Volcanic Winter. Hypothesis and Candidates

A guest post by Tallis Rockwell

No one in the Byzantine empire knew why the sun didn’t shine in 536, why the weather was so cruel. Some thought that this was the day of judgment and angels would descend soon. That year it had snowed heavily in the southern dynasty in China which is the same latitude as northern Mexico. This year is considered to be the worst year to be alive. This event was the worst short term cooling event in 2000 years.

This event like the Byzantine empire doesn’t get the respect it deserves, and is the most fascinating (Likely) volcanic winter. What made this winter so much more worse than the others? The sulfur emitted was large but not as big as some other eruptions. Why is volcanic winter so variable in the first place?

Volcanic winter is the short term cooling caused be aerosols or other particulates blocking out the sun’s rays, the rather simple concept hides its infuriating complexity in real world application. Volcanism is an important variable in climate, just as much as CO2 or any other climate variable. The variables combine to make an equation, and the equation gives you a result. Short term cooling caused by large eruptions overpower certain variables particularly ones that cause warming but these eruptions don’t erase these other variables entirely. It makes since though their effects are masked or small, that these other variables either enhance or weaken climate effects of volcanoes.

The El Nino of 1982 is thought to have canceled out the effects of aerosol cloud birthed from El Chichon. What would have happened if there was a La Nina? Could the volcanic winter have been stronger than it was if the waters were neutral? This just shows that other climate variables do cancel out smaller volcanic eruptions, so it seems likely that the other variables have more subtle affects on volcanic winter.

The transport and environment of he aerosols and particulates that cause volcanic winter is usually governed by upper level winds. Active upper level winds would quicken the pace of the aerosols and effect there effectiveness to reflect light, concentration, as well as their lifetime in the atmosphere. This is a poorly studied subject as I could find very little information on this subject but hypothetically faster upper winds could lead to the aerosols being in constant state of instability leading to a longer duration but poorer concentration, likewise for slower winds more stability and greater concentration but poorer duration.

I believe this is why Mt Samalas didn’t have the extreme climate effect that some would think given how much sulfur was emitted. Due to this taking place in the medieval warm period, upper level winds weren’t as fast and the aerosols lifetime was shortened due to this. Nevertheless due to the sheer size of the eruption, it produced severe climate changes. My own personal hypothesis admittedly is based on little data.

Sea currents and volcanic winter have a well established relationship, the cooling from the aerosols affects the sea temperature and currents and capable of sustaining cooler temperature for decades but has anyone studied how sea currents and temperatures could affect a future volcanic winter? Warmer sea surface temperatures before the onset of a volcanic winter could lead to greater snowfall or land ice at higher latitudes due to increased moisture. Warmer oceans could also weaken climate effects from smaller VEI 5 to VEI 6 eruptions. The ocean is thought to moderate regional climate impacts from volcanic winter, this one of the reasons why some areas don’t suffer any changes, I think it is very possible that, while not as extreme, global sea temperatures could greatly affect the winter. Sea currents are a different story and a lot more complex so I am going avoid that entirely.

External affects on volcanic winter plays a more important role in the scale in volcanic winter then some might think. There is not a lot of data on this subject so we can use our imagination on how the other variables affect volcanic winter until another Pinatubo happens.

The aerosols of from volcanic eruptions are the dominant cause for climate changes, without them volcanic winter wouldn’t be a real threat. Each eruption has its own signature, is it possible that the aerosols emitted could have their own more subtle signature? Could aerosols from phreatomagmatic eruptions be more rich in water? Will the difference even matter? These are very small variables and the tiniest difference could lead a variety of effects.

How bad can a volcanic winter from an explosive eruption get? The best example I think of is the Toba super eruption. The climate effects are impossible to pin down as the Earth was in a period of long term global cooling and glaciation was in process, the climate at the time of the eruption was radically different then now.The cooling from the eruption is probably buried due to this and it’s consequences are hotly debated. It could’ve brought humanity near extinction or just dimmed the sun for a few years but for me neither side really has brought any conclusive evidence.

Well this sucks, the climate effects of the largest eruption in 2 million years are unknown and we don’t really want to analyze it through experience. According to some studies larger VEI 7 and VEI 8 eruptions could inject volatiles into the mesosphere. How would this affect the climate? I haven’t a clue.

Quite frankly, volcanic winter is a poorly studied concept and I don’t have any funding so I can’t actually test or proof any of my propositions. Some would think that a truly global disaster capable of collapsing empires and civilizations in a couple of years would get better research and respect.

Back to the 536 winter, I believe preexisting climate condition were perfect for volcanic winter. The sulfate spike for this event was not as big as Samalas but had worse consequences. Volcanic winter is much more complex then just how many aerosols there are but there is very little studies on why that is. This is my personal hypothesis on why volcanic winter is so variable.

How would a large scale volcanic winter effect modern society? This is a scenario of events based on my unfunded research on catastrophic events. This event is a Laki style eruption happening at the same year as a VEI 7 eruption. This isn’t impossible or terribly unlikely, Laki was just 30 years shy of Tambora and there was even shorter time frame between Eldja and Paektu. The volcanoes I will be using for this example are Katla (favorite Icelandic volcano) and Nevado de Toluca (Underrated volcano).

The build up phase of Toluca would be receive ample warning and study. Media attention would be rampant and full of warnings. A large eruption would be on top on scientist’s minds. The exact scale however would be harder to forecast and the government’s preparations without a clear forecast would be far too basic for a VEI 7 eruption. Katla’s phase would be much longer in duration and be taken more seriously by Iceland, and would inspire more anxiety as it would have direct effects on Europe.

The direct effects from the volcanoes would lead to thousands of deaths over a period of months, regardless of preparations. The scale of the eruptions would become top news and fears of volcanic winter would lead to a small or moderate global economic recession. The media would be split between people who say the climate effects will be moderate and ones who say that this is the end of the world.

The effects of the eruptions would be disastrous, The aerosols from the two eruptions would inhabit two different layers of the stratosphere and be very effective at reflecting light in the northern hemisphere. The winter following the eruption is cold but not disastrous and the populace’s anxiety would go down as result. The next year when spring comes along and temperatures don’t go up will inspire more fear. In tropical regions a severe drought encompasses farming regions. As a result harvests go down worldwide. This leads to a severe global recession surpassing the great depression. The red skies and faint suns decrease morale. Large scale riots take place in western countries as food no longer readily accessible and the recession causes soaring unemployment, the erasure of savings and instability within the government. The winter after the failed summer would be a brutal winter and with the unstable economies across the world leads to more fatalities and major damage to infrastructure. However there would be hope that the next year will be better.

The next year the populace across the world would be anxious and increasingly angry some people from higher latitudes would migrate down to escape glaciation or stubborn snow. The riots and storms lead to such damage that it could not be sufficiently repaired with the recession. Major businesses would start to go bankrupt and most private institutions would become nonexistent. That spring when another weak harvest takes place the governments would try get the angry populace under control. Civil unrest would take place and damage even more infrastructure especially the power grid. Some governments would collapse completely and most other countries would become ruthless in dealing with its people or its neighbors.. Basic necessities would disappear and famine would take over. Some would think that this is judgment day and God is coming. Communities of radical left wing and right wing ideologies would form leading to a division in some countries.

The bulk of the intense cooling would likely be over by the end of the second year but cool temperatures would be sustained for at least 3 or 4 more years. Even after the winter ends, there would be still extreme damage and the world would be changed. This would easily be the deadliest and costliest event in world history, thankfully a volcanic winter of this scale is unlikely and not something that should be expected with every dormant volcano’s awakening. Volcanic winter is something that should be studied much more than it is now, it is something that should be taken seriously and prepared for. Finally there are some candidates for large scale volcanic winter I would like to bring up. These are not volcanoes that I believe are an imminent threat but ones I think should be monitored and studied more.

Los Humeros

Los Humeros

A very overlooked volcanic field 180 km to the east of Mexico city was the center of several large caldera forming eruptions. The largest expelled 115 cubic km of magma around 460,000 years ago, smaller caldera forming eruptions took place afterwards. The last eruptions took place 20,000 years ago. This area is a geothermal goldmine and houses a very active hydrothermal field. The system however is still very much alive and has a massive 1,200+ cubic kilometer magma chamber. There has been no restless activity lately as such it is not a significant threat for the near future.(At the moment)

Alban hills

Alban Hills

This beautiful complex near Rome is a dangerous volcano and is starting a new eruptive cycle that is probably going to lead to large eruption. The shallow chamber 4-5 km below the surface has been growing for years. The region has been uplifted 50 m in the past 200.000 years and is rising at the rate of 2 mm a year. Still a large eruption is not imminent and this volcano could take a 1000 years to erupt. However volcanoes don’t erupt on easily predictable timescales, they erupt whenever they feel like it and this volcano is no different.



Another complex in the Mediterranean, I would call it the Ioto of Europe and unlike the others it has had a historical eruption. A very small one at that but this volcano is not to be taken lightly. This volcano has uplifted 800 meters in the past 33,000 years and has a very large plug. It does have a large magma chamber and extensive historical activity. No significant activity has been reported as of late and a large eruption may not happen for a while.

Tatun Volcano Group


Taiwan is not the place some people look for volcanism but it has a particularly interesting area. This area has two shallow hydrothermal reservoirs and a lack of good monitoring. There was phreatic eruption in 2014 but still there is not much information on this volcano. This area desperately needs more attention as just a moderate VEI 5 eruption could cause significant damage. Regardless of future activity this area is perfect for scientific study.

Volcanic winter is one of the biggest threats to modern society and essentially a guaranteed event but has no respect within the populace. Large scale volcanic winter is something to be taken lightly. Please tell me what your candidates for a large scale volcanic winter.

231 thoughts on “Volcanic Winter. Hypothesis and Candidates

  1. Well i never thought about 2 volcanoes impacting 2 different levels of the atmosphere… at the same time…. Interesting. and being in the northern area i guess i’d be one to be going south.

  2. Los Humeros, one of those volcanoes that maintain felsic and mafic active volcanism at the same time. I remember driving through those huge fields of young blocky basalt, it was amazing, mostly because of the surprise given that I had no idea I would find a volcano there. I didn’t learn until a few years later of the massive caldera that was sitting a few km away.

  3. If I remember correctly, there have been a couple of incidents in the last few years where livestock near Alban Hills have keeled over dead. Is this accurate or am I sim-remembering it?

    From the back-channel discussion.

    “367 A.D. A shower of hail fell at Constantinople [Istanbul, Turkey] on July 2nd. The hailstones were so large that it filled a man’s hand and each as solid as a stone. The hail killed many people and cattle.

    Winter of 400 A.D. / 401 A.D. In the winter of 401, the Pontus Sea (Black Sea) was frozen over, also the Sea between Constantinople (now Istanbul) and Scutari (Üsküdar) [inlet to the Sea of Marmara from the Black Sea] in Turkey.

    In the year 401, there was a great frost in the reign of Phocas it was the severest impact. The Black Sea was frozen for 20 days, and when the thaw came, such mountains of ice passed by Constantinople [Istanbul, Turkey] that they frightened the citizens.”

    A Chronological Listing of Early Weather Events 7th Edition, James A. Marusek

    I don’t remember directly, but I remember seeing an account in that text recounting reports of mountains of ice groaning as it rubbed up against the city walls {Constantinople}… and possibly visible above the walls.

    From the same reference re 590 Rome area;

    “After the flood, the river brought down innumerable multitude of serpents, and among them a monstrous great one as big as a great beam. All these serpents were swimming down the river into the sea, where they choked, and their carcasses being cast on the shore. There they rotted and by the stench of the slime and mud and excessive moisture, and the air was so corrupted, that a most desolating plague ensued over all Italy, Spain and France. The plague raged and laid waste to many towns. In many 2/3 of the people died. It was most severe at Rome, followed by Liguria [in the coastal region of northwestern Italy] and the Venetian territories [in northeastern Italy], both by floods, famine and plague.72 [The source identified this flood in the year 588 or 589.]”

    …so, if the flooding “carried away many thousand measures of wheat” from the granaries, one can only assume that it was scattered wherever the floodwaters went. I can’t think of a better way to feed hordes of mice and rats.

    For reference; Plague of Justinian (541–542 AD). Add a boon to the rodent food supply and it probably made the situation much much worse just a few years later. Any word on resurgence about 45 years after the plague started?

    Sure enough: https://en.wikipedia.org/wiki/Roman_Plague_of_590

  4. La Garita and Wah Wah springs produced 5000km3 to 5500km3 of ash from gas rich sillica rich evolved explosive eruptions.
    These enormous pyroclastic eruptions sourely plunged the world into a short lived near total darkness
    A short – 10 or – 12 C drop in global temperatures and little sun was result of these enormous eruptions.
    These very largest explosive eruptions resembeld an Asteorid winter rather than a normal eruption.
    But humans surivived Toba eruption

    La Garita was an enormous explosive volcanic event
    This global dispersion of ash and sulfates would have led to a sudden and catastrophic effect on the climate worldwide.

    Still the Chicxulub winter woud be much much much worse than La Garita or Toba

    • The biggest potential explosive eruption is a 30 million year old eruption in the red sea area which created the sam ignimbrite in Yemen, it has the possibility to dwarf la garita. There is a number on wikipedia that ranges up to 20,000 km3 of tephra.

      • Turtlebirdman do you know how much in km3 ejecta Chicxulub produced?
        I knows its alot .. but impact simulators dont tell the ammounts

    • Nevermind I think that was created by one of the volcanoes you mentioned.

      • Sam Ignimbrite is only 5000 to 6000km3 in most datas

  5. Escaping south… I wonder how much help the golf stream would give us in western Europe and Scandinavia? Also, how would the bioproduction in North Atlantic and Pacific oceans be impacted?

  6. As I understand it, corn production would collapse, as that is strictly a degree-day crop. There are several types of wheat, some more tolerant than others. Still likely to have scant crop first year, a poor, poor crop the second. I don’t know enough about wet/dry types of rice to even guess. Barley is the usual grain crop in cool/damp climates, as much, much more tolerant. Snag is conditions would be perfect for fungal contamination, the lysergic producing stuff…

    Also, Barley / rye production would be hard to ‘ramp up’ given the lack of warning…

    • The dark sun would hurt the crops that would usually be resistant to such conditions and without a stable economy, Barley production would be almost impossible to ramp up.

    • Note… I’ve read that the “dent corn” crop of either new Hampshire or Vermont was unaffected by “the year without a summer” and came in normally.

  7. Here are a couple off articles that deal with volcanic induced climate aberrations. The first is on the 536 AD timeline the second on Pinatuba. I wasn’t there for the 536 event even though some co-workers think so but I can attest to Mt Pinatubo. The area I live in, the Peace River Country in northern Canada had 3-4 years of extreme cold. -45C was the norm at nights with that temp. at times during the day, -52C was the coldest I remember being in. One city had 11 ft of snow. It seemed to snow almost every day. The snow lasted in places into July. Before that and after the winters were much nicer though long as usual. This area I think seems to be an area that responds to volcanic events and also to a good degree to oceanic temperature fluctuations. I call it ‘Little Siberia’.
    The article on 536 opens up the possibility that more then one eruption in the same hemisphere
    ( N or S ) can affect that hemisphere more than the other is new to me but does ring true to me. Two or three VEI 6-7 eruptions could well have triggered that disaster. If we had had another eruption on top of Pinatubo then we could well have had the same result. As to the consequences well?? My guess would be millions starving and we would welcome global warming back.


    • Although the chance of two VEI 6+ eruptions within a short time scale -ie close enough to keep an SO2 aerosol going for a more extended period- is pretty low, statistically, but that’s not to say it never happens. Rabaul + Ilopango, possible? It could almost have happened as recently as 1991, when Pinatubo was followed about two months or so later by a high VEI 5 from Cerro Hudson

      • … and that falls right into my other mantra… if there is a non-zero probability of it, that means it almost surely HAS to happen to SOMEBODY, at SOMETIME, SOMEWHERE… eventually.

        {Thank you Carl for the introduction to the idea of infinite probability, and to Albert for idea of “almost surely“.}

        Basically, nothing is guaranteed, but the likelihood of it can approach unity. (100%)

        Fukishima did this, if you look at it in the right context.

        Background: I’ve had a few courses on quality control while on active duty. In those courses, I learned about Dr Demming and statistical process control. This became endemic to Japanese auto manufacturing. How Japan managed to ignore the probability spread of a calamity such as 2011 Tōhoku earthquake and tsunami happening was beyond me. The seawall at Fukishima was only built to handle an 85% probable tsunami. (based on my calculations) What they got was larger than that. Albert pointed out to me that in the design process, they didn’t even use a statistical approach, they just built the seawall to handle the largest recorded tsunami in the pacific basin. So, it wasn’t a conscious decision to hazard the plant, they built for what they knew. No, I’m not any better at it, I’m just fulfilling part 3 of the Black Swan criteria, looking at it after the fact.

        It gets even weirder than this. Like a campy true to life Sci-Fi plot, ONE scientist gave repeated warnings to officials about the potential size of a quake that could be generated by the subduction zone just off the coast, but was pretty much ignored. Kiyoo Mogi. An expert in crustal deformation and originator of the Mogi-Yamakawa model (aka the Mogi Model), used to estimated magma influx into a volcanic system.

        “in 1978 Mogi was appointed to the newly created Earthquake Assessment Committee (EAC) for the expected Tokai earthquake, charged with warning the government if the quake was imminent. He went on to chair the ECA from 1991 until he resigned the post in 1996 after failing to persuade the government of the need to take uncertainty into account when issuing warnings.”

        As many of our longtime readers will know, uncertainty can really mess you up if you don’t allow for it. For example, volcanoes do NOT keep schedules… neither do earthquakes. (Hello Pacific Northwest…) Weather, another chaotically driven system, is quite adept at messing up predictions. (Hello MET and NOAA)

        An outlawed bumper sticker in Florida sums it up quite nicely. “Shit Happens.” ← Yes, you can be pulled over a cited for it. My apologies for the profanity here. If this gets redacted, it’s my fault, not the other moderators. Additionally, in Florida you can be cited for these as well. Though to be honest, compared to what some Icelanders drive for off-road fun, many of the US 4×4’s don’t deserve to have them and are just posers by comparison. Yeah, they may be able to deal with a mucky road, but lets see them tackle a cliff of tephra… {See! I kept it volcanic related… 😀 ) Note: One of the favored locations for this activity is an old sand pit/quarry near Hekla… so it’s the real deal that you see in these videos.

        • IIRC, those ignored Fukushima warnings are sadder because reactor operators, managers etc used to frequent a traditional restaurant in a nearby town set beside a shrine and high-water mark for the many, many victims of a prior quake / tsunami combo. Given this marker was set significantly higher than the Fukushima defences, gotta wonder …

          And, yes, placing essential reactor back-up systems at low level behind their sea-wall, where they’d surely be swamped by wash-over. D’uh, who ordered THAT ?

          Is there any equivalent to IgNobel prize for ‘Joined-Up Thinking, NOT’ ??

          • The pumps had to be lower because they needed to get to sea water. That is always the problem with nuclear: the need for cooling by ambient water. The height of the pumps had already been raised some years before the disaster, but not enough. It would be interesting to check how many nuclear reactors would be affected by a 1-meter rise in sea level. The new UK reactors are among them.

      • … so, if something extraordinarily strange lands in your front yard… don’t be surprised. It just happened to be your turn.

      • It also sort of happened last year, kilauea and sierra negra. Both of these eruptions would have had a massive effect on the climate if they were more explosive and sent their SO2 to the stratosphere, and not only did they happen in the same year but at the same time for most of their respective eruptions. It does seem pretty weird with how many times particular years can have more than 1 big eruption but most years have none. Also 1783, 1883 and 1983 are all notable years in volcanology too, different coincidence but interesting nonetheless (skaftar fires, krakatoa and the start of pu’u o’o respectively)

        Fissure 8 was going at over 50,000 tons of SO2 every day for about 70 days which is at least 350,000 tons of SO2 and maybe a lot more if the older part active in may had similar high rates. Maybe half as much again from sierra negra. Before this kilauea also erupted about 7000 tons SO2 a day too. Basically about a million tons of SO2. Not all the so2 erupts in an effusive eruption either a lot gets trapped or in this case probably in the ocean, if ut was explosive more of it would escape.

        I have seen information about what could have happened if kilaueas eruption was centered under kapoho, which to sum it up would have been most likely very explosive surtseyan to plinian eruptions and water amplified km tall lava fountaining and all this then sending that SO2 to the stratosphere in what would have probably been one of Hawaii’s biggest eruptions in millennia. Maybe hyping this a bit but still this could have been pretty serious, SO2 cooling the atmosphere and then what has happened over the US recently with the cold…

        • May have significantky underestimated kilaueas SO2 output for last year, holuhraun erupted 30% more lava and had similar SO2 flux, but apparently managed 11 million tons, so kilauea likely erupted about 7-8 million tons on equivalent. Assuming this is relativdly standard then suerra negra might have also dobe similar things and tgat eruption probably got to about maybe half the size of kilaueas eruption. In any case this is another double big eruption however you look at it.

          • 7-8 Mt of SO2 is probably about right for last summer’s leaky plumbing eruption.

        • sorry but your arithmetic seems not correct by an order of magnitude

          • Explain?

            The number for holuhraun is not mine it is the quoted number by most sites. Leilani was at minimum half the size of holuhraun and at maximum the two are almost the same size, and kilauea has the highest SO2 flux of any volcano measured so it makes sense.

          • I think this refers to your statement that “50,000 tons of SO2 every day for about 70 days which is at least 350,000 tons of SO2”.

          • That isnt what it looked like with the order of comments but im going to give the benefit of the doubt.

            In any case technically enough SO2 was erupted by kilauea and sierra negra last year to give an environmental impact pretty comparable to pinatubo despite the total volume being 1/20 as high. As said before too if last years eruption was 10 km east it would have been a very different story…

          • A high altitude plume from tropical blast is a pretty inefficient way to impact the weather in either the NH or SH. It first has to travel around the equator and then eventually get mixed up at the ITZ. Takes months to fully disperse across the NH and SH.

            A similar sized aerosol plume already in the NH or SH would have a much more significant effect within that hemisphere. Novarupta (Katami) for example.

      • Statistically, multiple VEI 5-6’s are much more likely than even one VEI 7.

  8. Though not a primary reference… https://en.wikipedia.org/wiki/Extreme_weather_events_of_535%E2%80%93536

    Was it in El Salvador, Central America ? There be monsters here…

    Given Chinese report of a ‘Boom from the South’, Was it Rabaul, one of the many ‘Usual Suspects’ along Indonesia’s ‘Ring of Fire’ ? If latter, did it blow itself clean out of the water, and the caldera is now submerged, eroded by the sea ?

    Was it a regular, Pinatubo-plus ‘Plinian’ to begin, then a second, cataclysmic, ‘Krakatoan’ event several years later, perhaps when eg a flank collapse opened access to the sea ? The differing spreads of ash, dust etc may be accounted by seasonal effects, a big typhoon etc. IIRC, the ‘fall’ pattern showed which season Toba blew in 70k BCE; As I understand it, could have been much worse if a few months sooner or later…

    Or was 536/539 two separate VEI 7+volcanoes, just bad luck that a pair should come along thus ?

  9. Just a note, there are some who don’t buy into the massive effect of volcanic aerosols. Based on a look at sulfate aerosols by Bluth, it appears that any SO2 injection to the stratosphere will be sedimented out after about 50 months to pre eruption levels. So the idea of a volcanic “double tap” seems to fit.

    How to read the plot. Green is the SO2 injection. As it converts to sulfate, it’s level declines and the sulfate concentration goes up. As the sulfate begins to sediment out, it’s level declines, eventually reaching pre-eruption levels. The plot is gear for a one metric tonne release so that the relative levels can be estimated no matter what the actual injection is, just use the plotted values as a percentage of the total injection. Either way, the greatest screening comes between 2 to 3 months after the eruption. (IF it reached the stratosphere.) If not, then the SO2 will be acted on much faster in the troposphere since there is ample humidity to react with. At worst you will see effects such as acid rain or harmful gasses impacting the flora and fauna. Sort of like Laki’s effects on Europe as the gasses made land-fall. (The mortality rate in France went up by about 5%) It got the crops and crop workers. So if you were a healthy worker breathing lots of air, you were more affected than someone who was sedentary.

    • In my opinion this is how it’s done. You don’t sit around fretting about it, you fix potential issues before it becomes a catastrophe. The officials there KNOW it’s just a matter of time.

      • Even a northern hemisphere one year harvest failure will cause the death of billions. Humanity is now completely reliant on arable farming to survive and this may well result in total failure after (say) a june frost over europe. Even as recently as 1900 there would have been enough livestock about to process failed crops into meat to survive at close to starvation levels but now there just isn’t enough. Whilst the southern hemisphere could help, they just do not produce enough to begin to cover a near-total crop failure in the north. Even the famous food mountains held by the EC years ago only ever got to about 2 weeks usage or so.

        Big population losses will happen in the near east, north africa and parts of s.e. asia. We may survive on palm oil ….

        • Mix in a “just in time” supply chain and the prospect’s get dismal quite fast.

        • From experience (hurricanes), expect grocers to be pretty much useless after about 4 days unless they have a really good resupply infrastructure.

          To give you an idea, this is the local grocer a couple of days before Michael when it still had a conceivable possibility of hinting in the Pensacola Area.

          If you waited too long to get your supplies, you were SOL. Water and bread are the first things to run low. This is the point where you start working out he time-distance logistics of the other stores in your area that might still have water in stock. A handy thing to pick up, is a manual piston pump adapter for a 5 gallon water jug. Having one of those expands your water options considerably.

          I was mainly amused at the water aisle, I keep 15 to 20 gallons of potable water stored here at the house and if pushed into a corner, I know how to make more given a supply of some sort of rainfall accumulation. UT might not sound tasteful, but ALWAYS keep a jug of UNSCENTED Chlorine bleach in your domicile. Micing ratios are readily found on the internet. If you have no bleach, clear plastic water bottles filed with sediment free water and left in the bright sunshine can become usable after a day or so of direct sunlight. As for the chlorine smell, let the water stand open to the air for a while and it will decrease in smell as the chlorine evaporates out. Back in 2004, I was without power for 5 weeks. The most dangerous bit was staying hydrated, but I had plenty of water. The other hazard were traffic lights. Florida DOT set up generators at the control boxes of the major intersections and kept the important lights running. That is when they weren’t replacing stolen generators.

          All in all, it depends on how well you think things out, how resourceful you are, and the general skill set you bring to the task. Having experienced FEMA in 1992 after a tornado, I opted for 15 lbs of potatoes just in case FEMA performed as well as in 1992. As long as I had fire, I could eat. My gas didn’t run out because I had topped off my tanks a week before Ivan entered the Gulf of Mexico. But if I did, I still had a Dutch Oven and a chainsaw with lots of oak laying about. BTW, you may have a lighter, but a Bernzomatic™ Propane torch make getting a usable fire started much easier to do. you can pick one up in most hardware stores. Brand is not important as long as it is reliable. Since my grandson is now a qualified welder, I may ask him to make me a small tripod stand for my dutch oven. That would be handy to have stashed somewhere in the garage.

          Oh, and the most amazing thing during Ivan. Having been though several USN Damage Control training courses… I quickly set up K type shoring for my garage door to give it added support in the middle from the wind. Ever since I had retired, I had figured that was a skill I would never need again. I was wrong. 😀 I was quite glad to know how to overcome that potential hazard. The down side is that my Bronco out in the driveway wound up being the thing that saved my roof. I kept one of the oaks that fell from rolling the rest of the way onto the house. I miss that little truck. Had it for 14 years and it had a fairly new engine in it. (Replaced about a year before I retired up in Jersey)

          • Side note about the empty water shelves above. Based on previous water “runs” on this grocery store, I knew that this chain would have pallets of water available in a day or so. They lived up to it and had about 5 pallets at the end of the aisle the next morning. (and at a lower price than the normal stock :D)

            Note: By Florida law, they can not jack their prices up during an emergency declaration. There is a nearby auto dealer that occupies what USED to be a gas station. FDLE had them for lunch when they were caught gouging during one of the close approach tropical storms that we get from time to time.

        • If the next volcanic cooing can just hold off for another 100 years or so, there might just be enough global warming by then to have created a lot more arable land in Greenland, Canada and Russia.

          ….so headline from 2150…”Global Warming Saves Humanity from Volcanic Disaster”

        • I prefer rye. With mustard, single slice as a snack. Toasting optional.

  10. I have a spreadsheet on my computer that plots the human population increase from 500BC to 2000 in 50 year increments. When the exponential growth is projected to 2200 by dragging the column an extra 4 rows from 2000 it shows a sudden drop to 1.365 billion by 2050, slowly rising to 1.462 billion in 2200. The resulting graph shows a trend to plateau under 2 billion, which is probably a sustainable global population.

    I think the UN projections of the global population neatly tapering off to a plateau around 11 billion and then slow declining is a mathematical fantasy. Exponential growth does not generally plateau like that; it tends to fall off a cliff. There are too many negative factors at play to avoid disaster. There too many nuclear weapons in too many places, with too many conflicts, narcissistic leaders and possibilities for miscalculation and irrational behavior without factoring in the potential for volcanoes to cause a volcanic winter or getting toasted by global warming.

    I put the probability for the collapse of civilization at 100% by 2050. It might be useful to start defining and planning a model of ecologically sustainable, economically viable and socially just civilization we would like to build in the ashes. It will not happen by accident.

    • Peter, you are right.

      Circa 2B would be a reasonable sustainable technological world population but not what will happen.

      What will happen, at some point, is mass migration due to lack of resources followed by collapse of technological societies and then another crash to populations sustainable by a technology at about the level or europe in the 1500’s. Allowing for drought, pestilence and disease (for humans, plants and animals) this means circa 15M for the UK, and not a lot for the middle east and disease-prone parts of the tropics.

      Whether, without a good and east to obtain supply of coal and oil (now all gone), humanity will return to a technological society is perhaps debatable. Remember the poorest in the fully developed world lives a better and healthier life than most monarchs of 1500’s.

      • Yeah. I’m an incurable optimist. Hope I live long enough to see which way it pans out; but I’ll be long dead by 2050.

      • The collapse of the current unsustainable model of civilization, by whatever means it occurs and the subsequent death of at least 2/3 of the global population (including me), is the solution, not the problem.

        • If that happen then let it be through the glorious power and awe that large volcanic eruptions produce and not some drug resistant virus.

        • Or other things. Scaring the population into not breeding might work.

          Unrelated, other than the title making my point. {…and evidently, some good things do come from California after all}

    • The “UN projections of the global population neatly tapering off to a plateau” is probably related to the error function. It shows up quite a lot in natural processes. It’s also generally sigmoidal in shape. Sparks used the sigmoid shape to describe the bubble nucleation rate in a forward that he wrote for a book on energetic volcanic eruptions. The funny thing about a sigmoid, once you cross a critical threshold, the system seems to avalance to a new stable state. From what I understand, the error function also a good model for describing neuron firing events as the various chemical messengers accumulate and eventually cause it to fire.

    • If you listen to the singularity guys, you are within a decade of the time when the rules for everything change. Cheers –

      • All part of the Great Enlightenment. As you may know from the process of hitting your head against a brick wall or being beaten with a bamboo stick by your local Zen master, it is often necessary to experience the consequences of your ignorance to truly understand a thing. It is not for nothing that we are hard wired to avoid unnecessary suffering and seek contentment from the satisfaction of our reasonable needs, wants and potential.

  11. All this negative outlook on the future is literally the exact stuff I would have obsessed over before last year, the amount of useless ‘apocalypse knowledge’ I have would make me a king in the real thing, literally everything made of steel that I saw was checked for carbon content to see if a viable sword could be made of it…
    My future house was going to be a solid concrete (2 meter thick external walls) castle built on a granite plateau that had 3 inch thick titanium plate on all sides as well as Al2O3/AlN ceramic as the windows, seriously this place could probably survive being shot at with a tank, and it would have only cost 3 million AUD.

    That being said now I think trying to devote to preparation is a terrible idea, prepare by all means but it means NOTHING if you are like 70 when it does happen. I used to want to live to be 101 so I could live into the 22nd century, but now that I have done things in my life that are actually productive and have a more positive view on the world I live in, I would rather die at 30 than live to 100 the way I was before (I’m 20 now). Obsessing over all this is not healthy and I think a few people here really need to have a good look. 2050 is 30 years away which is 30 years you could be living a life that is generally way better than any amount of preparation can give you if a real apocalypse happens.

    – someone who at one point literally complained out loud over N.Korea and the US managing to come to a peaceful agreement……

    • I stopped obsessing with this quite a while ago. The probability of my death is 100%, and I can’t know when its going to happen. It could happen next minute, next year or in 60 years.

      For me, it’s far better to learn how to live relaxed and healthy. By removing most stress of my life, having enough financial resources, and eating/sleeping well and doing physical activity. Simple stuff.

      When i lived in Iceland, and in 2014, I faced the government call for stockpiling because of the high likelihood that Bardarbunga could had experienced a caldera VEI6 eruption and I would be getting half a meter of ash over my house back then. Instead what I lived were weeks of poisonous gas due to Holuhraun and a few days where I couldn’t go outside of my house without a gas mask (and opening windows would unleash hell inside my house).

      At the moment I do not worry much about the most likely disaster waiting to happen, which is Brexit.

      About the agreement between US and North Korea, I think it’s a relief for mankind. But the madness still is around, and we need leaders with a motivation for peace rather than an inclination for war. Far too many countries are inclined for war. And then there is also climate change, another big threat for mankind. But there is little we can do about it. It will most likely happen. Volcanic winters are a threat less likely to happen, and if they happen they will only trigger the sheer fragility of our civilization.

      I have been amazed by the events of 536. Seem to have been quite a thing.

      Living happy in the here and now is the most important thing.

    • i am not as pessimistic. We have big problems coming up but they are solvable. The main risk is that we deny the problems – that would make them unsolvable and eventually, deeply damaging. The two big risks are climate change and population rise. Both can be addressed. Population nowadays depends mainly on fertility, as child mortality is way down and life expectancy reaching a plateau. Fertility rates depend mainly on education. Get more people into more education, and population growth will reverse. There are four scenarios below: the middle two assume that education levels remain constant, the first assumes extrapolation of current trends, and the last one assumes a push to enhance education levels. Pick your choice.

      • Funny that… using the birth rate by month of various countries… we “modern” hominids tend to breed the most during “Barbque season) and at something that seems to coincide with “Harvest Season” and festivals. Nordic countries tend to have their peak around the summer solstice.

        (Note, I only looked at the US and the Åland Islands.) Data was from here if you want to play witg it. http://data.un.org/Data.aspx?d=POP&f=tableCode%3A55

        Just back out 9 months for the indicated birth month to get an idea of the countries “breeding season.”

        An artifact of Florida’s TAG system, is that your tag expires during your birth month. Noting the month of a vehicles tag expiration date and you know about when during the year the owner was born… and with some quick mental juggling you can tell you about when during the year their parents were getting randy. And no, I haven’t seen a pattern between that and driving idiocy. But you know I’m looking for a correlation. 😀 (Observer bias, I know, I know…)

    • I stopped obsessing about it when I was 20 too. That was 50 years ago and I have had a good 70 years relatively free of woe. I merely observe and note that an ecologically sustainable, ecologically viable and socially just global civilization will not occur by accident. It has to be a goal of every tier of government and requires attitudes, values, beliefs and resulting behaviour from every individual that is consistent with that outcome. There is Buckley’s chance of that, so humanity will take the hard road; which involve a lot of unnecessary suffering that we are hard wired too avoid. My personal planning for inevitable disaster is simple – resignation.

  12. Populations fall when women are not considered to be brood cows but valuable income-generating members of the family and society. You can tell when this happens, families spend the same amount (in money and effort) educating daughters as sons, and care equally how well they do.

    Its what I noticed in SE Asia and the caribbean and is notable by its absence in many other parts of the world. This assumes that effective and viable birth control measures are easily available at the same time.

    Essentially that’s all you have to do.

    PS Some families, even in the UK, care not one jot about education.

    • I think it is not just income-generation, but self esteem as well that is important. I read a study that looked at the impact of China 1-child policy. It claimed that the impact was zero: the number of children would have declined the same, as education levels improved. In Africa, fertility levels stopped going down from 1995 to 2005. A recent study attributes that to the wars in the 1980’s, and claims that the declining trend has now resumed. The UN’s forecasts are based on the 1995-2005 fertility plateau, and they predict 4.5 billion people in Africa in 2100. Forecasts on more recent numbers are 1-2 billion lower. A bit of education can make a lot of difference.

      Yes, the UK has its problem pockets. The previous government had the sure-start centres which really helped. They have now all closed. A local nursery which focusses on poor children (for whom the council still provides grants) has just been told the same council wants to rent out their premises on the commercial market, meaning they would have to close. How is that for joined-up thinking. Most nurseries here survive only because they are in premises that subsidise them, mainly community centres or churches. A lot of them are threatened because many of the locations may close.

      • The biggest problem with the one child policy in China is not the overall demographics of the situation, although that is a problem. The biggest problem is the gender imbalance it caused. Female children are less wanted in China, so if there was a choice the one child ended up male. Gender-selective abortion and infanticide. Wonderful consequences of that policy leading to a whole lot of excess males sloshing around in China. Having excess males around in the population like that does not tend to have a happy outcome. Wars tend to happen as a result.

  13. Warning! A quad shot of espresso in the evening is not conducive to a good night’s sleep. (I just wanted to see if it made palatable espresso)

    And as normal, I picked the darkest meanest roast I could find… idjit me.

  14. https://www.facebook.com/dane.dupont.731/videos/305977740271374/

    On facebook so some of you probably wont see this, but finally there is a 3d model of fissure 8 and the 2018 eruption. It is actually a bit bigger than I thought it was, about the same size as pu’u honuaula (hill behind PGV) which is about 50 meters tall on some sides. I think it only looks smaller because the eruption happened in a low spot while pu’u honuaula looks like it formed on a pre-existing ridge.

    Also some more names for fissure 8.

    Maybe not quite a genuine mountain like paricutin or 1980s pu’u o’o but now I finally have a (technically) accessible named volcano that is younger than me 😀

  15. Kilaueas deformation over the week leading up to May 8 2018, fault lines and craters shown, as well as names of notable areas. Interesting how perfectly the places line up… In hindsight this could have been a warning of what would happen. It also shows that the area of magma storage extends beyond the caldera to the south and even a bit west, so if a full scale large caldera collapse does happen in the future it will probably be south and maybe a bit west of the caldera that is there now. The south caldera wall and ring fault where deformation is still happening might be particularly at risk of eruptions in the future, likely whatever happens the initial resumption of activity will not be quite or gentle but more abrupt and like 1952 or 1959, if it was going to be gentle it would have started again by now.

  16. https://m.facebook.com/story.php?story_fbid=1451821578286688&id=100003765788133

    Lots of stuff about Hawaii I know, but you know me 🙂
    This is significant as far as reactivation is concerned, especially having the deep rift connected to the area under pu’u o’o and the fact that inflation on the rift is faster than the rate of south flank movement.

    I think that these observations, even if far from imminent eruption levels, still show that the long period of relatively low activity after 1840 is not a product of that eruption damaging the system but rather a coincidental large eruption followed by diversion of magma to mauna loa at a depth far beyond the influence of either volcano, that is to say that mauna loa basically would have erupted in about 1843 anyway regardless of an eruption from kilauea in 1840 or not. The very well observed eruption in 1960 was not actually much smaller than 1840 and was much more powerful (knowing how much of fissure 8s lava is underwater the same thing probably happened in 1960 too) and the large deflation that happened afterwards, that took a year to reverse, ultimately did nothing to slow kilauea at all, even more importantly neither did the still larger eruptions before 1790 which are probably the best analogue to last year that data exists for. Inflation at jonika station was observed within a month of the eruption ending too, that doesnt sound like a decrease in supply to me. In the end it might still be a while before an eruption actually happens but it isnt going to be decades off thats pretty sure at this point.

    Seems like every time I try to stop talking about kilauea something new happens there…

  17. An explosive eruption like La Garita or larger woud be disasterous in short terms.
    Sam Ignimbrite is 5000 to 6000km3 in most datas.
    All ash in the atmosphere blocks sunlight.

    The short term global cooling is more than 10 C
    that causes an enromous farmine as crops fails and freeze.
    A similar effect occurs during an impact winter.

    Still La garita did not cause the oligocene disaster.
    Oligocene caos was caused by cooling climate and drop in co2 levels and the death of the Eocene global rainforests. In 400 million years the brigthening sun may bring back a constant eocene greenhouse

  18. for me a strong candidate would be the uturuncu volcano.

  19. Grimsvötn may become like a huge subglacial Mauna Loa – Kilauea mix IF the Icelandic hotspot keeps getting stromger and more estabilshed, its already an extremely strong plume.
    In the far future Iceland will take Hawaiis place in master of magma supply

    • To me, Iceland already surpasses Hawaii. The iceland hotspot supplies magma to 5 major volcanoes and a dozen dormant volcanoes while Hawaii only has to supply two major volcanoes.

      • Except one of those volcanoes in Hawaii has erupted about twice as much lava in the past 10,000 years as all of Icelands holocene volcanoes put together.

          • Because the rift allows passive magma accumulation which means this magma is likely not eruptible, at least only a small part is. Also no none have a magma chamber anywhere near that big, maybe some over 100 km3 but 1000 is really pushing it, grimsvotn is maybe up to 400 km3 being generous. And eruptible magma is usually the standard to measure a volcanoes productivity in which case there is no comparison.

            For the record, at the rate it is going now kilauea has probably been supplied with over 2000 km3 of magma in the past 10,000 years. Nearly all of this erupts eventually (much of it probably underwater before about 2000 years ago) because its rifting is driven by pressure of intruded dikes rather than passive spreading tectonic plates.

          • I should have used better language but the reservoir I was speaking of doesn’t have a volcano yet and i am strictly speaking of magma supply not erupted magma

          • Hawaii winns .. No other volcanoes can compete with Hawaii in long terms

          • Hawaii has a deep magma body too, below the big island. It also extends out under maui too, which is why haleakala is still an active volcano.

            Another way to look at it, Iceland is mostly basal non-volcanic (meaning not erupted lava, it is still igneous rock) crust with volcanoes on top of it, probably very similar to how the first continents formed. Hawaii is literally a pile of erupted lava that grew through the same stages as any other volcano but fed on the same sort of magma flux rates that could support a flood basalt province if it was able to collect in one place. As said before kilauea gets a few thousand km3 every 10,000 – 15,000 years or so, many actual flood basalts probably went 10 times longer than that between flows of that magnitude. Columbia river province has about 50 known 1000+ km3 flows over roughly 3 million years, about the same volume as kilauea, but kilauea is only 200,000 years old, about 15 times younger. Ever since the point I realised that literally no other volcano has seemed impressive anymore. Kilauea has done the DRE equivalent of a VEI 4 eruption in 4/5 of the years between 1952 and now, including every year after 1983, and then immediately afterwards did a large VEI 5 equivalent last year. Mauna loas eruptions are also almost always equivalent to a large VEI 4 or 5.

            Iceland also has a spreading ridge in conjunction with a plume while Hawaii is a plume all on its own and yet is still much more productive. Hawaii is also probably the hottest mantle plume at close to 1600 C under the southern part of the big island where the deep pahala quakes are.

          • The discussion was initially about supply, and I don’t know but Iceland probably does better. Some things are obvious, first Iceland can do bigger and more frequent explosive eruptions, the presence of felsic magmas and the subglacial setting of many volcanoes are to blame. When Mauna Loa had an ice cover explosive activity was very frequent and the Pahala Ash formed. Yes, Kilauea can do explosive too, but it is going to have a local impact, as will large earthquakes and lava flows. Iceland can do VEI 6 and VEI 5 eruptions, above the potential of Kilauea.
            Hawaii lacks large reservoirs of magma (there is no evidence for any storage that extends into Haleakala) but has a gargantuan output of lava, this is due to having the most active volcanoes of the world. The magma chambers are emptied and replenished very fast, they collapse and rebuild themselves sometimes in a matter of a few decades, we have seen many summit collapses of varying sizes (1790, 1823, 1832, 1840, 1868, 1924, 2018), it is less known but Mauna Loa has also had 2 pit craters formed historically. If one volcano is dormant it is because the other one is showing off and taking most of the magma from the source area, currently Kilauea is dominant and Mauna Loa “dormant”. Hawaii and Iceland have very different kinds of volcanoes, it depends on how you approach the situation, each of them stands out in a different way.

            Los Humeros certainly has the potential to put a big explosive eruption but note that most of its activity consist of basaltic effusive eruptions, it has had some of these during the Holocene though one of them started trachyandesitic and plinian, 6000 yr ago, weird eruption, happened from 3 vents 6 km appart and combined different eruptive styles and compostions.

          • Hawaii can probably do eruptions bigger than what has happened last year. Panaewa is one but kilaueas LERZ is entirely less than 500 years old and eruptions on this sort of scale probably happen less frequently than that. the eruptions that made the caldera in the 1500s were likely at least comparable to last year and probably the last one made halekamahina which is much bigger than ahu’aila’au and probably formed out of sustained and very powerful lava fountains.

            Many eruptions on the puna ridge could have been very big too. And then of course we have the lava shields which pu’u o’o is the biggest on the rift and is about 9 km3.

            Lastly I think VEI 5 is not out of the question at least for kilauea, some of its older eruptions probably got close at least and if somehow last years eruption was entirely phreatomagmatic it would have been over 3 km3 of magma. That last scenario was actually a more real possibility than a lot of people realised at the time.

        • In my opinion, there is a good chance that the 536 period was primarily caused by Mauna Loa.

          • Not pushing at all.

            2 Questions:

            What’s the largest active volcano in the world?

            What was happening at said volcano around 1500 years ago?

          • Not a bad train of logic. Oral history might shed some light, but it tends to turn into myth and folklore over a long period… provided anyone was around to see it.

          • 1500 years ago was basically mauna loa having its own version of pu’u o’o but it was not as voluminous and much more spread out. Panaewa might have been more significant but not like 536 describes. Also kilauea is the second biggest active volcano (its at least in the top 5) so by your logic that makes it a viable suggestion too, hawaii isnt going to change tge earths climate.

          • Agreed. Kilauea is also a theoretical contender. Just not for this particular time frame.

          • All I am saying is I think that the potential impact from the single biggest pile of lava the world has seen since the Deccan Floods should not be dismissed out of hand.

            Over 200,000 cubic kilometers of the stuff just on the Big Island. That does not even include the amounts that ran into the ocean.

  20. Hawaii is the strongest hotspot, but Iceland is the worlds second strongest oceanic hotspot

  21. looks like HVO is not reporting recent quakes. You can go to usgs earthquake map to see the recent quakes.

  22. In recent conversations here about plumes from the core through the mantle, this research casts interesting light on it:

    The two main layers of the mantle may not mix. Which (my hypothesis…) means a plume from the core may pool at the 410 mile boundary and inspire a second plume from said boundary to the crust.

    Regardless of my hypotheses, interesting reading!

  23. Another M4 aftershock of the Alaska earthquake. The number of aftershocks is much lower now but there remains a chance of a few more shocks of this size in the next few months.

  24. I read that earths core surface is covered by a forest of Iron crystals thats stands in the 5800 C soup of the inner liquid core.

  25. Candidates for a large scale volcanic winter? Any Indonesian stratovolcano with a height of 3,500m or more. Plenty to choose from 😉

  26. Yes Hawaii is the most powerful mantle plume
    And have erupted more lava in holocene than all other holocene eruptions from all other 1500 subarieal volcanoes combined.

    Correction here Icelands crust is volcanic its made of plateau lavas thats piled on eachother in flood eruptions. The holocene output from Vatnajökull is around 500km3 in forms of ash and subglacial emplaced lavas.
    Iceland is the 2 th most powerful magma source

  27. Icelands total holocene output is around 400 to 520km3

  28. from IMO
    18.02.2019 22:01:40 63.666 -19.108 1.5 km 3.0 99.0 7.6 km ENE of Goðabunga

    • Short swarm ending with the star. Most of it steam explosions?

    • The typical explanation is “underplating” but I suspect that some of it may be slab stacking. Back during the time of the Iapetus Ocean, there was a subduction zone in this general area. My pet theory is that at some point, one of the slabs wound up as a layer under the oceanic crust accounting for the abnormally thick crust under Iceland. Right next door is the Jan Mayan micro-continent. An area of seafloor made up of continental material. Jan Mayan island (which lent it’s name to it) is just a peripheral feature on it’s far northern extent. Having a chunk of old subduction zone and/or continental crust material under Iceland can help explain Hekla’s occasional strange geochemistry.

      Carl is better suited to comment on Hekla’s odd chemistry than I am.

  29. Volcanic winter candidates… Obviously it can come from almost anywhere.

    With that said, not enough people consider Aleutians / Kamchatka volcanoes, but this region is responsible for an outsized proportion of large (VEI 6+) eruptions in the last 50k years. Lots of eruptions in these regions are likely not well studied as well.

    • Up until now it has been thought volcanic eruptions at that latitude could not have the cliamte impact of tropical eruptions. a rather recent study shows that subtropical and high latitude volcanoes do have pronounced climate impact. Which is not really surprising when you consider not a lot of those volcanoes inject large amounts of sulfur and the recent one that did (Laki) had a significant climate impact,

      • Laki had a major effect around the northern Atlantic, but probably not worldwide. Eldgja may have had more wide reaching impacts, affecting parts of Africa. To get a worldwide impact, a major tropical eruption is needed, and the evidence suggests that a VEI7 is needed.

        • The Laki sulfur spike in the Greenland ice suggests that the impact was likely to the entire NH. The wind doesn’t generally blow from Iceland to Greenland so to get the Laki sulfur to Greenland it would probably have needed to make the full round trip.

          Global impacts are relative. There is evidence that significant NH imbalances created by volcanic activity from both Laki and Eldgjá disrupted the water flow in the Nile thousands of miles to the south. A tropical VEI 7 is certainly one way to create a globally impacting sulfur cloud but it is not the only way.

          • From Iceland to Greenland can be either way, as the wind often is easterly around Iceland. But either way it is north of the polar front so does not imply that the ash/sulfur spread much further south. For Laki we know it did go south and affected western Europe. If it had happened in winter, that might not have happened. The water flow of the Nile appears to be quite sensitive to climate effects, probably because it depends on how far east the Atlantic monsoon reaches. That suggests impacts from Laki as far south as 20 degrees, but again around the Atlantic.

            If Laki had been a singular explosive events, all bets are off. It wasn’t, so the sulfur clouds stayed low and didn’t last too long. Eldgja may have been a bit worse: it was bigger and lasted a bit longer (2 years).

  30. Here is a more accurate list of recent Icelandic eruptions in 1900 s until today

    2014 Bardarbunga
    2011 Grímsvötn
    2010 Eyjafjallajökull
    2004 Grímsvötn
    2000 Hekla
    1998 Grímsvötn
    1996 Gjálp
    1991 Hekla
    1984 Krafla
    1983 Grímsvötn
    1981 Krafla 2 eruptions
    1981 Hekla
    1980 Hekla
    1980 Krafla 3 eruptions
    1977 Krafla 2 eruptions
    1975 Krafla
    1973 subaquatic eruption 5 km south of Landeyjar coast
    1973 Heimaey
    1970 Hekla
    1963-1967 Surtsey
    1961 Askja
    1947 Hekla
    1938 Grímsvötn
    1934 Grímsvötn
    1933 Grímsvötn
    1929 Askja
    1927 Askja
    1926 northeast of Eldey
    1924 Askja
    1923 Askja
    1922 Askja 2 eruptions
    1922 Grímsvötn
    1921 Askja
    1918 Katla
    1913 Austan Heklu
    1910 Þórðarhyrna
    1903 Þórðarhyrna
    1902 Grímsvötn

    So Iceland is fiesty too
    Very very active it is

  31. Why is it that mentally, I read Þórðarhyrna as Thordarhyrna, adding an ñ from Spanish for the n?

    Yeah, I know it’s flat out wrong, but the mental pronunciation makes it one of my favorite volcano names.

  32. Laki and Eldgja…. absoultely puny and insignificant compared to Pre – Opening of the atlantic 201 million years ago
    Central Atlantic Magmatic Province caused by the Pangea Superplume are the largest flood basalt lava flows to ever flow over land in recent geological history.
    Over a very short timespann as much as 15 million cubic kilometers of lava was erupted in short pulses.
    The lava flows are 60 meters thick and covered an arera 5800 km long and 3000 km wide.

    Single eruptive fissures must have reached 600 to 800 km in lenght in very largest cases
    The force of the eruptions shot lava fountains as high as 4000 meters into the air 13 000 feet.
    Curtains of lava fountains strecth across the horizon.
    out comes sheets of Aa lava and open lava channels that coud ahve reached 1700 to 2300 km long.
    Lava flow out as sheets flows from the fissures out that gets as large as Scandinaiva.
    pangea must have domed more than a kilometer before these massive eruptions broke out.

    Its the enormous Co2 gas output from pangeas rifting flood basalts that caused massive global warming in Triassic, in Triassic earth was as warm and humid as it ever can get just after these flood basalts.

  33. If souch a major plateau basalt flood happens again the world is in huge trouble
    Massive global waming and enromous sulfur chaos
    No signs it will happen now anyway.

    Today there is no supercontinent to overheat the mantle

    • I don’t really think that the CO2 caused by flood basalts are responsible for the postulated global warming. Large amounts of CO2 are released through every flood basalt yet only a few are the probable cause for extinction events.

      • The power of the CO2 from the flood basalt battlestations would have been insignificant compared to the power of the SO2.

        • Only true short-term. In the longer term, CO2 is far more important as it stays in the atmosphere much longer. There is no doubt that the heat wave after the Siberian traps was caused by atmospheric carbon, as shown by changing carbon isotopic ratios.

          • CO2 has historically been a lagging category when it comes to volcano-caused climate change. During the trap eruptions, the SO2 cooling would have trapped loads of the volcanic CO2 in cooler oceans and ice sheets. Once the eruptions stop, then oceans start to warm up and ice sheets melt and loads of CO2 is forced out of solution.

            As a lagging indicator, it is clear that CO2 does not initiate the warming. Shutting down the SO2 factory does that. CO2 impacts really hit as things start to warm up, possibly accelerating the warming until plants catch up to offset the carbon imbalance or the next volcano cools things off again.

            Difference right now is China is making CO2 a leading rather than lagging indicator.

          • The Siberian traps is a special case, everything generally caused by flood basalts were supersized in those eruptions. While i do think the CO2 caused warming, i don’t think it is enough to cause the damage that these extinction events represent.

          • Can’t beat actual numbers when making statements. How much CO2 was involved, and why do you think it can’t cause the post-flood-basalt warming? Clearly, the Permian was the most extreme case but warming spikes are not uncommon after these events.

            Regarding the lagging of CO2, that was true during the ice ages but hasn’t been for some centuries. The current warming follows the CO2 well.

          • CO2 energy absorption follows the beer lambert law. It eventually becomes saturated. The first 30ppm absorbs 50% of the energy in the spectrum. Each doubling absorbs half of the remainder. While increased temp also increases bandwidth, the proportion of OLR emitted in the CO2 band decrease as it corresponds to cold temp wavelengths. zonal/meridional circulation patterns(driven by continental placement) is the main driver of long scale climate. And atmospheric thickness with a constant lapse rate explains the faint young sun problem.

          • That is nonsense. If you put a thicker duvet on your bed you will be a lot warmer even though the thinner duvet already intercepted all the radiation from your body. The warming is set by how fast radiation gets through the multiple absorptions and re-radiations, and this scales linearly with the amount of CO2. You are using the wrong physics. Same as your house: the insulation scales with the thickness of the walls.

            And if you don’t believe physics – look at Venus. Much more CO2 – much hotter.

  34. Siberian Traps and Central Atlantic Magmatic Province
    made the earth unbearable hot and sulfur choked during the short times they where active.
    Flood basalts and continental breakup and superplumes are acossiated with high co2 and supergreenhouse phases.

    • The Siberian traps did happen during a supercontinent but it did not break up the continent. The Deccan traps happened after the supercontinent had broken up, but again it did not add to the break-up. Flood basalts can be associated with continental break-up (North Atlantic, South Africa, ..) but some are not.

    • … and based on recent reading, it appears that I live at one end of the South Georgia Rift. Most of the physical manifestation of it is about 15km under the sediment of the area.

      • Yes: there are many of these failed rifts in the world. I live in between two failed rifts: the North Sea and the Irish Sea. I think the majority of rifts eventually fail.

  35. A general comment: the system filter puts some comments in the ‘for approval’ queue. That happens to first-time commenters, to commenters which some discrepancy in their sign-in details, to comments with too many or suspect links, too many comments in a short period of time, or just because the filter feels like it. If you submit a comment but don’t see it appear, this is likely what happened and you will need to be patient. It may some hours before one of us notices that the pending queue has action items. Occasionally a comment may not be approved at all because it fails our first rule (‘be nice’) but that has been pretty rare (but our apologies about the occasional comment which should have been intercepted and wasn’t).

  36. Siberian Traps and Deccan Traps was very very powerful intraplate hotspots back when they where active.
    Today Reuinion hotspot is a ghostly shadow of its former self

  37. Siberian Traps did not break the siberian craton likley beacuse the litosphere was so thick right?
    But it did cause rifts during the upswelling of the crust.. but it never broke the litospheric plate into two

    • I recently visited the southwest USA and noted east of Las Vegas what seemed to be LOTS of volcanic deposits. Then the Grand Canyon which has risen “quite a lot” which suggests to me there is a lot of hot buoyant rock underneath. If so we really don’t want it breaking out.

  38. The Plummer ice core data suggests that “536” was actually towards the end of a significant and extended period of volcanic activity in the NH that really began in about 529. The sulfur deposits in the Greenland ice during the 529-536 were the largest, by far, over any similar time period in the entire 2000-year data set.


    529-531 was the biggest sulfur signature during this period.
    533-534 was next biggest
    535-536 was the last large sulfur spike of this period.

    For a variety of reasons, my guess is that Mauna Loa is THE leading suspect.

    • The main problem is that the Pana’ewa eruption was effusive so it doesn’t seem likely it would have had such a widespread impact.

      • The Pana‘ewa picrite flow was just ONE of the Mauna Loa eruptions roughly in this time frame and not nearly the largest. Based on its size, the lava that formed the Pana‘ewa picrite flow would probably have been from at least a 3-5 km3 eruption (not even counting the amount that would have disappeared into the ocean). Actually, based on what was seen in 2018 at Kapoho Bay, it is entirely possible that the eruption could have been even significantly larger.

        The Pana‘ewa picrite flow flow is a widespread, vesicular, olivine- and plagioclase-rich ‘a‘ä and pähoehoe flow. Lava erupted from a cinder cone at 6,020-ft elev. The flow covers 173 sq km and forms coastline from Hä‘ena (Shipman’s Estate) to Bayfront (Hilo Bay). Age, 1,470±50 radiocarbon yr B.P.

        I very much doubt that it just gently oozed out that much lava without some seriously gassy fountains of lava. And, again, this is only one of the Mauna Loa flows from roughly this time period and not nearly the largest.

        • No it was by far the biggest eruption, the eruptions before it might have erupted more lava overall but were slow effusive shield eruptions like pu’u o’o was and would have been going for years at low rate. Panaewa was like last years eruption but with more height difference.

          And also both last years eruption and holuhraun show lava can erupt at high rates without high fountaining too, and most if not all vents erupting at rates needed to sustain high fountains will thermally erode to a wide hole. This effect is particularly evident at fissure 8 and holuhraun. One interesting exception was kilauea iki in 1959 managing to sustain a continuous high fountain for a week but otherwise in most cases the vent basically becomes a big hole that lava gushes out of like a broken pipe. This almost certainly happened at panaewa after not very long (probably only a few days) and then it would have little if any significant SO2 input to the upper atmosphere.

          • 1. Hawaii is home to the biggest active volcanoes on the planet, by FAR.
            2. Hawaii’s volcanoes are among the gassiest volcanoes in the world. As much as 7-8 Mt of SO2 per cubic km of erupted magma.
            3. Historically, Hawaii has a tendency to behave far less “effusively” than it has since we started watching it in 1823.
            4. There are numerous confirmed and documented instances of jet stream interaction with plumes created by the more energetic historical version of Hawaii.
            5. Hawaii is home to the biggest active volcanoes on the planet, by FAR.

          • I am very aware of all of these things and I think some of those things you mentioned could have even been related to things I have said in the past but I still think saying mauna loa is the cause of one of the most damaging climatic events in recent time while the current comparable (and likely overall larger) episode from kilauea has done nothing at all is pretty slim.

          • Actually….I still agree with you.

            Kilauea is just as culpable. Not specifically for the majority of the 529-536 sulfur. But, overall, just as guilty in the past few thousand years.

          • Maybe if mauna loa did an eruption as big as panaewa but as a radial vent or low SWRZ eruption that was able to be phreatomagmatic, then it could have been more likely to do some climate stuff but given that an eruption happened in exactly that place in 1877 and was really tiny of all things maybe radial vents are just not usually very big. Mauna loa is also not going to get more active than it is now really, maybe every few hundred years it will peak but kilauea is stealing the show now and that is the volcano that probably has more potential in the future. Loihi will probably join in about 50,000 years too when it becomes shallow.

          • Mayber…but the plume height over Hawaii does not have to be as high as most people think to interact with the jet.

            D. Swanson…the west winds of the subtropical jetstream, which in Hawai‘i blow year-round at altitudes of 4-17 km (13,000-56,000 feet).

            Altitude depends on the season.

          • The time that the sulphate particles stay in the atmosphere depends on altitude. Mauna Loa may be able to inject them into the tropical jet stream, but if the particles are at say 8 km, they will drop down in weeks. They are affected by precipitation and storm clouds extend to very high altitudes in the tropics. To have long residence times for the sulphates, they need to be in the dry stratosphere, and that is at very high altitude in the tropics. Note that sulphate particles in the arctic can linger for very long times in winter even at lower altitudes, because there is so little moisture in the cold air. But that doesn’t work well in the tropics. For a tropical eruption to affect the climate, it should inject to ~ 15 km (rough number).

          • The Laki research suggests that a few “months” in suspension in the UT/LS is more likely. But ,suspension in the UT/LS jet stream for only “weeks” is still not a negative factor at all. It is the opposite. That is still more than enough time to do the damage. “Within weeks” is more than enough time to spread the SO2 plume to every corner of the NH. The problem gets exponentially worse if the source of the SO2 continues for a significant period……like Hawaii is especially suited for and capable of doing.

            Plus, even in a stratospheric blast, the high altitude just provides the distribution mechanism. The real SO2 impact still occurs in the UT/LS as the gas is filtered down over time. With a Laki (or Hawaii) the gas starts in the UT/LS so initial impacts specifically to the NH are even more concentrated and dramatic.

            The dogmatic assumption about the 16-18km tropopause altitude / barrier over Hawaii is frequently cited as a fact. Thus, many appear to have simply dismissed the possibility that Hawaii’s basaltic eruptions could ever have been even remotely as impactful as the Icelandic flood basalt eruptions or the big VEI 6/7 blasts throughout history.
            However, I strongly suggest the possibility that that this conclusion is entirely incorrect.

            Here is why. While the tropopause, globally, is generally higher than 30,000 feet at the 20 degrees north latitude of Hawaii, it is not always at that level, especially over the Eastern Pacific and Hawaii. And, in fact, it turns out that it is it folds down as it meets up with the ITCZ and jet stream. It is extremely common for the jet stream to move directly over Hawaii at pretty much any time of the year but especially from about September to March when it is cooler in the NH.

            It actually appears to be quite the opposite of it being a natural barrier. In fact, it appears that 20 degrees north and south latitude actually seems to be the sweet spot for a gas plume to enter the jet stream. The Hadley cell westerlies could even provide additional lift and movement toward the jet even at slightly lower eruption columns.

            No arguments at latitudes of between 15 degrees north (Pinatubo) and 15 degrees south. The tropopause is an insurmountable barrier to a NH /SH plume distribution from anything but a true stratospheric blast.

            But, far from there being an insurmountable barrier over Hawaii to an to an UT/LS jet stream distribution mechanism, Hawaii is actually in pretty much the exact worst place possible in the world for a giant SO2 factory. The unique location of Hawaii at 20 degrees north latitude and in the Eastern Pacific REALLY matters. It is very unlike Nyamuragira which is in about the best possible place for a large basaltic volcano …..right on the equator.

            Again, between 15 degree north and south latitude and, even farther north and south over other parts of the globe, it really does probably require a legitimate stratospheric blast to create anything more than just a regional / downwind impact. Even in the Eastern Pacific, just a few degrees farther south or a few hundred miles to the west and the atmosphere does indeed behave quite differently and the jet stream rarely dips down that far. Hawaii is in a unique location.

  39. Maybe….maybe not. This was from the tiny 1984 eruption.

  40. https://volcano.si.edu/showreport.cfm?doi=10.5479/si.GVP.SEAN198312-332010

    This is very interesting, all the way back in 1983 there was an intrusion down to the area just up from where jonika station is now, among the 1977 vents. I guess it wasnt technically a failed eruption because it hapened at the same time as episode 12 but interesting nonetheless. The fact it didnt become a new eruptive center at all probably means it was not very big but maybe in the long run this ultimately made the events of last year possible. There was also a tiny flow erupted in this area sometime between 1986 and 1988 that might have been a secondary eruption of this magma.

    This spot is also pretty much exactly where I have been saying a new sustained eruption could start in the coming years, it would follow on as a downrift progression of eruptive centers from mauna ulu to pu’u o’o and then this area in maybe about a decade or 2.

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