There was a giant eruption of Campi Flegrei about 40,000 years ago. Just about the time the Neanderthal population plunged. This isn’t all that surprising when you consider that this eruption basically covered most of the Neanderthal range with ash, killing them and their food supply.
Some few survived around the edges, but then they blended in with new arrivals of Cro Magnon like peoples as the land recovered. Leaving a single digit percentage of Neanderthal DNA in modern Europeans and some Asians.
For some silly reason, this article talks about the Italian volcanoes, but has a picture of an Indonesian volcano. Go figure.
Volcanoes wiped out Neanderthals, new study suggests
October 7, 2010
University of Chicago Press Journals
New research suggests that climate change following massive volcanic eruptions drove Neanderthals to extinction and cleared the way for modern humans to thrive in Europe and Asia.
New research suggests that climate change following massive volcanic eruptions drove Neanderthals to extinction and cleared the way for modern humans to thrive in Europe and Asia.
The research, led by Liubov Vitaliena Golovanova and Vladimir Borisovich Doronichev of the ANO Laboratory of Prehistory in St. Petersburg, Russia, is reported in the October issue of Current Anthropology.
“[W]e offer the hypothesis that the Neanderthal demise occurred abruptly (on a geological time-scale) … after the most powerful volcanic activity in western Eurasia during the period of Neanderthal evolutionary history,” the researchers write. “[T]his catastrophe not only drastically destroyed the ecological niches of Neanderthal populations but also caused their mass physical depopulation.”
Evidence for the catastrophe comes from Mezmaiskaya cave in the Caucasus Mountains of southern Russia, a site rich in Neanderthal bones and artifacts. Recent excavations of the cave revealed two distinct layers of volcanic ash that coincide with large-scale volcanic events that occurred around 40,000 years ago, the researchers say.
Geological layers containing the ashes also hold evidence of an abrupt and potentially devastating climate change. Sediment samples from the two layers reveal greatly reduced pollen concentrations compared to surrounding layers. That’s an indication of a dramatic shift to a cooler and dryer climate, the researchers say. Further, the second of the two eruptions seems to mark the end of Neanderthal presence at Mezmaiskaya. Numerous Neanderthal bones, stone tools, and the bones of prey animals have been found in the geological layers below the second ash deposit, but none are found above it.
The ash layers correspond chronologically to what is known as the Campanian Ignimbrite super-eruption which occurred around 40,000 years ago in modern day Italy, and a smaller eruption thought to have occurred around the same time in the Caucasus Mountains. The researchers argue that these eruptions caused a “volcanic winter” as ash clouds obscured the sun’s rays, possibly for years. The climatic shift devastated the region’s ecosystems, “possibly resulting in the mass death of hominins and prey animals and the severe alteration of foraging zones.”
Now it gets a bit muddy on the name front. Same place has several different names. “Campanian Ignimbrite”, Campi Flegrei, The Phlegraean Fields . Don’t let that throw you. It’s the same place.
The Campanian Ignimbrite eruption (CI, also CI Super-eruption) was a major volcanic eruption in the Mediterranean during the late Quaternary, classified at 7 on the Volcanic Explosivity Index (VEI). The event has been attributed to the Archiflegreo volcano, the 13-kilometre-wide (8.1 mi) caldera of the Phlegraean Fields, located 20 km (12 mi) west of Mount Vesuvius under the western outskirts of the city of Naples and the Gulf of Pozzuoli, Italy. Estimates of the date, magnitude and the amount of ejected material have varied considerably during several centuries of investigation. This applies to most significant volcanic events that originated in the Campanian Plain, as it is one of the most complex volcanic structures in the world. However, continued research, advancing methods and accumulation of volcanological, geochronological, and geochemical data has amounted to ever more precise dating.
The most recent dating determines the eruption event at 39,280±110 years BP and results of 3D Ash Dispersion Modelling published in 2012 concluded a dense-rock equivalent (DRE) of 300 km3 (72 cu mi) and emissions dispersed over an area of around 3,700,000 km2 (1,400,000 sq mi). The accuracy of these numbers is of significance for marine geologists, climatologists, palaeontologists, paleo-anthropologists and researchers of related fields as the event coincides with a number of global and local phenomena, such as widespread discontinuities in archaeological sequences, climatic oscillations and biocultural modifications
Main article: Phlegraean Fields
The Phlegraean Fields (Italian: Campi Flegrei “burning fields”) caldera is a nested structure with a diameter of around 13 km (8.1 mi). It is composed of the older Campanian Ignimbrite caldera, the younger Neapolitan Yellow Tuff caldera and widely scattered sub-aerial and submarine vents from which the most recent eruptions have originated. The Fields sit upon a Pliocene – Quaternary Extensional domain with faults, that run North-East to South-West and North-West to South-East from the margin of the Apennine thrust belt. The sequence of deformation has been subdivided into three periods.
The First Period, which includes the Campanian Ignimbrite Eruption was the most decisive era in the Phlegraean Fields’ geologic history. Beginning more than 40,000 years ago as the external caldera formed, subsequent caldera collapses and repeated volcanic activity took place within a limited area.
During the Second Period, the smaller Neapolitan Yellow Tuff eruption (Neapolitan Yellow Tuff or NYT) took place around 15,000 years ago.
Eruptions of the Third Period occurred during three intervals between 15,000 and 9500 years ago, 8600 and 8200 years ago and from 4800 to 3800 years ago.
I note in passing that several of those dates seem to land on known cold periods with about a 4000 to 5000 year period.
The structure’s magma chamber remains active as there apparently are solfataras, hot springs, gas emissions and frequent episodes of large-scale up- and downlift ground deformation (Bradyseism) do occur.
In 2008 it was discovered that the Phlegraean Fields and Mount Vesuvius have a common magma chamber at a depth of 10 km (6.2 mi).
The region’s volcanic nature has been recognized since Antiquity, investigated and studied for many centuries. Methodical scientific research began in the late 19th century. The yellow tuff stone was extensively quarried for centuries, which left large underground cavities that served as aqueducts and cisterns for the collection of rain water.
In 2016 Italian Volcanologists announced plans to drill a probe 1.9 mi (3.1 km) deep into the Phlegraean Fields several years after the 2008 Campi Flegrei Deep Drilling Project which had aimed to drill a 3.5 km (2.2 mi) diagonal borehole in order to bring up rock samples and install seismic equipment. The project was suspended in 2010 due to safety problems.
Effect on climate
The climatic importance of the eruption was tested in a three-dimensional sectional aerosol model that simulated the global aerosol cloud under glacial conditions. Authors calculate that up to 450 million kilograms (990 million pounds) of sulphur dioxide would have been accumulated into the atmosphere, driving down temperatures at least by 1 to 2 degrees Celsius (1.8-3.6 degrees Fahrenheit) for a period of 2 to 3 years. The Heinrich event 4 (H4), the name given to a cooling period, characterized by a break off of unusual large sections of ice from polar glaciers occurred around 40,000 years ago being well documented in the North Atlantic Ocean, although its impact on terrestrial areas is a matter of ongoing debate.
Effect on living organisms
Sulphur dioxide and chloride emissions caused acidic rains, fluorine-laden particles become incorporated into plant matter, potentially inducing dental fluorosis, replete with eye, lung and organ damage in animal populations.
The eruption coincided also with the final decline of the Neanderthal in Europe. Environmental stress caused by the eruption has been invoked as a potential explanation for the extinction as well as discontinuities in Palaeolithic societies, although the climatic effects of the eruption alone are considered insufficient to account for the demise of the Neanderthals in Europe. The notion remains contested, nonetheless, some studies suggest, that significant volcanic cooling during the period immediately after the eruption might have severely disturbed these already precarious populations
In 2012 the GFZ German Research Centre for Geosciences has published a study on likely causal connections between the Laschamp magnetic reversal and the eruption as “sediment cores from the Black Sea show that during this period,  a compass at the Black Sea would have pointed to the south instead of north.” Evidence seems to be limited and the publication is no longer publicly available.
So all sorts of impacts and effects if this thing has a big blow.
So what’s happening now?
A year ago… but volcanoes can be slow and take many years to get started, even when ready to blow.
Dec 23, 2016 @ 02:45 PM 74,684
2 Free Issues of Forbes
Europe’s Most Dangerous Supervolcano Is Reawakening Just In Time For Christmas
Trevor Nace , Contributor
Just below millions of people there is a supervolcano that has begun to show signs of reawakening. The supervolcano, Campi Flegrei, is 8 miles wide and sits beneath the Bay of Naples offshore Italy. Recent monitoring of the volcano points to a reawakening of one of the largest volcanos in Europe.
An international team of geoscientists have monitored the volcano’s caldera for signs of activity and recently published results in the journal Nature Communications on the increased danger of an eruption.
Campi Flegrei, which means “burning fields” in Italian, is believed to have formed hundreds of thousands of years ago and has erupted on several occasions in recent geologic time. The initial eruption, which occurred 200,000 years ago triggered a “volcanic winter” from the massive amount of ash ejected into the atmosphere. The volcano then erupted again 40,000 and 12,000 years ago. The eruption 40,000 years ago is thought to have wiped out most of the European Neanderthals and was one of the largest volcanic eruptions of all time. In recent memory, Campi Flegrei erupted in 1538 for 8 days straight, sending ash across Europe and forming the new mountain Monte Nuovo.
Recent measurements from the Campi Flegrei volcano indicate it is approaching what is called the critical degassing pressure (CDP), a pressure at which the volcano can begin a phase of volatility and volcanic unrest. The CDP is generally speaking a pressure where volcanic gas can release from the underlying magma, heat localized hydrothermal vents, fluids, and rocks. This increased pressure and heat can trigger deformation of the overburden rock and ultimately rock failure, i.e. a volcanic eruption.
Scientists have measured accelerated deformation of the volcano, which has literally risen recently due to increased gaseous pressures. Scientists have measured a 1.25 feet rise of the volcano’s ground since 2005. Gas at high pressures in the subsurface is exceptionally dangerous as it can easily and quickly lead to an unconstrained positive feedback loop. Imagine gas in solution in magma, which is relatively stable. If that gas begins to escape and rise in the Earth’s subsurface through magma, the gas will subsequently reduce the overlying pressure of the magma below it. That in turn allows for more gas to come out of solution and rise in the magma column. In an instant, you can have a runaway situation whereby decompressed gas allows for more decompression and an eventual blowout. This is not dissimilar to some situations seen during oil and gas well blowouts.
The basic problem is that at some point, the magma starts to de-gas and this can start unloading the magma below it that can cause it to degas, repeat positive feedback until lava is being ejected all over the place and and massive unweighting of the magma chamber can cause incredibly explosive eruption. Adding water to rock can also change the temperature at which it melts, so just exactly where water and steam are spreading can cause rock to soften, melt, and thin.
First the “money quote”, then we’ll come back for the context.
Here we use the results of physical and volatile saturation models to demonstrate that magmatic volatiles released by decompressing magmas at a critical degassing pressure (CDP) can drive volcanic unrest towards a critical state. We show that, at the CDP, the abrupt and voluminous release of H2O-rich magmatic gases can heat hydrothermal fluids and rocks, triggering an accelerating deformation that can ultimately culminate in rock failure and eruption. We propose that magma could be approaching the CDP at Campi Flegrei, a volcano in the metropolitan area of Naples, one of the most densely inhabited areas in the world, and where accelerating deformation and heating are currently being observed.
So likely to blow “soon” (in geologic time), but how big still an unknown. Could be little and just destroy the local cities, or could be a VIE 7 event.
The context from the article:
Magmas near the critical degassing pressure drive volcanic unrest towards a critical state
Giovanni Chiodini, Antonio Paonita, Alessandro Aiuppa, Antonio Costa, Stefano Caliro, Prospero De Martino, Valerio Acocella & Jean Vandemeulebrouck
Nature Communications volume 7, Article number: 13712 (2016)
17 March 2016
27 October 2016
20 December 2016
During the reawaking of a volcano, magmas migrating through the shallow crust have to pass through hydrothermal fluids and rocks. The resulting magma–hydrothermal interactions are still poorly understood, which impairs the ability to interpret volcano monitoring signals and perform hazard assessments. Here we use the results of physical and volatile saturation models to demonstrate that magmatic volatiles released by decompressing magmas at a critical degassing pressure (CDP) can drive volcanic unrest towards a critical state. We show that, at the CDP, the abrupt and voluminous release of H2O-rich magmatic gases can heat hydrothermal fluids and rocks, triggering an accelerating deformation that can ultimately culminate in rock failure and eruption. We propose that magma could be approaching the CDP at Campi Flegrei, a volcano in the metropolitan area of Naples, one of the most densely inhabited areas in the world, and where accelerating deformation and heating are currently being observed.
Volcanic eruptions 1,2 are the surface manifestations of the final stages of crustal emplacement of mantle-sourced magmas. Understanding the transition of a volcano from quiescence to eruption is relatively straightforward at the frequently active mafic volcanoes, where the rates of magma ascent and the separation of magmatic volatiles drive pressurization of the magmatic systems and finally eruption 3,4,5,6,7. In contrast, interpreting volcanic unrest is difficult at silicic volcanoes, since they commonly develop pervasive hydrothermal systems during their long repose periods 8,9. The complex magma–hydrothermal interactions that result as magma finally makes its way to the surface during the reawaking of a volcano will modulate the physical and chemical signals recorded at the surface 10,11,12,13,14, and determine whether the magma will ultimately erupt 15
Such magma–hydrothermal interactions are particularly complex and unpredictable at active calderas, where the hydrothermal circulation is particularly intense at the subsurface due to major structural control16,17. This is especially true for Campi Flegrei caldera (CFc), a long-lived resurgent caldera in the metropolitan area of Naples that was formed by the 39-ka Campanian Ignimbrite supereruption, which was the largest in Europe during the past 200 ka (ref. 18). Since the 1950s, CFc has been showing clear signs of potential reawaking, as indicated by frequent episodes of ground uplift (with a total of >3 m of permanent cumulative inflation at the caldera centre19), shallow seismicity20, and a visible increase in hydrothermal degassing14. After a period of major unrest in 1983–1984 characterized by thousands of earthquakes and a rapid uplift (∼1.8 m over 2 years19), CFc subsided until 2005, when a new inflation started, resulting in a minor (∼0.4 m over 10 years) but temporally accelerating uplift. The involvement of magma as a causal factor of the current CFc unrest is strongly supported by the composition of volcanic gas21 and deformation changes 22. However, it is not clear whether this unrest will culminate in an eruption and, if it does, over what timescale this will occur. The presence of more than half a million people living in the proximity of the caldera makes this situation particularly challenging for local authorities and other decision-makers, and highlights the urgency of obtaining a better understanding of interactions between the magma driving the unrest and its overlying hydrothermal system.
While it is universally accepted that the injection of new magma is a common mechanism that drives hydrothermal systems towards the critical state 23,24, the mechanisms and timescales of magma–hydrothermal interactions during unrest remain poorly understood and difficult to forecast16. One key aspect that has received little attention is the role that magmatic gases may play in heating the hydrothermal system, and ultimately in driving the unrest.
The present study linked magma degassing at depth with the resulting perturbation in the overlying hydrothermal system. Here we initially use the results of volatile saturation25 models to demonstrate that decompressing magmas can reach a critical condition, which we refer as a critical degassing pressure (CDP), at which their ability to release water and convectively transport heat is increased by a least an order of magnitude. We then use physical models26 to show that magmatic volatiles released at the CDP, when injected into an overlying hydrothermal system, lead to extensive heating and expansion, and cause temporally accelerating ground deformation. Finally, we examine ground deformation time series from CFc and some other restless calderas, which identifies consistent accelerating ground uplift trends that are reminiscent of those predicted by our model. We conclude that magmas at the CDP can be recurrent causal factors in driving volcanic unrest towards a critical state; that is, a state near a bifurcation at which the evolution of the system can either culminate in an eruption or change trend and cool down 27.
The major thrust of that paper was that magma injections can cause water / steam motion that causes more magma motion. But does not water also migrate into the rock during times of low magma intrusion? Would not there be water soaking in, downward, THEN magma moving up stimulating the rest of the process? This would imply the water introgression could also have large effect.
So here we have that volcanoes are sensitive to the water and steam in their rocks, that a big eruption can cause weather / climate changes, and thus changes of precipitation and ground water (that could, then, help other volcanoes along).
Then we have on a separate track that solar changes can shift UV levels that change atmospheric height, cause a more “loopy” meridional jet stream, shift precipitation levels and locations, that would also change ground water and eventually shift some volcano dynamics.
Might it just be that this water cycle / weather cycle / volcanic cycle interaction is why we have cycles of volcanoes in sync with cycles of climate change? It isn’t the volcanoes making it cold, so much as it is the precipitation tickling the volcanoes that cause more cold and precipitation changes. Maybe.
From that same article:
The critical degassing pressure during magma decompression
The decompression of fresh magma results in the selective release of dissolved volatiles depending on their solubilities28. This means that while barely soluble CO2 dominates deep degassing 3,29,30, more-soluble H2O prevails at shallower depths31. Given this selective release of volatiles from magma and the different capacities of these two species to carry thermal energy, the pattern of heat transfer to overlying rocks and hydrothermal systems will be complex and will vary as the unrest progresses.
Gee, CO2 in large amounts at depth, and degassing…
Water at shallower depths. So how does that water get there? I think this part of the process needs more attention.
They then go on to discuss the variation of magma viscosity and heating with CO2 vs H2O. Then get to Campi Flegrei again:
The case of Campi Flegrei caldera
Of the several quiescent calderas worldwide, CFc has recently shown among the clearest signs of unrest. At CFc, several ktons of hydrothermal fluids are emitted daily by the Solfatara-Pisciarelli fumarolic field40 (Fig. 3a,b). Stable isotopes of fumarolic steam concur to indicate that such fluids are, at least partially, sourced by magma degassing 50.
The large variations in the fumarole emissions of N2–He–CO2–Ar (ref. 21), including the 25-year-long decreasing trend of the N2/He fumarole ratio (Fig. 3c), fully support the idea that a primitive magma degassing in open-system conditions at increasingly lower pressures is sustaining the unrest. A particularly important observation is that the ground deflation and N2/He gas ratios followed exponential-like trends from 1985 to 2005, with very similar characteristic times, implying common source processes14. The presence of magma depressurization is also supported by modelling of the ground uplift in 2012–2013, which has been interpreted as the effect of a magma intrusion at a depth of 3 km (ref. 22). At the same time, a generalized heating up of the CFc hydrothermal system is indicated by the 15-year-long exponential increase in CO emissions from the fumaroles (Fig. 3d); note that CO is the fumarole gas most sensitive to temperature changes 51.
Based on these observations, we argue that the CFc magmatic system may be approaching the CDP; that is, that depressurizing magma may release fluids progressively richer in H2O so as to affect the thermal structure of the hydrothermal system. We tested this hypothesis by using TOUGH2 (ref. 26; see Methods) to model the injection of magmatic fluids (IMF) into a hydrothermal system under physical conditions appropriate for CFc13 (Fig. 4).
In other words: Oh Dear, that’s gonna leave a mark, and likely soon.
(In geologic time scales).