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Keynote by David Pyle at #VICS2019: many volcanic eruptions are explicable, but not predictable.
Andrew Schurer #VICS2019: are we sure that the Tambora eruption caused the 1816 “year without a summer”? Not sure, and changes in circulation *can* produce similar conditions. But Tambora-like eruptions make the cold summer in Western Europe about 10-100 times more likely.
Alan Robock #VICS2019: summer of 1783 was quite hot in Western Europe, despite the huge Laki eruption. Basically, natural variability leading to a hot summer overwhelmed whatever cooling effect Laki would have produced.
Katrin Kleemann #VICS2019: Laki killed about 1/5th of the population of Iceland in 1783/84. But news traveled slowly and mainland Europe provided many speculations about what might have caused the weird mists. It took 100 years and Krakatau to begin understanding impacts of Laki.
Heli Huhtamaa #VICS2019: Court and taxation records show ~ 17th c eruptions associated with spikes in crop failures, farm abandonment, and population loss in Swedish empire. Plus: increase in witchcraft death sentences two years after eruptions.
Ernesto Tejedor #VICS2019: Paleo Hydrodynamics Data Assimilation (PHYDA) shows that over past millennium, eruptions > Pinatubo led to DJF cooling for ~ 5 years in high northern latitudes and warming over central Asia at years 4 & 5. PDSI response more heterogeneous.
Lea Schneider #VICS2019: Maximum increases in tree-ring growth in monsoonal Asia are associated with higher meridional temperature gradients and wetter conditions (sometimes possibly forced by northern hemisphere eruptions).
Stephen Pow #VICS2019: Samalas eruption in 1257 AD might have triggered 1258/9 cholera outbreak and collapse of the Mongol empire.
Martin Bauch #VICS2019: Is the 1257 AD Samalas eruption misdated? Maybe. Lots of documentary evidence for eruption-like impacts in 1256.
Adam Bierstedt #VICS2019: Icelandic sagas are not unbiased recorders of possible impacts of eruptions on society. They were written by and for the elite, who would have been less impacted by Samalas. Also incentives existed to minimize recording of impacts.
Karen Holmberg #VICS2019: 2008 Chaiten eruption was a disaster at the time. Now, a decade later, it's led to a stimulation of tourism and cultural events, discovery of new cultural resources, and new infrastructure.
Franck Lavigne #VICS2019: documentary evidence suggests that Samalas eruption might have produced a pumice raft large enough to link Lombok to nearby island.
Kirstin Krüger #VICS2019: 6th century AD climate deterioration seems to have led to increased use of pigs as food source. Great overview of new VIKINGS project ... now hiring for a postdoc and PhD (both for four years!). mn.uio.no/geo/english/pe…
Stefan Grab #VICS2019: after hearing scads of talks on northern processes, "there is another part of the planet...called the southern hemisphere". Based on documentary, instrumental, and model evidence, looks like *all* 3-4 yr cold periods in S Africa follow volcanic eruptions.
@thirstygecko #VICS2019: massive effort to provide multi-million-member ensemble of northern hemisphere temperature reconstructions. Peak volcanic cooling ~ 0.3-0.4 C, tailing off over a decade.
Amazing venue for the conference dinner at #VICS2019. 
Josh Bostic #VICS2019: intra-ring d13C and d18O allows calculation of seasonal temperatures and precipitation.
Kevin Anchukaitis (for Rob Dull) #VICS2019: Multiple lines of evidence show that the 540 CE eruption was Ilopango, El Salvador.
Kees Nooren #VICS2019: is there another source of the 540 AD eruption? El Chichon is a possibility – not far from Ilopango. But age uncertainties are still +/- 10 years. Temporal association with disruptions to Mayan society.
Rasmus Brandt #VICS2019: Byzantine records document a year-long haze associated with the 536/540 events. Agriculture, pastoralism, and famines arose as possible consequence of climate deterioration. Contemporaneous with outbreaks of plague.
Gill Plunkett #VICS2019: 79 AD tephra layer is not from Vesuvius. Tephra looks like Aniakchak (Alaska) ... but no known eruption. Perhaps a small eruption could have made it to Greenland ice cores? Possible. But most likely source is Mexico.
Thomas Aubry #VICS2019: new box model for vertical/horizontal variation in volcanic forcing. Relative to default approach for stratospheric aerosol optical depth … sometimes no differences, sometimes huge differences. Low elev, high lat eruptions have esp large uncertainty.
Lauren Marshall #VICS2019: translating ice core sulfate record to radiative forcing is, ahem, subject to a wide variety of uncertainties. Statistical emulator shows that uncertainty can be ~ 300 MJ/m2 (i.e. ~ 2x Pinatubo!). Great online tool. see.leeds.ac.uk/see-research/i…
Dallas Abbott #VICS2019: you can get time of maximum AOD just from ice core sulfate. Involves removing seasonal and pollution signals. Varies by location/eruption, but max AOD is ~ 2-11 months after eruption.
Andrea Burke #2019: If D33S & d34S in sync over eruption = large tropical eruption reaching the upper stratosphere. Allows diagnosis of tropical vs. extratropical & % of deposited S that reached the strat. Forcing reduction for large extratropical eruptions AND strong cooling?
Anja Schmidt #VICS2019: Recent work suggests 946 CE Changbaishan eruption produced plume > 25 km high w/ 90 Tg SO2 (50% > Tambora and 2x RF of Pinatubo). But low sulfate deposition & no clear cooling/societal impacts. Instead, model emulator suggests max emission of < 22 Tg SO2.
Keynote by Siwan Davies #VICS2019: tephra and crypto/microtephra has huge potential for volcanic dating and source identification. Needs improvements on: sampling strategy, detection method, geochemical analysis, source characterization, and lags between tephra and aerosol chem.
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