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.
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)
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.