 Good evening everybody, my name is Campbell Forrest and I'm a member of Council of the Society. Although tempered a bit by the fact that we can't all be together in a live meeting, it's a real pleasure to chair this evening's meeting with Tamsen Mather. Tamsen, of course, was the first casualty of the pandemic in terms of speaking to the Royal Phil, at least. And she's, we're extremely grateful to her agreeing to do the first presentation of this new season. Tamsen is Professor of Earth Sciences at the University of Oxford, and her main research interests lie in the field of volcanoes and volcanic behaviour, as natural hazards, as a key planetary scale process throughout geological time, vital for maintaining habitability, and as natural resources. She is an esteemed academic, highly successful in attracting research funding, and has many publications. Her advice has been sought by governments and policymakers in the UK and internationally. She has received numerous honours and awards, one of the most recent, being the Royal Society Rosalind Franklin Award. And I'd like to highlight her extensive outreach work, including with the BBC. This has included improving the accessibility of science to children, and in promoting the role of women in science. Now, in January of this year, the Society, by dint of chance, or as we prefer to think, superb planning, arranged a presentation by Professor Wendy Barclay of Imperial College, and the subject, The Next Influenza Epidemic. Then on the 3rd of March, an influential book by the moral philosopher Toby Ord was published. It is called The Precipice, and it examines existential risk and the future of humanity. He reviews many types of risk, and calculates that the risk of existential catastrophe via naturally arising pandemics is of the same order as via super volcanic eruption. We sincerely hope, Tamsen, that the Society's predictive track record does not extend quite so rapidly to the subject of this evening's presentation, which is volcanoes from fuming vents to extinction events. Over to you, Tamsen. Thank you very much, Campbell, and thank you very much for that introduction. I'm just going to move now to share my screen and get into presentation mode. I hope that that looks okay. So I'm going to talk today about volcanoes from fuming vents to extinction events. I'm really, really disappointed not to be with you up in Glasgow this evening. Obviously, lots and lots of disappointment around, but I was really, really looking forward to the trip and to meet you all and to having the interactions that really we can only have face to face. But obviously we're all getting used to this sort of new normal and this new Zoom environment. And I believe I'm the first speaker in your society's long and illustrious history to speak remotely or to speak over something such as Zoom. So I felt like I ought to sort of start off by marking this. So I thought I'd share with you a little story from early in lockdown when I first started trying to use Zoom. And my first attempt to use a virtual background in Zoom, which is actually the same virtual background that I have on display tonight, which is from the Etna 2001 eruption. But anyway, this was my first attempt to use a virtual background in Zoom. And I thought it was quite amusing. It was on a call to other volcanologists that everyone was quite taken with what I've become. So I put this up on Twitter and just said, fair to say I've not entirely mastered the virtual background feature on Zoom. I got some quite pleasing results. One of my colleagues in the States sort of said she saw a Zoom meeting with a being of unspeakable power, which is the first time I have been referred to like that in a meeting. So I thought that was a reasonable result. Someone else thought maybe I was one of the X men and Zoom was able to spot mutant genes. And then another of my colleagues thought she couldn't think of a better deity to teach volcanology. I also got a few comparisons with various monsters. This is a monster from a demon from the TV series The Good Place. The lava monster from the Disney film Moana. And then of course Lord of the Rings and there's Gandalf saying, go back to the shadows you shall not pass. I'm slightly more disappointed it was the response from my colleague in Durham Colin McPherson. And this was his first thought I think this is the least said about that the better. So I have now I'm pleased to say if lockdown has given us nothing else I have mastered the virtual background feature on Zoom so you know there's a there's a silver lining in every cloud, I guess. So back to this this picture here and this is actually one of my favorite pictures of volcanoes although there are lots of favorite pictures. And this is of course from the AFAC Yerka eruption in 2010. One thing I do like to start with this is often brings brings to people sitting in the United Kingdom, the relevance of volcanology for their everyday lives. So I can't kind of cast my eye around the the room and ask for a share of hands but I would put money on the fact that at least one person in this call has was had travel plans affected by this 2010 eruption. It's a little trivial now with the the general lockdown of travel that we're experiencing right now. It's also, it's also a very interesting eruption in terms of where it's located. So it's a hazard a hazardous eruption the reason all those planes were grounded is because of the hazard from this this ash cloud coming over airspace and potentially planes dropping out of the sky. But actually the local in the local Icelandic area where it was based it wasn't very hazardous at all it was quite a low key, small, moderate eruption. But the fact that it's based in Iceland also gives me chance to sort of speak about volcanoes in a different way so volcanoes are hazards, but actually Iceland's a country that gets a very significant percentage of its power from geothermal power which is related with the volcanism that has built its country as well so volcanoes have this sort of already had this sort of dual personality embedded in them they're both hazards but also resources that we use as humans. And the other aspect of volcanology that really really deep deeply deeply fascinates me is actually what Campbell was saying in terms of their role as a planetary scale process that basically their role in forming the planet that we see around us today. And ultimately, I guess, ourselves as human beings and our ability to sort of sit here and wonder about volcanoes and other other parts of the wonderful world that we inhabit. I guess in this picture this is symbolized by this bolt of volcanic lightning, it's not a, it's no coincidence, the lightning is there is actually generated from some of the processes going on in the plume. The bolt of volcanic lightning just reminds me to say about the interaction because it's actually one of the candidates for forming some of the molecules crucial for life to actually evolve on the planet is this sort of this this these high temperatures that you get in this in this in these bolts of volcanic lightning. So really this is what fascinates me about volcanoes is they have all these different facets to them and the science around all these different facets in is really really very interesting. And what I'm really going to focus on today is actually that kind of one of their roles in the geological timescale. So what I want to sort of convince you today is that by sitting in, in making measurements in a the fumes from a volcanic event. I can actually get insights into some of the most fundamental events back in back in geological history, obviously namely extinction events. So this is kind of being a, for some reason it's not wanting to, up there we go. This has been sort of something of a personal journey for me so I started my PhD back in 2001. And this is me on my very first field trip ever to Messiah volcano in Nicaragua. In 2001 so here I am with all my kit here measuring essentially some of the fumes coming out of the of the volcano here to understand what's going on. And you might like look at this picture and I think it looks pretty terrifying you know I've got an enormous gaping crater in the background here with gas, hazy gas seeping out of it. I personally find this image quite terrifying these days for completely different reasons which is which is basically how young I look in this image now. It really reminds me of the passing of human time not just geological time. I'm making my measurements. You can see here I'm hard at work sometimes we have to leave the measurements running for quite a long time and in the sun the heat and your gas mask you can kind of doze off for a bit and have a rest. And this is what I was peering in at when I was looking over, making my measurements into the volcano and you can see this gas coming out of here. And I guess one of the reasons that I was studying this gas here was about the hazard of the volcano trying to understand what's going on deep inside its guts if you like. But actually another thing that was or which was which was very much the focus of my PhD was also looking outwards from the volcano and looking at this this gas cloud coming out here and thinking about how it interacted with with the local environment. And of course that the global environment as well. And that's what it looked like back in 2001, but Missile volcano is changing all the time so I just want to show you a little video clip from the last time I was there in 2017. Just to give you an idea of what's actually going on down that vent. So this is the first time that that I've seen this. So you can see how energetic the magma is that was hidden from us in 2001. And you see these bursts and the slugs of gas coming out of the out of the magma there you can see a few bursting up there very dynamic situation almost like a kind of fiery blowhole looking down to the sea during during a storm. So this this gas is being brought out from inside our planet through this this conduit through this volcano, and then drifting off out into the environment. So the other thing that was the first year of my PhD so I started making measurements and volcanic events and thinking about what was coming out of the volcanoes and how to understand them better. But actually in the last year of my PhD I attended a lecture in Cambridge, one of the Darwin lectures. And, and for the first time I saw this very influential graph that really kind of embedded in my mind. And this was a talk given by a French scientist called Vance Courtier from from IP GP the in Paris and basically his talk was was all about catastrophes in the evolution of earth and life. And, namely about the connection between these catastrophes and volcanism. So what this plot that he put up in that in that talk has here is it has on this axis this is a geological timescale going from zero so that's present day to do 300 million years on both axes. And what he was plotting here were the ages of extinction events in the in the earth record so these are these these different extinction events here, named along in this section here, against the age of volcanic traps. And we're going to talk, I'm going to talk a bit more in this lecture really about what both these, both these terms mean, but just to pick out one that you might have, you're most likely to have heard of. So this this end cretaceous event here is the one that's the most famous for people. Especially because it's the, it's one of the most it's the most recent one but also because of the demise of the dinosaurs. This this this blob on a graph here basically is is indicating where the where the dinosaurs went extinct. Of course, you can find some great, great cartoons on the internet. There's a lot of debate to this is still a lot of debate about what killed dinosaurs. And you might have heard the kind of was it that wasn't volcanoes or was it an asteroid impact. So I put this, this, this asteroid emoji type thing here. And if you look on the internet you can find sort of cartoons like hey Arthur check it out shooting style that's a sure sign sure sign of good, good luck my friend, because it turned out not to be so much good luck for the dinosaurs. Unfortunately for them probably fortunately for us. But, but you can also find various suggestions also that actually the demise of the dinosaurs was intimately linked with this this these traps here, the, the Deccan traps. This this debate is still is still very current today. Let's look a little bit through what this type of volcanism what this traps this volcanic traps type of volcanism is like. So we often call this large igneous provinces I'm going to kind of in a second sort of site that within the types of volcanic activity that you might be more accustomed to more used to. There's really balkanism on a scale that we have not seen in the historical record, the most recent example of this is the Columbia River flood vessels and that was 17 million years ago so we don't we don't have a, we don't we have no sort of historical in on how to understand this. If you go and look at these, these are these traps basically they cover absolutely enormous areas, this is the Deccan traps this is the subcontinent of India here. And this is the area just covered by the, the sub area not the submarine the land based part of the Deccan traps because it broken up a little bit more in terms of how it fits in with with with India just here and there's Mumbai in order to orientate you. If you go look at these in the field they're just there pile upon pile upon pile of lava flow. And just to give you a sense of scale this this wonderful image here unfortunately of the Deccan doesn't have a scale in it so I put this Columbia River there's a bus a coach there, and a kind of barn as well just to give you a sense of the scale. So layer upon layer and layer upon layer of lava flow has built up over time to make these massive, massive types of scenery and topography. And if you look at them they say they have some sort of shared characteristics but just to take the Deccan for example. The Deccan traps basically put out about a half a million cubic kilometers of lava onto the surface of our planet. So that's a really difficult thing to get your your head around but just to give you an idea of what a cubic kilometer of lava would look like I did a quick And I think if I'm correct a cubic kilometer just one cubic kilometer of lava would actually bury the whole of Glasgow under six meters of lava. On the same the same volume of lava would actually bury all of Greater London London under 60 centimeters of of of lava, or the whole of Wales which which which apparently are sometimes used as the unit of catastrophe. The five centimeters depth of lava. So this gives you a scale of the volumes that we're talking about. And they also put enormous quantities of volcanic gases so come back to us off without excited what it means later. And most of this activity is focused within about one million years which sounds like it sounds like a very long time but this is over a sort of geological time scale. So these these are enormous episodes these are enormous elevated episodes in terms of how much how much volcanism is going on on our planet during these sort of one one million year one million year episodes. And the Deccan is not alone so here is the Deccan traps here again so you can see that that footprint on India and then the submarine footprint as well. But actually the surface of our planet is kind of peppered with these the evidence of this is possible kind of activity. So you can see here the red ones are the other ones that came out on the continent so they they they were sub aerial they they were into into the into the atmosphere. And then you've also got these enormous oceanic plateaus that actually erupted under the waves. And I just wanted to draw your attention to a few of them here because I'm going to come back to them. So we've got the Siberian traps about 250 million years ago covering the enormous area of northern northern Russia. And if you ever get the chance on it seems like a kind of pipe dream at the moment but I want I remember vividly flying from London to Tokyo on a day flight once and getting a window seat. And just staring out for what felt like hours at this the amazing kind of trap topography these layers of lava flows as I flew over Siberia. Another one I want to we've talked about the Deccan and another one I want to draw your attention to is this this central Atlantic magnetic province of the camp here which is about 200 million years ago was erupted. It's torn apart so you now find it on three continents together and perhaps that that give you a clue about what the what the arrangement of the continents look like that back in geological time. But it's now found in South America, North America, and northern Africa as well. So these are just some of the examples that we have and I could go on and talk through many of the others. Let's take a second and just orientate ourselves, and I think about how the, how this sort of fits in with different styles of volcanism that we might actually have some some knowledge of. So really volcanism exists on entire spectrum of, of, of kind of of explosivity or size. When I was talking earlier about sitting in the volcanic plume from Messiah volcano, here's another picture of Messiah volcano. That's kind of right down on what I call the everyday volcanism end of the scale. So I think about volcanoes like Messiah, or this is volcano volcano and the Ionian islands are just off Sicily. Volcanoes are pumping out gas and particles into the atmosphere every single day of the year. This if you if you went to Messiah today, it would be doing something very much like this so it doesn't really make the news. It's just part of the background activity and actually it's part of the background activity that kind of maintains our atmosphere, if you like, rather than rather than perturbing it. Let's step it up a bit. We go to these. So this is Hawaii now this is the 2018 activity of fissures on Hawaii. So you see that you can have volcanoes that go through periods of much heightened activity even though Hawaii was erupting since the 1980s. Actually it's it's quiet now after this episode, but you can have fluctuating everyday activity as well. So you can see that this is Etna you might recognize this as this is my current backdrop at the volcano, which again is is pumping out gas and everyday activity but then also has these these sporadic eruptions like this one here in 2001. This is much larger types of volcanic activity. So this is Mount St Helens eruption in 1980 which scattered ash all over North America. And these sorts of eruptions here are like, they're sporadic so you might have Mount St Helens has been quiet now for years and years and years. But every one or 200 years you'll have one of these much bigger eruptions that puts out lots of material, but that is quiet for a long period of time. And then we get into these scales of activity that we haven't seen in historical time so I've talked about this is the Columbia River basalts from 17 million years ago. But there's also as Campbell already alluded to super eruptions. So this is the footprint of Toba volcano in Indonesia so it's about 100 meters kilometers across just to give you a sense of scale. That's erupted about 75,000 years ago. This is a sort of nested cold era systems so different footprints there. So we go these are these are very very rare events on this end of the scale but when they happen they they really perturbed the planet in a really big way. One of the things I'm very interested to do really is to understand Vulcan the impacts of volcanism on our planet right across this scale. So how we time average and how we deal with kind of short term versus long term effects of all these different types of activity. So how do volcanoes have what do they what do they bring to the surface what do they how do they change the environment how do they impact on our planet. So some of the things might be quite obvious we already talked about lava flows for examples they're putting out lava flows down the sides of the volcano or over the scale of a province in the case of large igneous provinces. But those are those are quite localized effects. There's also different types of flows you can get pyroclastic flows that some of you might have heard of. Explosive volcanism also puts our ash we talked about ash in the I fight the earth's eruption so broken up bits of rock. And these can be blown away by the winds and really blown quite a long way away from the volcano so you remember the ash coming out of the I fight the earth in Iceland. This is scattering over much of the northern hemisphere depending on the wind direction. There's a little cartoon here these are our ash particles being put out, but volcanoes also emit a whole cocktail of different gases and some of these gases are quite reactive in in this environment. So the dominant gas that comes out and most volcanic preems is actually water and I guess this shouldn't be too much for surprise given how much water there is on our planet in general. Although a lot comes out of volcanoes our atmosphere is actually quite used to having very variable amounts of water in it. I don't know what the weather's been like in Glasgow recently but certainly over the weekend in Oxford we have an awful lot of water in our atmosphere. But the atmosphere is used to having lots of water and very very changeable amounts of it. The second most common gas is often carbon dioxide. And obviously that can have well rehearsed effects in terms of the greenhouse emissions acidification of the oceans and things like that. Then we get to the sulfur gases so we get to sulfur dioxide and hydrogen sulfide which tend to be the the next most dominant. So sulfur dioxide smells a little bit like burnt matches and hydrogen sulfide is your kind of classic volcanic rotten egg smell. And I was giving quite a graphic description these ones on the BBC World Service and they kind of dubbed me the connoisseur of volcanic gases, which was, which was, which was maybe I should get some business cards printed up with that or something. But anyway you have these these two different gases that sulfur can exist on depending on other parts of the chemistry. And then we have the acidic halogen gases so we've got hydrogen chloride hydrogen fluoride and small amounts of hydrogen bromide. And they can have effects such as acid rain, but also especially with hydrogen bromide here they can destroy ozone and things like that so there's a whole different manner in which these gases can interact with the environment. And these gases interact with with aqueous droplets they can interact with the ash but they can also interact with little water droplets in the in the volcano and actually a lot of these water droplets will be formed from sulfuric acid, which is a reaction product of the sulfur gases in the volcanic plume will come back to the importance of that in a minute. The really interesting thing about this cocktail, which I should mention as well I'm going to come back to can also contain contain trace metals so some metallic species in there I mean really the volcanoes are kind of chucking out the periodic table if you like. One of the interesting things is that this cocktail it can kind of vary between different volcanoes it can vary between different volcanoes at different times. In fact you can get different chemistry going on in plumes, even from the same volcano at the same time. So just to illustrate this this is this image again from Etna in 2001. And here we have a really ash rich plume from the fissure eruption going on just downslope from the summit here so you can see this dark ashy plume. And then here from the northeast crater, we have actually very much business as usual we have a everyday digassing going on and we have very steam rich plume with some of this sulfuric acid aerosol giving it the sort of characteristics like the bluey white appearance just here. And then at the southeast crater here we have this sort of mixture this lighter ash so it's got some ash in it but not as much as that but more than that. It's almost like we've kind of got a blending of different volcanic plumes there and they each had their slightly different chemistry. So a lot of our understanding of volcanoes comes from observations that we can make in the present day and then we can use the rock record to kind of scale those up and to understand how they might have operated in the past and a really key eruption was this eruption here, the Mount Pinatuba eruption in June 1991. And this is actually a picture this is a picture taken a couple of days before the the climax the the main eruption itself, but you can see it's already looking pretty fierce and even at this stage. And it basically was a massive eruption column it punched really high up into the atmosphere so it got a column up to about 35 kilometers up into up into our atmosphere. Just relatively small on the scale of what we were talking about earlier in terms of large, large igneous provinces just five cubic kilometers of lava or magma put out there, but 20 million tons of sulfur dioxide punched up into our stratosphere. So we caused a roughly a 100 year event so that means that every 100 years we'd expect that on average to be one eruption of this sort of size all around the planet. What was really critical about Pinatuba was it was the first eruption of its size that we'd had in the in the satellite era on the space era really. So for the first time we were really able to see what was going on with our planet we knew we knew that volcanoes could have global effects from eruptions like Tambora and Krakatoa going back in history. But this time we had eyes in the sky, I could really understand we could actually had data from actual human observations. So these are some images taken from the space shuttle. So the surface of the earth is down here and then we've got the darkness of space out there and you can see some cloud the shapes of clouds here. So this was taken in 1984 since this is the so-called little clean atmosphere and you can see there's a great great general gradation out into space. And this was taken August 1991. So just after the eruption in June, what you can see is this weird optical effect up above the clouds. There's a double layer here, which is caused by the volcanic emissions sitting in the stratosphere. And we could be a bit more global and also technical in that we can actually use satellites to to understand what was going on. So what we've got what I have here are four images from a satellite, the Sage II instrument looking down on the planet. So this is mapped out mapping out what it can see in the planet. And what this instrument is looking at is something called optical depth. So what this is roughly is how hazy the stratosphere is. So how hazy the atmosphere, the upper atmosphere is. So if you've got cold colours here, it means it's everything's nice and clear. And if you've got hot colours, everything's misty and hazy and foggy and not very clean and see through. So you can see these dark colours just before the eruption. So this is an average of May to April 1991. So these dark colours, nice clear stratosphere that we can see through. Then after the eruption, we've got this this this belt, this belt of haziness that has spread around the around the belly of our planet. So the the eruption is around here in the Philippines. And it's actually already spread all the way east west around the equator. It was quite important that it was an equatorial eruption because that meant it could get into both hemispheres. And then you can see that the haziness starts to spread north and south. And by 1993 you've got this general it's beginning to clean up a bit, but you just got this general haziness around the whole outside of the planet. And what's causing that haziness is actually the sulfur chemistry, the sulfur dioxide has got up into the stratosphere here. And then it's slowly reacted, it's slowly oxidized to form that sulfuric acid aerosol. So there's fine mist if you like of particles. And we know that we know that that particles into affect how visible things are because that's when we get cloudiness when we get the clouds sitting low down on a hilltop or sometimes over a river or something like that we know that things get hazy and we can't see as far and this is basically what's happening in our stratosphere. We're not able to see as far. But it wasn't just an issue for the stratosphere. It wasn't just haziness in the stratosphere had an effect on us down here in the in the lower atmosphere in the troposphere where we live. So this is now a temperature anomaly map from the summer after the penalty of our eruption. So about 12 months afterwards. And what this is is it's taken a kind of time average of about a decade of temperature data. And then looked at how that year was different from from that time average that average of temperature data. And what I'm sure you'll picked out is that it's mainly blue. What we were mainly seeing was that that's that summer of 1992 was actually colder than the previous 10 years. So, on average, there's some quite interesting features which I won't have time to talk about today in terms of this this hotter area over over the Antarctic. But on the whole, it was it was cooler. And the reason for that is that those those little aerosol particles those fine fine little particles sitting up in the stratosphere that are making it hazy. What they're actually doing is they're also reflecting some of the sun's energy back out into space. So you know the way that the clouds can look bright and white if you shine a shine a light on them. Because they're reflecting light energy back back back up at you. So if you've been an alien sitting on the moon was it your Mars and you were looking at the earth. After the pinot tube or the eruption the earth would have gone got just that little bit brighter as it was reflecting more of the sun's energy back out into space and what that meant was that we were cool that things were cooler on a global scale down on the surface of the planet. But this type of volcanism this the pinot tube or sort of type of volcanism. It gives us a lot of insight but it's actually a very different style of volcanism to the sorts of volcanism that we get in large igneous provinces. So you remember I already talked about lava flows being put out onto the planet. So it's much less about these enormous columns punching high up into the stratosphere into the atmosphere. It's actually a lot more like a very, very large scale every day type of volcanism but there's sort of a scaled up version over a massive area happening over a prolonged period of time. So we can get other insights from going and studying these these different types of kind of lower key eruption on the present day planet. So take us back now to Nicaragua and to Messiah volcano in Nicaragua. And this is where I was showed you the images before sitting up at the crater rim there. And you can see this this gas plume that we were looking at last time, coming out of the volcano there and then getting blown off downwind. So you can probably guess it's a photo taken from an Agua airport. And I was actually leaving early in the morning, feeling a little bit grumpy I'd had to get off, get off at about 430 in the morning to to get ready to board my flight and it was also my birthday. So it's really particularly grumpy at the idea of spending most of my birthday that in Miami airport and transit. And the volcano did treat me to this beautiful final view, looking down at it so I'm looking down southwards along the country here, and the plume is blowing off towards Pacific like this. And the thing you'll also notice here so here's the volcano it's not a very tall volcano. We've also got quite a lot of highland downwind of the volcano so actually the closest community to the volcano is this, this village here of El Panama, which is only about two kilometers. You can just see that's roughly where our Panama is is there. And they are, they're regularly fumigated by the volcano so we can start to see the sort of impacts on the environment this type of persistent volcanic activity can have. What you see here is this sort of characteristic yellowy scrubby ground that you get in the area around El Panama so a lot of the Nicaragua countryside is very lush and green. And one of the main cash crops that they grow is is coffee, but they can't grow coffee in this particular area downwind of the volcano you basically this is some of the examples of the sorts of damage that coffee plants can sustain these leaf burns from the acidic acidic gases. So it's a very poor community in any case this is sort of this is one of their houses, but the volcano really adds that in terms of the respiratory health, but also like they can't use nails to hold their roots together because they just rust through it and they've had to adapt their agriculture so they can no longer, they can no longer grow things like the cash crops like coffee but actually they have found that dragon fruit pineapples survive very, very well in this environment. In fact some some say better in this environment. So you can see there's some impacts of the increased acidity from the volcano on this area. So we can scale it up against the missiles actually not putting out much lava and is a relatively low flux of gas but we can also go and have a look at perhaps the closest analogues to present day largely as type eruptions. And this is another photo I like very much volcanic activities and this is the Holorun eruption in Iceland a little bit easier to save and I thought the year could back in 2014 and 2015. And this put out an enormous amount of sulfur dioxide into the atmosphere, but still was a very much smaller scale than the largest provinces it's only about a cubic kilometer of magma. It's just over a six month period, particularly like this this this amazing photo at the volcano with the northern lights in the background and this this case there is no connection between the two phenomena. But it does make the picture even more spectacular than just the volcano on its own. So we're using subtle using satellites and ground based measurements. So we're using computer models we were able to go and study these emissions from Iceland understand more about the types of environmental processes going on. In terms of this type of eruption that's much more analogous to largely news provinces. So hopefully persuading you some of the reasons we might want to study study present day volcanism to understand the mechanisms that for their effects on the environment. If we go back to this plot again that I showed you already remember we've got this age, these geological time scales on both axes. I want to unpack this a little bit more because actually later on in Vansol Courtier's later works he did change the labeling on this axis here but actually what we have on this this in terms of all these different events here is quite a family of different types of activity. So we've got these, these, these major mass extinction events we've got to the end Cretaceous the end of the dinosaurs and also the end Triassic and the end Permian. But we've also got some different types of event here so we've got minor extinction events, and also environmental change events so we've got a whole whole range of different environmental responses going on to these these different volcanic trap events on on our planet. And I've labeled these major mass extinction events five four and three because actually that that they are three of the big, the big five mass extinction events. And if we home in on just those those big five mass extinction events I've now put the geological this is another version of the geological time scale so we're going from present day to 600 million years ago now so stretch it out a little bit further into geological time. So think about this in a little bit more detail. So the geological timescale is something that kind of quite easily give you vertigo, I find, so the earth is 4.5 billion years old. And just to kind of get an idea for that is if you, you could, if you put your arm out to the side and you imagine your shoulder is is 4.5 billion years ago. So your fingertips are present day. The time that we've been on the planet is just actually if you took a nail file and drew it once across your, your nails that would give you the kind of proportion of the geological timescale that modern humans have been around so we're really the nail dust on this planet. And most, most of us history did not happen without without our involvement. How we're going to interact with it in the future is a different matter. But if you take these big five the interesting thing is you can see that although the duck and traps as I showed you earlier we have this impact of this, this meteorite impact. The other big five, the other four of the other big five mass extinction events basically line up with different types of trap volcanism so we've got the central Atlantic Magnetic Provence, the Siberian traps, and then the valet traps which are also in Siberia. And then we start getting very much very deep into into geological time, and we start to run the risk of basically losing part of the geological record in terms of the seafloor has been subducted, and continental collisions have destroyed other parts as well as of course weathering as well. There used to be something going on which the although there's a lot of argument about the Deccan. There doesn't seem to be the same evidence that we found as yet anyway for asteroids hitting at each of these points there's some there's something going on in terms of a time coincidence. We've actually had this idea of mass extinction for quite a while. I found this one this lovely sort of page in the in an old book which you can actually get online from John Phillips who was who was actually a geologist working at Oxford this is a picture of his statue and the Oxford National History Museum, which is just a stone throw away from from my office when I'm when I'm working there. And this is a page from one of his book, basically, back in 1860, which he generated just from looking at the British geological record we're very lucky in the United Kingdom to have very rich geological record. And then he was able to spot to just by looking at British fossils was able to spot two of these major mass extinction events so there's the end Cretaceous and the end Permian. So he hasn't hasn't hasn't picked up number four, but but he managed to get those two in this very early plot. And it's a wonderful book and it sort of quotes Latin Latin poets in it which we just don't write scientific papers like we used to but so some people wax others Wayne and talks about handing the torch of life from individual to individual. His method of handling the torch of life is a little bit maybe unfortunate in that he seems to have passed away on after having a very hearty dinner at all souls college in Oxford, and then tripping over a carpet and falling down the stairs. So I think this ought to be this is a lesson to us all, but but so rather unfortunately, a long timely demise. Yeah, if we zoom in just have a think about what he was doing there when he was putting that data together in order to understand that mass extinction so if we zoom in here on the end Triassic so this is the time associated with the the central and two province. I just want to draw us in on what the world looked like at that time so you remember I said that now we have deposits in North and South America, and a northern Africa as well. This is because the continents were grouped together in a super continent. It's about 200 million years old. So we have this massive province this massive central Atlantic, magnetic province associated with the opening up of the central Atlantic as well by tectonic forces. And we lost about 76% of all species. So I think that works is in terms of in terms of actually understanding it is when you when you go and look through the strata through the sedimentary record of geology. You go and you can look you can step your way through an extinction event. Basically you by looking at your pre extinction ecosystem which will be recorded in the fossils in the sedimentary rocks. You'll find that you have very few or no fossils during the extinction horizon. And then you start to see a recovery phase afterwards when different, but relatively no diversity of species start coming back. And then the full recovery the post extinction phase when you have a full ecosystem again but it's a different ecosystem to what you had. And you can you can you can go to places you don't have to get on a plane to see some of these amazing rocks and this is just to give you an example this is down in Dorset. Just near lime regis so you just go down to lime regis and onto the beach and walk to your to your right. And you can basically walk through a mass extinction event so you go from these these lighter triassic rocks here up to these these these layered Jurassic rocks above. This is the end triassic mass extinction here. And you can go to these fantastic ammonite pavements just there and that's this sort of richness recovery phase. The way people now find out about it which wasn't open to the early pioneers of this was is actually to drill into the sedimentary sequences and have a look at the biology that we have going in. Because the extinction events themselves are recorded in the in the in the sedimentary rocks and they're recorded by looking for these changes in biology. But the issue is when we're thinking about looking at something like camp volcanism so central Atlantic my magnetic province volcanism. They these, these, these, these lava flows are not recorded in the same columns. We specifically chose the camp because we're quite lucky with that in that sometimes they are so we have more information with this than most of the other extinction events. We've got some columns like this one Newark, Ghana or Fundi marked on this map, where we actually have the basaltic lava flows from the large igneous province, interleaving with the sedimentary record that's telling us about the biology and this is what it looks like in the field so you've got these red sedimentary sequences, and then you can see this massive lava flow through here with some trees for scale on top. You can see it again here's this is in the Fundi basin up and number six up here in in Canada right there. So in the camp stratigraphy we actually do have some of these you can see one, the numbers here 123. There's different lava flows that have been recorded in the sedimentary sequence, but generally to actually build a picture of what's going on all around the province we're going around the planet we're picking up chunks of lava. And then we're looking at the radioactive isotopes the radioactive decay and some of these crystals in each of these chunks of lava, and we're seeing how old they are. We're seeing chunks of rock from distinct places in the planet and trying to match them up with the these these sedimentary records of what's going on with the biology and what's going on with the environment. So these sedimentary records here we've got this this line here this mass extinction event. If we go around the, we go around and we look at all the different parts of Central Atlantic Magnetic province. There's an enormous range of dates in terms of what was going on. And all of these dates have have quite significant error bars on them. So what's quite tricky here is for us to really understand cause and effect. So if we have this horizon here, where we've got the, where we've got the, the extinction event going on. So these these events here where where the dates captured in the lavas that could, for example, be this this flow here which is the Amalal sill. Basically it could be before it was going off or it could be after we're not really sure. And again here with the North mountain basalt up in Fundy. It could be going before the extinction event so it could be causing it but actually there's also equal probability really that most of it was happening afterwards. So we get this very complex picture that's very hard to understand cause to use to understand cause and effect. And this is where the second part of actually sitting in a volcanic plume can help us to understand what's going on in these ancient deposits with these ancient volcano volcanoes. So these are, these are my, this is a picture of me taking samples at the top of Mount Etna. So this is one of the, the Bocca, the mountains of the volcano at the top here. And here I am wearing my, please see where my hard hat gas mask and the sun hat just to be fully protected from the extremes of the environment. Actually I went to give a talk at the Lapworth Museum in Birmingham recently and to advertise their talk, they use this picture which I think is probably from the CVS or Etna from their collection. So, so I'm now slightly intrigued by the idea of trying to get in this outfit and go on field work which strikes me as extremely impractical, but I thought it was quite a funny photo that they used to advertise my talk. And what I'm doing here on the top of Etna and I'll show you a little bit more about the second is actually measuring volcanic mercury. So mercury is an element. It is the most, the most volatile the most of all the metal elements in the periodic table. It's the only metal that is liquid room temperature. Some of you like me might have been at school where we used to use mercury thermometers and physics experiments so I don't know if any of you remember when you broke one of those and it's a little ball silver balls would scatter off. And you should have to get the sulfide kit out to sort it out. It's a toxic with the reason we were studying it from volcanoes it's a toxic metal and it bio accumulates in the food chain. So there's advice for example pregnant women are suggest our advice not to eat too much tuna fish. And the reason for that is because mercury can accumulate in tuna up the food chain. And this is a volatile metal what I mean by that is that a significant proportion of it will exist as a gas. So there's actually mercury in the background air all around us if you take a nice, nice deep breath of air into your lungs right now. Up in Glasgow, as an Oxford a couple of nanograms of mercury in that in that breath that we've just taken. Volcanoes are a major source of mercury so actually what when I started off during my PhD doing was to answer that question is about how much mercury comes out of volcanoes, but also about how it comes out. So mercury mainly because volcano is very hot mercury mainly comes out as a gas. And what that means is it doesn't fall out of the atmosphere with the ash and the particles it tends to be really widely dispersed in the atmosphere. So these things make it very interesting in terms of whether we can use it as a fingerprint in the sedimentary record for these, for these large igneous provinces. So I just wanted to show you a few photos of from the fields. This is sort of a little mini insight into one of our field trips going out Mount Etna. This is the view from this is the view from one of the places that we've stayed. So, looking up you can see the top of the volcano lots of lovely volcanic gas to go and go and sample. So you drive up to the top of the road so the drive the that's the top of the road so it ends about there. And you drive up my colleague Sandra from Palermo University, there I am, pack all the equipment into rock sucks. Take your gas masks and helmets and there we are truck trekking off up into the volcanic haze up at the top of the volcano. So I'm gonna show sort of gas carrying a an instrument there. Some of sometimes the roads a little bit rocky and tricky here we are kind of skirting along the edge of the Bocca Nova on the summit there's one of the guides up in front. And here we are doing doing sampling on the crater rim. Again we're setting up instruments to run here we're trying to change over the filters on an instrument in a clean manner up at the top of the volcano, which is very very tricky. tricky so I can't really work out, it's quite windy in this shot. Here's Andrew and Sandra having a bit of a rest while the sampler's run and sometimes it's very very nice on the top of it, knowing you can have a rest and other times it's absolutely miserable and you can see here the clouds come down, the hail's coming in, that's probably sleeting or snowing and we've got to stay there until the samples are finished so we're all sort of hunkered down at the top there and feeling relatively sorry for ourselves. And this is what these are the sorts of measurements we're doing, we're basically measuring different types of mercury metal coming out of the volcanoes, just we've got some things here, we've got little gold traps that we've pumped bits of the plume, some of the plume through, it's just attached to a pump there and it collects the mercury on these little gold beads and then we have other traps that we trap trap it in the particle phase that in those volcanic particles there and then we're also looking at some of the other, this is something called a glass denuda which we used to look at some of the other types of mercury chemistry coming out. This is really one of the least practical pieces of equipment to take up a volcano ever, you can see this sort of delicate glass tube and several of them have got broken which is very frustrating when you spend just spent many hours trying to get a really good sample and we can use real-time instruments as well, this is a special spectrometer that we can use to actually find out in real time every second how much mercury is coming out of the volcano. So how can we use this then to answer some of those questions about cause and effect that we want to answer in the geological record? So the thing we can do is that we've got this massive province of volcanism going off so we're back at the Central Atlantic Magnetic Province here 200 years million years ago and you can see that there could be activity going on all the way around this province or it could be going off here and not there or there and not here so we don't know when most of the volcanism was happening and we don't know when that peak in volcanism relates to the extinction event itself and you remember that's because of those big chunky error bars on the rock measurements on the dating of the rocks themselves. But what we can actually do now is to run the chemistry of the sediments so we can look at the very sediments that record the changes in biology so the very sediments that record things like the actual mass extinction events. We can go and look and see how much mercury those sediments have in them and because volcanoes are a major source of natural mercury so there's there are some other sources but they're one of the main ones and because it's it's a gas normally a gas and it gets a really long way from the volcano because of those things we can actually go and look at sediments from all over the world sedimentary columns and actually see if we can see the fingerprint of the volcano. So I'm just going to show you this one data here these are the carbon isotopes that give us the change in the carbon cycle that accompanies things like mass extinction events and this is from a core taken at this site B in Austria and what you can see is we get this this big spike in the mercury here so this is this red line around the entriassic extinction event here so we've got this this extinction here and the thing that was really exciting for me when I saw this is because with the central Atlantic magnetic province we actually have this interleaving of sediments with with some of the lava flows we could actually kind of almost tell which which lava flow of the central Atlantic magnetic province this came from and it was probably this this lower high atlas flow which basically just sits around this this this extinction event right here so what was quite amazing for me was to imagine the fact that this this flow here in Morocco that was was erupted about 200 million years ago pushed out to load of mercury that traveled a significant distance around the planet to this to be deposited in this sediment core here in Austria which was then sampled dug up by by humans and brought back to my lab in Oxford and that those those atoms of mercury were released as a little puff through my instrument that allows me to measure this and this gives this insight that this was actually a really big gas emission around the time of the entriassic extinction so this this is something that we're working on right now and we're hoping we'll we'll yield new insights into these associations between largely responses and mass extinction events and the other thing we're interested in as well is that you know I said earlier this we don't know that we've got an open question is this send or division extinction was it caused by something else or is it just that we've lost the volcano the evidence of the volcanism around this time because it's so far back in the geological record and there's lots that we need to understand before we can kind of really interrogate that but actually maybe we can use mercury in some of the sediments if we can understand the ocean the chemistry of the oceans going on around then if we can understand how the atmosphere was behaving and how mercury chemistry has happened perhaps we can understand if we can see a mercury signal here whether it tells us something about the cause of this this most enigmatic of mass extinction events so I'm going to end it there um what I really hope that I've convinced you is that there's many ways that volcanoes can affect our environment we can actually learn a lot about the impacts the environmental impacts of volcanism of the whole geological record as the whole of the history of our planet by looking at volcanic processes today and by sitting in in in volcanic plumes and making measurements and so I really hope I've shown a sort of link from volcanic vents to mass extinction events as my as the title of my talk suggested thank you very much we we've got a few questions starting to to build up for your time so I'll just try and get them into some some sort of order here but there's an interesting one from the early part of your talk Paul was asking is it possible that an asteroid impact could actually have set off the volcanic activity at the end of the cretaceous what are your thoughts on that one um yeah so so people have suggested this um I think the the problem with it is that the volcano the the the volcanism was going on before the asteroid hit so if we look at the iridium layer in the geological record and we look at the million years uh that the the decan was going on for actually the decan had been going on for a very significant period of time before the asteroid hit now of course when you get a big um when you get an impact of that scale um you know it would shake the planet up you get a lot of vibrations going on around the planet um and it is possible that that would have you accelerated the pace a little bit of the volcanism we might have had a slightly higher statistical number of other volcanoes going off around around the world uh but I I I don't think it's quite as simple as as pure cause and effect in the most in the most sort of black and white and straightforward way thanks Tamsen um now Tony Burton's asking a question here and it's it's to do with um with cooling rate really uh I think he's in I'm interpreting here I think he's interested in perhaps things like geothermal geothermal energy but he's asking about the the rate of cooling um does it cool as you know does it take as long as hundreds of millions of years to cool is it renewed um would you like to talk about the rate of cooling well um so so inside there's I guess there's maybe not immediately clear if you're talking about lava flows on the surface of the plant if you're talking about geothermal energy you're talking about kind of things going on inside the crust of course the the heat of the planet um is you know earth's earth's internal heat which is fundamentally what drives volcanism is is ongoing um some of it's leftover from primordial heat from from the heat that it had when it when the plant accreted but then we've also got a bunch of um different radioactive decay chains going on inside the rocks inside the earth uh which then release release energy and and maintain the the earth's inner heat so then when you get um magma's created by different processes so the you know there are there are a number of different processes there's the subduction processes where you have essentially uh water being released into the mantle and that changes the the chemistry of the mantle which then causes it to to melt changes the the melting point um and that can create magmas but then it's uh mid ocean ridges like Iceland and hot spots also like Iceland actually you've got lots going on there um it's because you've got a reduction in pressure on the on the on the rocks or a hot hot hot mantle rising up to a low pressure um and so it's that change in pressure a bit like you know trying to I don't know maybe no one if you ever try to cook uh cook rice or pasta at altitude you get a kind of horrible bloop uh because that that changes the boiling point of water so uh so that similar thing happens with changing pressure um on uh on the mantle there so once you've got magma's then those magmas are sort of fresh hot stuff at about a thousand degrees or more and and it's that that's that that that that that new heat energy if you like is then transported to the surface of the planet um and when you've got geothermal energy or you're tapping into that but that's that's sitting insulated inside the earth's cross so it'll it'll cool very slowly and and then potentially also be renewed by new pulses of magma coming up from deeper inside the planet. Thanks Tamsen there's another little questions come in um I guess relating to to to magma and the the internals of the the earth the question from Michael Bolton is to do with the renewal obviously the the um the gaseous coming off the emissions the particles um are coming out of the earth um is the is the pool that's left sufficient to keep sustaining that um how how is the scale of of eruption relative to the uh the remainder that's in the earth I think is the question. Yes I mean um the this is this I guess it's sort of related to the point about the fact that it's not like uh it's not a big pool of molten rock that we have inside the earth most of the earth is solid apart from the apart from the outer core so the magmas are being generated from the massive um reservoir that is the mantle and then finding their way up to the surface all stalling actually inside the earth's crust as well um and similar with the gases as well the gases are uh are coming from that massive reservoir in the mantle if you like or being cycled through so if you've got subduction zones where you have a plate going down um some of the water is is coming from being taken down uh in in the sediments in the hydrated oceanic crust that goes down into the mantle and then they find their way back up and similarly with with elements like chlorine. Thanks Amazon. A question here from from Neil Metcalfe um which is really I think relevant to your slides of the Pinutubo eruption and he's asking it's striking that the photo from the space station showed that the volcanic eruption created a very sharply defined band in the stratosphere and he's asking why the bands appeared to be so sharp yes that that would be the slide there yeah it's uh um I think it's largely a some optical effect so it's to do with the way that the light is behaving the uh I think I think uh from you know and also because you're seeing this in limb view which means sunrise or sunset to to uh in kind of normal language I guess um so so you know it's it's a it's a little bit similar to I suppose it's a it's a different sort of cloud and if you think about how sometimes clouds can kind of do this thing where they they kind of have the the darker edges or the lighter edges depending on what angle the the light is hitting it you can get these quite uh different effects and also what background um what the what's going on in the background atmosphere as well so you sort of got you have got this kind of um uh this this this sort of line sitting here which kind of maps onto this this line about here so we've got background optics going on as well as the uh the the fine mist of the aerosol haze optics as well but do take a you can find these photos these photos are on the NASA website and there's quite a long commentary about them so so I do urge you know it's a wonderful resource um so I do urge you to go and have a have a nosey you should be able to find them relatively easily I think it says NASA Earth Observatory website or something like that um but there's more photos similar to this um and uh it's a really interesting resource so do go and have a look at it if that's peach or interest. Right Samson I've got a nice sweeping question from Derma Kennedy here um and he's asking how important has volcanism been as an underlying force of history? Effects on famine plague migration war and how likely in the near future? Hmm goodness I was going to say I think we've got I think we've got some slightly different forces of history going on just now but the um yeah that's that's that's really it's a really really interesting one I mean sometimes it's hard enough in earth sciences to tease out cause and effect so then we when we start layering human history on top of that causing a teasing out cause and effect can be even more or even more tricky uh I mean um you can read all sorts of really fascinating things about this so there's sort of um I was reading the other day about a sort of theory about the link between the Mino interruption in Santorini um and the the you know the exodus the the uh the uh links with Egypt and the 10 play the plagues of the biblical times so so you know but it but it's very very difficult to actually kind of in that case draw the dates closely enough because we've got some patchy records on on both sides uh and more recent times there's some link stream things like the larky eruption in Iceland again and um impacts on on on harvests and um and food supplies and things like that and you know of course you know we know that we know that big political unrest can be triggered by an increase in the price of bread or something like this but it's often quite difficult to draw a really clear line of of cause and effect from the volcano going off to a particular event in human history unless the event of human history involves actually a direct interaction with the volcano um but yes I mean um teacher events I mean I don't really like to speculate we've got enough doomsday scenarios going on already uh right now I would say but but yeah certainly a very large scale eruption is always is always going to have um some some some sorts of geopolitical aspect to it as well could you I mean extend that question a little bit into work that's going on in predictability and perhaps unpredictability of of volcanism yes so I mean um I sometimes when I give talks of this I sort of get somebody who'll ask when's what's the next volcano that's going to go off um and I'll never be drawn on that because well first of all it'd be wrong to say it out loud even if you because you have to be very responsible about how you communicate uh those sorts of those sorts of predictions um you can say which volcanoes going off um which you don't need to be a volcanologist to look at the big volcanoes that are closest to massive centres of population and be able to say that if they went off very suddenly then that would have a big a big impact in terms of predictability we do have um there's a there's an always there's some interesting contrast with earthquakes and volcanoes um and with volcanoes we generally uh know where they are not always the occasionally occasionally a new one pops up but uh but we you're generally know where they are we we know where to we do have um the ability to monitor them and look for changes so I think there is a slightly different talk and I could probably talk for about 50 minutes on the subject as well um but there's lots of different techniques that we use um some of the challenges about it can be time scale so you know you can often look at a volcano and say yes that's going to erupt but you it's whether you can put uh it's going to erupt in the next two weeks or whether it's going to erupt in the next two or 20 years which is which is a problem so for the volcano think about how long their lifespan is two weeks two years 20 years that is kind of all in the it's kind of that's kind of a same chunk of time for for them but our lifespans are so very very much shorter but that's a really key difference for us so we're kind of interacting with an entity that exists on a really different time scale but one of the most exciting things I think for me at the moment is is the space-based measurements that we can make which uh which which again it's really a whole new tool but like for example we can now watch the the earth change in shape on the kind of centimeter scale um and we can do this with all the work we would not all but um a large number of the world's volcanoes and this is actually kind of allowing us to build up data sets and understandings understanding of kind of the um the whole the whole sort of population behavior of volcanoes rather than just having a few that we understand really well thanks very much damson so we're not going to get a we're not going to pin you down to three weeks on wednesday that way that's right a rainy tuesday in the now i've got a uh a more technical question here perhaps from from david webster and i think he's he's thinking about your uh slides showing the mass extensions and the questions are the unknowns about the or division period and he his question is there was a lot of mountain building and presumably volcanism during the or division in scotland are there any studies on links to extinctions then so so i mean the yes that there are there's volcanism going on throughout the geological period uh but it kind of needs to go a bit over and above to to to become one of these these these these nitrogenous provinces so yes there will be volcanism going on around the globe um at times absolutely in uh some of the beautiful volcanism that you have not too far from yourselves um but uh but but it's it's about whether you've got one of these one of these these massive prolonged province events going off which is which is which takes the whole kind of uh planetary average up for a million years if you like in terms of how much has been put out onto the surface of the planet okay a question here from john roland how well do we understand the extent to which sub-seval kinetic activity has and is currently impacting the temperature and chemical constituents of our ocean or another one i absolutely i um i've always wanted to go and study so i'm just trying to find i just wanted to get a map up i've always wanted to go and study submarine volcanoes but they're even more difficult to get to than uh the the sub the sub-area of volcanoes so i i think it's absolutely fascinating question um the thing we have been doing recently um with the uh so so we do have we do have understanding of some of the chemistry so for example for mercury uh we've got some uh cruise we've got cruises that go across the oceans so just for example there's cruises that go across the atlantic uh and take chemical data they they send they send instruments down to the bottom of the sea and come back again and they uh they collect the samples and they analyze them so you can then plot out what affects the the mid-atlantic ridge which is running uh running along like this um all the volcanism in the mid-atlantic ridge you can actually have a look at the sort of chemistry effect of the chemistry and the temperature and things like that but the mid-atlantic ridge is happening there's worth saying that you know most of the the world's volcanoes are under the sea so um it does really change i mean so the the ocean is an enormous kind of buffer if you like so it does sort of change in terms of and it circulates in a very different way to the atmosphere so it does it does sort of rather change um the the immediate impact that that these types of volcanism have on the planet but we have been looking as well at the impacts of these um submarine volcanics so the ontong java for example and the carabin so we've also been looking at the geological record some of the some of the ways that these have impacted the biology and ecosystems of the world so it's quite interesting because we can use different elements with different lifetimes in the atmosphere and the oceans to try and kind of tease out if you like um how far the sort of chemical horizons of the volcanism are getting in different cases the question goes on slightly just to you're touching on it but um john is asking can the effects of subseable kind of activity being be separated out from those of global warming um well the sub i mean the thing about the subsea volcanism i guess is that it goes on it's been going on over the geological timescale so what we're seeing in terms of global warming at the moment uh is is a perturbation it's not it's not part of the background so the the effects of submarine volcanism really are part of the background uh because there's no there's no evidence from any source that that that has changed in the last 200 years uh whereas there's plenty of evidence or several hundred years but there's plenty of evidence that our plans is changing in a bunch of other ways on that timescale um slipping a little practical question here from Pat Monaghan um i think she's been a bit concerned about you getting too close to the edge of some of these creators and asking can drones now be used to get samples of gases from volcanic creators yes yes they can so we do we do use drones um and uh um i was on a the last field trip i did was to Stromboli volcano in Italy uh and that was using drones to to sample the the plume there um i would sort of emphasize that uh that uh the the the volcanoes that i go to study are kind of by definition a particular type of volcano so right on the current web yeah right at this end of my my explosivity spectrum you know these are the most uh the the the safest approach that you can possibly make and even there i'm i'm sort of i would never i'm for example abseiled down into the crater of messiah although i know people who have um and uh and when you're up on the top of mount etna you're always there with the the local scientists and we're the most up-to-date information about the the activity state of the volcano thanks damson uh question here from john tweedy uh it's touching back on the the mercury question do you find that mercury emissions vary with different eruptions and do you find different proportions from as he puts it every day eruptions compared with those associated with mass extinctions well i suppose this the that's a really interesting question and the trick the the the the reason it's a really interesting question and i'm glad i've got this slide up is it sort of relates to the previous question actually is that we can safely make mercury measurements of this this bucket of messiah volcano this volcano here we can safely sit at the edge of the volcano there and make some mercury measurements but we can't sit in mount st helens plume um or we can't sit so we can't sit in these really ash rich explosive plumes and make and make measurements of the mercury coming out so we actually have less information about the mercury emissions in this type of eruption here um and whether they are less because uh because uh whether they're more because the gas is coming from deeper in the system whether there's any interaction with the ash there's there's lots of open questions which are kind of um we're limited in what measurements we can make but actually in terms of the large igneous provinces it is probably more like this hawaii type of activity and this uh messiah type of activity um that that they that characterize them actually rather than these these massive silica rich explosive eruptions so large igneous provinces tend to be basaltic which is the kind of less uh chemically changed end of of magma so they're the more runny magmas like on hawaii and messiah anetna for example um so actually we're sort of fortunate in that sense and I think our lack of ability to make significant measurements up at this end here of the explosivity um probably isn't the the uh as much of a problem as it would be perhaps for a super eruption for example in terms of mercury thanks Amazon I think we've got time for just another couple of quick questions here um another one from David Webster very specific question here was volcanic activity responsible for the palaeocene erocene thermal maximum um possibly yes so that was around the time that the north Atlantic igneous province was coming out so yeah this is one of the I can't remember if it's on um Vansol's um compilation here yeah so it's uh it's it's this this it's hidden unfortunately how I'll see if I can find it in the later one but yeah there is this association um with the the north Atlantic and a question again going back to the example of the pinot eruption and the question is what sort of effect on global warming is a one in one hundred year event likely to have yeah so it slowed down global warming so if you look at the if you look at the the average record you've got this kind of you've got this steady steady increase unfortunately the year around 1991-1993 is the flattening off um slight a slight increase I think in 92 I can't remember as well since I looked at it but yeah so I mean it's led some people to suggest that we should be putting aerosol up in our stratosphere in order to combat man man made global warming I think it's I think it's a bad idea myself I think that you could have a lot of unintended consequences so we did we saw things like changes in rainfall patterns after the pinot tuber eruption that were relatively subtle but if you got things wrong you know you you you could risk triggering inundations or droughts around the planet just to take one example of unintended consequences of course it might not be a direct trigger but it would be hard to prove cause of direct cause and effect with something as complicated as the the the annual the annual weather so so you might end up with a with international disputes arising from that thanks Tamsen I think that there's I'm being possibly corrected over an earlier question Tony Burton's question about cooling and um whether that's right or wrong you might like to could be asked you just to comment on the the renewal of heat um within the earth's core what is it explain for the audience what is it that keeps heat regenerating in the earth really so it's it's been it's been regenerate as I said so some of it is residual from accretion from when the planet was formed but but but then it's the it's the fact you've got things like uranium series uh um uh uranium you've got radioactive isotopes that decay um and when they decay they release energy and uh and that keeps the the earth warm so you know that um radioactivity can have a very long half-life and we've got a series of different decay chains that that keep the keep the inside of the earth hot it won't be hot forever um but but it's not probably our most immediate concern right now okay Tamsen thanks very much you refer to energy there well we we admire your energy getting through the last hour and a half thanks very much for a brilliant talk there's been a good number of comments about it superbly illustrated very relevant and um I I picked out your talk I just love some of your phrases which will um stay with me I love the the picture of volcanoes as you put it tracking out the periodic table I think that's a great one that's a new way of looking at volcanoes and um you're also very important in touching some of the last questions there how you illustrated the fact that a volcano which is in the news today tomorrow for a couple of weeks has such a lasting effect on on the earth and the earth's atmosphere and the temperatures of the earth um excellent demonstration of that and just to draw it to a conclusion I also loved your that put us in perspective didn't it your your example of humankind as the nail dust on the planet it's all put us all it put everything into perspective for us kind of thank you very much on behalf of the society for a brilliant talk this evening it's been more stimulating I'm sure there'll be lots of chat amongst people for uh days to come as a result of it thank you very much Tamsin that's okay thank you very much goodbye bye