatubo.
w.
More support for Willis (I think) re Mount Tambora
http://wattsupwiththat.com/2014/09/19/laki-caused-1783-could-icelands-bardarbunga-volcano-trigger-another-year-without-a-summer/#comment-1742472
Mount Tambora
[Excerpt from wiki]
With an estimated ejecta volume of 160 km3 (38 cu mi), Tambora’s 1815 outburst was the largest volcanic eruption in recorded history. The explosion was heard on Sumatra island more than 2,000 km (1,200 mi) away. Heavy volcanic ash falls were observed as far away as Borneo, Sulawesi, Java, and Maluku Islands. Most deaths from the eruption were from starvation and disease, as the eruptive fallout ruined agricultural productivity in the local region. The death toll was at least 71,000 people, of whom 11,000–12,000 were killed directly by the eruption;[6] the often-cited figure of 92,000 people killed is believed to be overestimated.[7]
The eruption caused global climate anomalies that included the phenomenon known as “volcanic winter”: 1816 became known as the “Year Without a Summer” because of the effect on North American and European weather. Crops failed and livestock died in much of the Northern Hemisphere, resulting in the worst famine of the 19th century.[6]
[end of excerpt]
[Excerpt from my above post]
The Dalton Minimum had 2 back-to-back low SC’s with SSNmax of 48 in 1804 and 46 in 1816. Tambora erupted in 1815.
Two of the coldest recorded years in the Dalton were 1814 (7.75C year avg CET) and 1816 (7.87C year avg CET).
[end of excerpt]
Commentary:
So, for CET’s, it appears that the 1815 eruption of Tambora had minimal effect, since CET’s in 1814 were slightly lower than CET’s for 1816.
However, the anecdotal evidence suggests that 1816 was a much harder year for humanity than 1814.
What to believe?
Best to all, Allan
There is a fact that orbital stresses coincide with solar activity. When there is a change around a gravitational mass stresses increase, and when it balances out the stress decreases.