 Thank you very much and good afternoon So Does it work? Okay, so I thought a good starting point for this talk Is the last report by the IPCC where It is already mentioned that volcanic eruption may play a role for multi-decadal variability and actually if we look at the history of Volcanic radiative forcing basically this curve here, which is basically composed of intermittent and irregular spikes of Negative radiative forcing. I think it is clear that it is not straightforward to connect the forcing with the multi-decadal response and Actually if you want to understand the response we have first of all to understand Radiative forcing volcanic radiative forcing and I'm not going into any detail of this I want just to recall a few key points and I will use a Movie Yeah, okay, so the climatic impact or relevance of a volcanic eruptions stems mostly because they emit Sulphur containing gases and if the bloom of the eruption is strong enough to reach the stratosphere then it is quickly dispersed by the stratospheric circulation and the Sulphur species are oxidized into Sulphoric acid vapor which then condenses and leads to the formation of volcanic aerosols this in turn grow and eventually decay within a couple of years leading to Abundishment of the volcanic aerosol cloud and volcanic aerosols Have an interesting property so they can alter the relative balance of the atmosphere and they do so because they scatter shortwave radiation and They entrap a long way and near infrared radiation which means Of course that the tropical eruption of are of most are the most interesting In terms of climatic impacts because of course the albedo effect is Stronger, but also because the fact that the aerosol cloud is mostly confined to equatorial attitude. We have Warming of the equatorial lower stratosphere, which means that we have enhanced meridional Thermal gradient which in terms by thermal wind balance implies that we have strengthened at vortex Which in turn have a tropospheric signature which resembles positive phase of the NaO So just work. Okay, so of course a volcanic eruption that have money to large enough to affect the climate globally are rare events and During the observational period that there are just a handful of events and they were not really strong and I think it is difficult for anyone to spot the crack a tour or a chichon or a goon or pinatubo Just at first glance. So the point is that the much of what we know about the long-term response of volcanic eruption actually depends on information that we gain from Reconstructed events and the last millennium is already a good period to look at but this means that we have to deal with all the certainties that come with reconstruction and also that are inherent in the simulation of the response to these events and first of all, of course, we also need Reliable what kind of logical datasets and also Accurate Eruption chronologies as a starting point and this is the last attempt by Michael Siegel and co-authors So there are hints in climate reconstructions that volcanic eruptions are capable of inducing long-term Variability in the climate system and these concerns both high latitudes as shown here as Example but they work by give for Miller and co-authors in 2012 where they connected the onset of little ice age to volcanic activity during the 13th century and to the establishment of Long lasting Feedbacks between sea ice and the ocean circulation, but also there is recent work still based on reconstruction pointing to Prolonged response in the tropics, although the mechanism as I must admit it is not as clear as hoped in this case So I myself looked into some reconstructions and I specifically looked in some seasonal reconstruction for Europe and I found out that if we just look at about one decade after major volcanic eruption, there seems to be Extensive warming over Europe during winter Which is associated somehow over the North Atlantic to something that resembles a positive phase of the NAO and we tested that these Results accounting for a certainties in the number of eruptions that we looked into and Accounting for a certainty in the timing of the response and of the eruption itself and this seemed such a robust Result that we went as far as giving it a level and we named it delayed winter warming and the mechanism that we used to explain this feature actually share some similarities with the dynamical framework proposed by All algae author and co-authors in 2010. So basically the NAO plus anomaly that is established in the Winters immediately following the Derruption, which is kind of depicted here actually enhance turbulent heat fluxes Over the ocean convective regions, which then eventually leads to a strengthening of the Meridional over turning circulation in our case. We associated this feature also with the modification of the supolar gyre and to Enhanced heat transport into the Nordic sea which would eventually lead them to Anomalous heat fluxes in the bar and sea and enhances cyclos and as a cyclogenesis there so but this is one model and an average response if you want what happens if we look at one event and at the Different models. So this is what ding et al did in 2014 recently looking at the response to the cracker tower option In different models and what they found is that you can basically see That the models do not produce a robust results So the point is that is this just reflecting model uncertainty or there is something more and Some hints to an answer come from a study that we did before that so we actually looked at a large number of volcanic eruptions into a single model ensemble of the last millennium simulations and we found out that there is clearly some dependency in the Post-eruption anomaly of the MOC on their pre-ruption state So it seems somehow that the initial conditions matter in determining the response to volcanic eruptions And we decided to tackle that in a more systematic way and we decided to do that more in a more general framework accounting for all Uncertainty that could derive from background conditions. So we took the Tambora Eruption in the 1815 as a case study. So we created three ensembles one with all forcing one volcanic forcing only simulation and a volcanic forcing only simulation but excluding the effect of the 1809 eruption that preceded the Tambora and in the case of the old forcing simulation I just recall that The effect also of the Delta minimum of solar activity is included So as expected and on top here you see the global top of atmosphere Nitritative flux anomaly for the three ensembles and you see that For the Tambora eruption, there is no significant difference in the forcing and also if we look at the global surface Temperature response global average. So temperature response We see that there are differences, but overall the different trajectories kind of intersect each other So the differences are not really so relevant. This is not the case when we look at the oceanic response So if we look at the MOC strengthening, we see this is seems to be a robust feature In the tree and among the across the three ensembles. It doesn't really matter in this case whether The initial state is weaker or stronger, but if we look at Upper ocean potential temperature in the North Atlantic or even more in Arctic sea ice. We see that the Differences are kind of dramatic in the sense that if we have a Tambora forcing only simulation the blue curve here and here We see that the anomalies actually are kind of Small and also short leave not going beyond the range of internal variability here for a long time Whereas when we are in a full-forcing condition the black line We have that the system is pushed outside largely outside the natural the internal variability range For as long as the next big eruption occurs in the mid 30s So this is not just a matter of magnitude because the Dynamical part can also change and this may be relevant for For regional climate response for example if we look now at the ocean heat transport into the Nordic sea We see that only in the case of the full-forcing ensemble. We have a significant Reduction in the amount of heat transported in the Nordic seas and this has eventually Some effects in for dynamic response in such as the delayed winter warming that I introduced before So let's have a look at what happens inside the all-forcing simulation. So this is just These are just plots of northern hemisphere temperature Averaged to highlight the the evolution for the all-forcing Ensemble that I Presented before and these are compared with the reconstruction in black. So you can see that the different individual Realization can either trace the reconstructed evolution or largely overestimate the cooling but even more interesting is that if we just look at the Multimodal ensemble of Pima tree simulation of last millennium. We can see a similar behavior and also a similar range In the spread of the ensemble so we can just conclude that internal variability and the bulk of Uncertainties related to model characteristics for example How the different model generate the volcanic forcing starting from forcing input data Have comparable effects in the uncertainty and even more importantly this tells us that even in a with a perfect model uncertainty in the knowledge of Or related to the initial conditions is our limit into reproducibility of historical events. So let's have a look at Predictability there was a study out this year from the DS Wingadows and Swingado and co-authors and they on one hand looked at moderate events focusing on the Algunga response And they found that actually this strengthening of the MOC pops up robustly also For this kind of moderate events, but only in those models that spontaneously tend to generate Kind of be decadal variability in the MOC and not in the other models like the blue curve depicted here But I think most interesting Contribution from this paper is they actually they introduced This destructive interference by Volcanic clusters in the sense that it is really important The phasing of internal variability at the time Of an eruption in this case This work shows that the pinot tube eruption here actually occurred exactly In a way that it was counteracting the natural oscillatory behavior of The MOC after the Algunga eruption which becomes instead again visible despite a long-term Weakening trend if we remove the effect of the eruption Of course, this is just part of the story because the real climate is more complex and for instance This model is not able to reproduce this kind of a very sharp peak in the MOC around the 90s that is associated Possibly to the positive phase of the NAO that occurred during that time So How should we proceed based on this kind of multiple lines of evidence so On the modeling side, there is an ongoing activity which is called volmip. It stands for model intercom Paris on project on the response on the climate response to volcanic forcing and I am co-chairing this activity with Claudium team rec and Miriam Codrick Basically, it is a protocol driven activity. We want to Submit different models to Volcanic forcing that is as much constrained as possible And we want to focus on the response and understand how the different models produce different Responses based on initial conditions and very well constrained forcing as I said and we have a few Experiments that are focused on the Kedel climate response. One is a tempura simulation one is simulation for trying to reproduce The lucky eruption so a high latitude eruption and we have also a volcanic cluster experiment focused again on the 1809 Tambora option we have also Decadal climate predictability experiment which is a joint experiment with DCP P and the advantage is that Volmip is a simip endorse activity. So there are all the advantages of the Simip infrastructure and Also, we have already about 10 modeling groups that agreed to perform all of our mandatory experiments So concluding remarks actually, I don't have any strong point to make I would just like to highlight that There are still uncertainties and gap of knowledge that are still large And so I think we just started to slot in the many different pieces of the puzzle and actually did a quick search on Scopus with the keywords for abstract titles and Keywords something like that. So using volcanic the cattle climate and the volcanic climate only and you see there is There are a lot of publication about the volcanic and climate But if you just include the cattle and there are just a handful of papers published in the recent years, so If this is of interest, we should probably dig more into this. Thank you