 I'm Ben Marzion from the University of Innsbruck in Austria and I'm studying Glacier climate interactions. So what's causing glacial loss? I think everybody is taking for granted that it's actually humans that are causing glaciers to melt and it seems so obvious in a sense, right? Because we know it's getting warmer because of anthropogenic CO2 emissions and then we think okay if it's getting warmer then the ice is melting so obviously if the glaciers are retreating it has to be because of human actions. But in fact it's not quite as simple as that because if you imagine what a healthy glacier looks like, a healthy glacier is also melting all the time during summer so the lower end of the glacier actually has more ice melting each summer than snow is falling during winter but in a healthy glacier that ice is completely replaced by flow of ice from the upper parts of the glacier and where more snow is falling each winter then is melting during summer. And so now when you have the situation that the climate is changing you will start to lose more and more mass at the lower end of the glacier but that's still being replaced by the flow of ice from the upper portions of the glacier and that makes glaciers really slow to respond to climate change. If you just imagine you start melting the glacier from below and you need time to melt the ice and all the time more ice is sliding down the mountain from from the top that takes quite some time and for small glaciers that may be a few decades for bigger glaciers it may be a few centuries and if you go to the really big glaciers particularly in the Arctic it can actually be many centuries or even millennia. So the extreme example would actually be the Barnes ice cap on Befin Island in the Canadian Arctic which is still a remnant of the last glacial maximum so that's sort of still responding to climate change that happened 20,000 years ago. And so then when we see those glaciers melting now it means that yes probably they are responding to climate changes that are occurring now but probably they are also still responding to climate change that happened over the past couple of centuries and that's what makes it quite hard to distinguish between the two. So what we find is that essentially yes for the past few decades is mostly humans human actions that is actually responsible for melting of the glaciers but we can also see that there is quiet and evolution in that in the sense that glaciers melted at more or less the same rates as they are doing today around the turn of the 20th century so around well let's say starting from about 1850 and into the 1950s but the causes have changed for that. So in the let's say about 100 years ago what was really happening to the glaciers is that they were recovering from a phase that is called the little ice age. So a few centuries ago and up to about 1900 particularly the northern hemisphere was a bit colder than it is today and we are not entirely sure about the reasons probably it was both due to volcanic forcing but also solar forcing but the glaciers grew quite a bit during that time and then that phase was over around 1850 to 1900 depending on where you're looking at and so glaciers started to melt and so what we found is that even without any anthropogenic interaction glaciers still would be melting so they would not have adapted to the end of the little ice age yet but they would be melting at far slower rates than they are actually doing and so essentially what has been happening over the past 100 years is that anthropogenic actions have taken over from those natural causes and so in a sense the melt rate of the glaciers is more or less constant during the 20th century but now it's mostly humans that are responsible and 100 years ago it was mostly natural causes that were responsible. We're looking at a number of misconceptions one of them is citing a few examples of glaciers that are growing as a proof that global warming isn't happening. Yeah so you will always find glaciers that are actually growing in some places and there are many reasons for that. One thing is that even if the global mean temperature changes it doesn't mean that that mean change is happening on every place of the earth and compared to the entire earth surface glaciers are relatively small and so they are seeing quite a bit of those those spatial fluctuations of climate change and the other thing that is quite important for glaciers is that climate change is not consisting of temperature change only but we're also seeing precipitation changes and so what's really important for glaciers is the balance between precipitation so mostly winter precipitation how much snow do they actually get and the temperatures and there is mostly the summer temperatures and so it's relatively easy to imagine a situation where even because of climate change winter precipitation may be increasing and if that is balanced by increasing summer temperatures you would see no glacier change at all or if the temperatures are changing a little bit slower in a sense than the precipitation you could also get a glacier growing so it's really few places where that is actually happening but it's not surprising at all. How did you get into science and then into this area of research specifically? That's actually quite funny because it's really coincidental. I knew that I wanted to go in science in general quite early and essentially I wanted to do physics but I wanted to do physics where I could actually see and touch what I was working on so particle physics and also astrophysics and so on wouldn't have been the right thing for me and that's why essentially I actually went into oceanography so I studied oceanography so looking at how the ocean circulation is working and why it's working like that and from oceanography I got into climate modeling doing my PhD and then it was really more or less the well it was actually that my wife got a job in a particular place and so of course I also wanted to go there and then there was an opportunity where the people at Innsbruck University were looking for a climate modeler and in Innsbruck there's quite a tradition on glaciology so it was actually well it's the Institute for Meteorology and Geophysics but there's quite a big glaciology group and it was that group that was looking for a climate modeler and so now I'm sort of the link between the glaciologists there and the climate modeling so and I think it's actually quite an exciting field to work in at the moment. Do you do much science communication with the public or non-scientists? Yes in times where there is a publication and the press is interested right so it's it's not a very steady thing but sometimes I end up doing interviews on the phone or radio interviews or so for two or three straight days and then nothing comes up for a half year or a year so it's very on and off. So one lesson for me really is to think about what you're going to say before you're actually meeting the people who are going to ask you things because it's really easy to get caught up in ideas that you have while you're actually speaking and so if you have a point that you want to make it helps if you're actually clear about that point from the beginning and then one thing I think is to just try to be as simple as possible and don't be too disappointed if you know they're writing something that you actually weren't well that you didn't want to say in a sense or if they are misunderstanding you because most of the journalists at least the journals that I'm working with particularly in the newspapers in Austria and also Germany they don't necessarily have a science background and so it's relatively easy to create misunderstandings and I think you always have to give them some room as well and just keep doing it even though some stories may not come out the way you actually hope they would come out. Have you ever had much interaction with people who don't accept the science of climate change who reject it? No not really I mean sometimes it's that journalists sort of want to cover that site and so they ask me questions that I would expect from the so-called skeptics but well actually there was one case where sort of I took the initiative to talk to a climate skeptic because he was writing letters to the editor of one local newspaper all the time and they always kept getting published and so because the the points he had were not completely nonsense you know he understood part of the physics but he didn't get the whole picture I thought it might actually be worth to spend some time with him to try to explain how it's really how it's really going and so actually I invited him to come into one of my lectures for an entire semester and he was sitting there and he was behaving in a sense right so that that actually worked nicely and then afterwards we sat down for an hour or an hour and a half and talk those things through and then I actually at first had the impression that I really had sort of caused some thinking in him and then about a week later I received another email from him and it was as if nothing had happened right and that made me sort of disappointed but I guess there's also something I learned it's easy to spend too much time talking to single people let's say that right because there will always be people who actually don't want to learn and who don't want to understand and then I would say it's essentially a waste of time to try to convince these people to me it's really clear that most of what we are seeing changing in the climate at the moment is due to anthropogenic causes and there's really very little room for doubt about that