 Okay, hello everyone. I apologize for not being able to attend, but thanks for giving me the opportunity to talk anyways and so I'm going to move away from the sea ice and actually look a bit more at the land ice, the two polar ice sheets and the context here, of course, is the interest in the global, the contribution to global sea level rise. I'll be focusing mainly on what the observational records show us of the recent past and what's shown here is a table from the IMBI group to that have attempted to reconcile an estimate of different contributions to sea level rise and Greenland and at ACPICA shown here the encircled portion the equivalent sea level rise contribution from 92 to 2008 here on the left side, but then you can see an increase on the thousands onward from 0.6 millimeter per year to 0.8 millimeter per year. Clearly those numbers are still fragile, but there is certainly is a context of what is happening and I'm going to show a little bit of both ice sheets So this panel, the left panel here shows flow velocities in and ACPICA these have been obtained from interferometric synthetic aperture radar and see these very large two ice shelves here, the runner ice shelf and the rust ice shelf and you have very large flow speeds exceeding three kilometers per year here in the western Arctic sector, the Amlundson sea embayment also shown in this panel are mass loss, which is still estimated from flux gate methods. You see these very large mass loss in bigotons per year again in the western Arctic sector, but you see muted mass loss here over the east and ACPICA The right panel shows ice shelf or thickening, ice shelf is the portion of the Arctic ice sheet that is already floating on water and you see again very large thinning rates here in eastern ACPICA and either no thinning or slightly thickening rates here in some parts of the eastern Arctic sector Similar story told for Greenland The top right panel shows you mass loss as import from satellite grab-teak base mission. This is mass loss between 2003 and 2011 You see these very large mass loss rates near the marine margins here from the southeast Greenland In fact, the signal that the time is propagated from the southeast into the west and the northeast Greenland Slight mass gains are seen in the, sorry, in the Greenland interior In the bottom left panel here shows the cumulative mass normality in Greenland from 2002 to 2014 and you see clearly this downward trend and potentially even an acceleration The acceleration, true, I've confirmed, would mean that Greenland is now contributing to more than a quarter of sea level rise and the cumulative freshwater anomaly, although overall the fresh water fluxes from Green are still comparatively small compared to Arctic interior variability. You start over the period to accumulate a significant amount of freshwater from Greenland The bottom right panel again shows surface height changes So very different measure, but again see these very large thickened rates in the southeast and again west and northwest Greenland So both ice sheets they have in common is that you see these large change rates Especially ice sheet and shelf thinning, increased mass loss, increased flow speeds You see these at the at their marine margins and The observed changes, the time scales of the changes are From these observations are seasonal to decadal And so the question is why bother in the context of decadal climate variability? We always had this notion that ice sheets are sort of these small slowly moving elephants that Don't do much decadal time scales. We took it forward for longer periods But in fact these satellite observations and other observations indicate that There's very large changes that are happening and for which decadal climate variability may actually be an important contributor and These large-scale climate coarsings may trigger small-scale processes that Might amplify these observed ice sheet changes These are surface melting, submarine melting, carving or weakening of the shear margins and the questions are What are the major goals of these changes? These are the dynamical Responses, experiments of the ice sheets. This has been one of the major unknowns in IPCC AR4 and I would say still for AR5 Atmospheric ocean circulation changes or top graphic controls So I'm going to focus really here on climate variability because that's the context for this workshop and We'll look look at Antarctica to get certain Celsius here So Antarctica large parts of significant parts are green-based You see the top right panel as a cross-section through parts of the Western Arctic ice sheets here And it would be a modern day and you see that the Western Arctic ice sheet is grounded Well below sea level up sometimes exceeding 1,000 meter below sea level What's also the case is see this bottom left here from Pritchard et al plotted the bottom temperature of the ocean adjacent to the ice sheet where you see insert parts with large continental shelves See here the Waddell Sea, the Ross Where the ocean interior is far removed from these large ice shelves in contrast that This is here like the almonds and sea and vehement where these warmer waters and in some sense the parts of the ACC the southern branch of the ACC Can get very very close to continental shelf Here in this area in other areas for example the the peninsula So this is an interesting interesting barrier to the potential mechanism that brings warm water up on the continental shelf and Into these ice shelf cavity and the vicinity of grounding ice and under the ice shelf So it's the right panel here shows us such a schematic for a bio from my Christian truth 2010 Zooming in to Amps and sea and vehement and Pine Island Glacier, which is Exhibited some of the largest change We've observed in Antarctica You see the top right panel shows the temperature Sort of off an offshore of the of the continental shelf very warm So computer deep waters that are Trying to get onto the shelf into this cavity and Pine Island is on the on the right Bottom corner here and the bathymetry is shown also in the bottom panel here shows you that There is The warm waters may be able to reach the tablet through two distinct tracks in the system So observations hydrographic observations have been taken in the almonds and sea and vehement for example 2009 and 2012 and From the paper deteriorate how they show the the potential temperature profile along the sections here the top 2009 the bottom panel for 2012 and what is noticeable is that in There's a very important change in thermocline depth between 2009 and 2012 period Which means that in 2009 and shallow thermocline There was a potential watch of the circle for the deep water to enter the cavity compared to the situation in 2012 and It turns out now that this thermocline depth variability Is determined by arms and sea and vehement wind anomalies, which in turn it seems are modulated by linear 3.4 teleconnections and To show this in one tail You see here on the on the right New panel type series of surface wind anomalies the unfiltered anomalies are Black curve you see here and little filters overlaying here is the is the red curve and also show Surface temperature anomalies in the new 3.4 box green and the middle panel shows the results when the knock is for in the region of interest here in the almonds and sea and vehement again and the bottom panel What appears to be the Teleconnections that click Surface temperature novelties to what's happening in the almonds and sea vehement similar stuff patients has been made by Show these very important potential influence between as the anomalies here in the tropics and in the high latitudes See bottom panel correlation in the new Foreindex wind anomaly that exceed 0.5 in again the region that is To be the almonds the in bed So an interesting sort of biometric focusing of what's happening in the almonds and sea vehement This was other business as well Spends at our explorers model base studies the impact of shifting southerly Southern hemisphere west elites and specifically they consider the shift by order of four degrees southward and also increasing in the amplitude of these wind strengths notes sort of an important impact on the eggman pumping The content in fact what they see is weakening of the near shore at eggman pumping So weakened postal cards, which in their models that the the kids a near shore pumping Will basically bring warmer water that is otherwise sort of Subdued to the continental that to the Antarctic slope front Broad streets now you're too higher to the surface and in the context of what we're looking at This is that more of that water might be able to enter those those ice shelf cavity a bit more explorative helmet our Investing it the potential for potentially large changes the wed-alcy and filter the runner ice shelf conducting So a couple of climate model simulations of the 20th century they They do notice a bit of similar mechanisms, but Additionally, another mechanism is to reduce the ice cover which changes more the near the near first-order Windfield and that changes wide ranges in the coastal current and brings much more water In and under the filthy the runner ice shelf then then we can see today So there's three mechanisms all sort of really climate forcing related that that we would sort of discuss in the context of climate variability that But might play a very important role in getting an understanding of what the polar ice sheets are doing now moving on to agreement again to some Processes that we see here This is a schematic here shown is the sort of the inflow of warm sail and Atlantic water of sub-tropical origins to the Nordic seats and into me and to the sub-polar gyre What we have been observing is that there's since the midnight 90s More warm and salty waters of sub-tropical origins have reached margins of green Ice sheets the agreement map was actually superimposed are and thinning rates derived from Laser altimetry from the ice set mission. This is from Pritchard at all And so just to your subject of very familiar with changes in the sub-polar gyre It'll be a big tea for example this study by academic and Ryan's 2004 2009 Updates and there's a more recent updates as well. Look at this in the cut of altimetric changes so More weakest the surface height in the sub-polar gyre, which is Related to weakening of the sub-polar gyre the slowdown and warming again is So far there's a mechanism to bring warm more warm water in in the vicinity of the Greenland ice sheet, but we also should not forget in the surface changes in top of meaning I should have also been important the right panel here is from box at our 2013 that shows changes in surface at a genomic is all the greenland These are nominees related to 1951 to 1980 So these anomalies show very large changes again since the since the 1990s and they would do is to bring Unprecedented surface melting in Greenland and so we have two two drivers of We have two drivers Can then prove they can precipitate these changes the one are sub surface water forms of water that reach the the Greenland ice sheets who these now fjords get in contact with the terminus positions But also surface milk water that That's basically our drains to the base of ice sheet and then provide a large runoff and the importance of these Mechanisms is shown in trend in translating them into melt rates and melting Provide of course by by warmer subsurface waters, but they could so be Idiated by these fresh water it would has runoff that provide a strong freshwater source and through some dynamics can find Melt at the at the base of the ice sheet by So so in that sense these two related but different processes Can enhance melting terminus positions enhance calving and through this to be thermodynamic effect can have a dynamic Impact on on ice sheet. We should we should not forget that oh that surface as well as women is important contributor to to the overall mass change and the surface ice sheets here the top right panel is and reassessment of the balance between contribution of what's called the Discharge, this is the the ice discharge of carbon and the surface mass volume secret just runoff changes and You see that what the earlier parts of these this philandium we have a slight domination of the of the of the discharge since recent years a surface balance seems to be a dominant driver and Fike it out have pointed out that with increased thinning of the green and ice sheets We will have larger variability in the surface mass balance just because of the more more parts of the Area of green will be the ablation zone of the ice sheet We are going now also to work Centennial reconstruction of what has happened in the ice sheet to try to Again make a connection between some of the chains that we see the in margins at this Margins and those two such fine indices as the North Atlantic oscillations and with this I Loot so I would argue again and others in our community that decadal variability is relevant for the problem of ice sheet changes in the context of understanding recent changes and also predicting potential future contribution to global sea level rise Also mechanisms despite of what showed you will remain rather uncertain and so this so a lot of this is sort of evidential But one of the major problems that we have the observations are very sparse They're challenging to obtain especially into context of process studies at these very difficult to access interfaces And obviously the types there is a way to short in duration to say anything about really variability in the true sense of what is being discussed The detail process understand is required to unravel the link between climatic forcings and the major response And what we actually do need is both small-scale difficulties to unravel some of these processes But then also long to monitor at the marine margins to actually get a very good record that is relevant for climate studies and so I See that this is a fundamentally multi-disciplinary and international challenge and challenge for which Climate Dynamics and Clive are have a role to play Thank you for your attention Thank you Patrick and thank you for waking up so very early to give that presentation in Texas sure Okay, are there any questions for for Patrick? Okay, hold we're waiting for some questions from the audience here. Okay, so in the previous talk This is Paul here. There was a discussion of impact of Cloud processes on on Greenland and I guess that plays into the role of the surface mass balance that you raised right at the end and so What do you see any sort of? Could you synthesize any challenges for us to discuss in the afternoon about how we could better coordinate those studies of Say cloud processes and focus on I guess you need to say focus on Greenland itself as a starting point. Yeah, I Think so Yeah, I think so because the so of course a lot of attention is paid to ice sheet ocean interactions but I hope to convince you that actually what's happening on the surface of Greenland is a very important contributor in terms of a buoyancy source that might amplify the melting at these terminated positions and So there are some attempts now to develop some process studies process understanding through a detailed observations and you know try to you know cause and effects and in that sense I think clouds as far as I can see it's it's not perhaps being discussed in the context of such a modern monitoring system and So I think that basically exchange that extends this chain of Mechanisms that we perhaps need to understand to order, you know to translate what's happening at the surface of the ice sheet or the atmosphere It's a bit of a not quite an answer But I think it would be important for process understanding to link this to the climate variability over Greenland to runoff which is very very difficult to measure at the terminus position and subsequent melting at the terminus Okay, thanks. Are there any other comments or questions? All right, thanks very much Patrick. Well, thank you Yeah