Andreas Schmittner Oral History Interview, December 21, 2017

ELIZABETH THORLEY: Today is December 21, 2017. I am here with Dr. Andreas Schmittner, a professor in the College of Earth, Ocean, and Atmospheric Sciences at OSU. We are in the Valley Library and we're going to be talking about his research, particularly as it pertains to climate change. But I like to start with your background-where were you born?

ANDREAS SCHMITTNER: I was born in Germany.

ET: That's where you grew up?

AS: Yes.

ET: What was it like growing up in Germany?

AS: Well, I was growing up in a small village of 1,000 people in the center of Germany and you know it was country life there.

ET: What did your parents do?

AS: My mom was at home and my dad was working for the German telecom, so in the 00:01:00phone company. It used to be a government, owned by the state, the company.

ET: Did you have an early interest in science as a child?

AS: No, I did not have an early interest. In fact, first I wanted to become a musician initially and only later changed my mind and studied physics.

ET: What was your academic experience like growing up as a child, in particular?

AS: As a child, well, I was in Germany at school and then my parents moved to Iran, to Tiran, for two years where we lived there. I went to German school there and then back again to Germany and then I went to high school.

ET: What was that experience like living in Iran?

AS: It Iran it was quite an experience. We lived in a part of Tiran the capital of Iran that no other foreigners were. We were amongst the Iranians there and I learned to speak Farsi, the Iranian language, and I played with the kids on the block, but now I have forgotten all of my Farsi.

ET: Did you have any mentors or was there an expectation within your family for you go to to university after school?

AS: No, in fact neither of my parents had gone to university, so I'm the first in the family, but there has not been an expectation of that. I think they were positively surprised.

ET: Did you go to university immediately or did you do other things before that?

AS: I did other things before that. I told you that I wanted to become a musician but I did not have any formal education or I hadn't practiced an instrument for a long time, like typically students of music do. I took a year out after high school for which I wanted to prepare for the music admissions program. You have to do a test to be admitted to the program. But already after a few months it became clear that I could never accomplish it, but I still had to take the year off. In Germany also at that time we had to do military or civil service, and I chose the civil service. I was doing that for two years after high school. After that this year off and after that I started physics in 00:04:00the physics program.

ET: What was it about physics that attracted you?

AS: I don't know. I guess my first thought was I wanted to do what I liked to do, which was music. Then my second thought was maybe I should do what I'm good and I was good at school and physics and math and I also thought maybe I can do something useful there.

ET: Did you have any experience with undergraduate research?

AS: With undergraduate research? No, I didn't.

ET: What influenced your decision to pursue further studies, or graduate studies?

AS: Well, maybe I should take that back because I remember I went as an undergraduate to the Alfred Wegener Institute.

At that time I started physics in Giessen near the town where I grew up near Frankfurt in the center part of Germany. Then I moved to northern Germany to Bremen. Then there was the opportunity to do an internship at the Alfred Wegener Institute which is in Bremerhaven at the North Sea, and there doing polar research and that's how I got into contact with earth sciences essentially. I did a little project there on sea ice modeling and that was my first contact with the field.

ET: You went to the University of Bern is that correct to study your Ph.D.?

AS: Yes, that's right. In Germany I first did a diploma thesis that involves already kind of a scientific research work for one year which was at the Alfred 00:06:00Wegener Institute in Bremerhaven on arctic atmospheric processes, in fact, I was working there and after that I moved to Bern in Switzerland where I did my Ph.D. That Ph.D. was then moving towards the ocean where I'm still working on right now.

ET: What was it like moving to Switzerland from Germany and what language did you take your courses in?

AS: The Ph.D. program does not have any courses, so essentially it's different from in America where you take classes, but in Switzerland and Germany essentially you're done with your classes and you only do research. You write a thesis. I didn't take any classes there but the language is German as well in that part of Switzerland where I was in Bern. The German that the regular people 00:07:00speak is quite different. It's Swiss German. It's quite different from the regular German. It took me about a few months to get used to it and to be able to understand everything that people are saying.

ET: Can you talk about what the physics perspective brings to your kind of research studying the ocean as opposed to say an oceanographer?

AS: The physics perspective I think is broader than oceanography in the sense that it includes atmospheric processes or ice processes as well.

ET: Your research was on the atmospheric hydrological cycle and influence on global ocean circulation?

AS: Right. The waterway transport in the atmosphere and how that affects the ocean circulation. At that time my Ph.D. thesis was already about the planetary scale, so the largest scale ocean circulation. That's sometimes called the great conveyer belt and that involves sinking of waters at high latitudes in only certain regions of the world's oceans where this sinking takes place, and then the waters move at depth to different places where they up well. That sets up this global overturning circulation and that has a specific pattern. For example, waters sink in the north Atlantic, but they do not sink in the north Pacific, even though it's also similarly cold there. The reason that the sinking 00:09:00takes place in the north Atlantic and not in the north Pacific is related to the salinity of the surface waters whereas north Atlantic waters are salty in the north Pacific. They're fresher and therefore they are less dense, because salinity also impacts the density of sea water. Sinking only happens in the north Atlantic because the Atlantic is salty and the atmospheric hydrological cycles, or the atmospheric water cycle, determines the salinity differences between the ocean basis. The atmosphere transports water vapors, so water evaporates in the Atlantic and then it is transported via the trade winds in the tropics to the Pacific where it precipitates and that is one process that makes the Pacific fresher. You would expect there's also water vapor transport at midlatitudes from the Pacific to the Atlantic because there we have westerly winds.

But the Rocky Mountains are in the way so the water rains out and doesn't reach the Atlantic and the combination of these processes, water vapor transporting the tropics from the Atlantic to the Pacific but this blocking of waterway vapor transport from the Pacific to the Atlantic at midlatitudes this makes the Atlantic saltier than the Pacific and then that creates, that sets up that pattern of deep ocean circulation that we currently have.

ET: Were you creating of computer simulations or models?

AS: Yes, that was my work at Bern. In my Ph.D. I was working with very simply zonally averaged ocean model that only has one good box across the whole basin from east to west and in the Atlantic but we had separate grid boxes in the 00:11:00Pacific so we could model the Atlantic and Pacific separately from each other. Those were very simple models at that time.

ET: Was anthropogenic climate change a part of your research at that time?

AS: It was, even though initially when I came into the Ph.D. thesis I had not even heard about anthropogenic climate change, so I was doing this out of curiosity to learn about the earth system. My supervisor there, Thomas Stokkar, he was already aware of climate change and that it may impact the ocean circulation and in fact that had been an influential paper published earlier by Manabe & Stouffer who said that global warming could lead to a slowdown of this overturning circulation and we followed up on that with a simple model, so we 00:12:00explored that.

ET: Did you teach at all as a Ph.D. student or is it just research-based only?

AS: It was mainly research, although I remember we did some lab supervising students that did physics labs. I assisted with that.

ET: After you were done with your degree you took a postdoc position at the University of Victoria in Canada, is that correct?

AS: That's right.

ET: How was that transition like moving halfway across the world?

AS: Well, it was exciting. It was great. I met my wife in Bern in Switzerland and she also came with me to Canada and we really enjoyed it. Victoria and British Columbia is a beautiful place. Also the research group there was very good and my supervisor he was super. He was very generous and also he gave me 00:13:00essentially complete freedom to do what I wanted to do, which you know, has happened for a researcher. I could explore my own ideas and I also worked with a somewhat more complex model, a three-dimensional ocean circulation model. In fact, the same model I'm working with today so that's kept some continuity from that point of my postdoc years is the same model we're still using. Although, we've much developed it and improved it from the time when I was doing my postdoc there.

ET: Why did you decide to return to Germany after that postdoc?

AS: Well, the postdoc ran out. A postdoc is temporary. At some point I had to 00:14:00look for other job opportunities. I applied for a few positions, faculty positions, which didn't work out and then I got the offer from Germany, so we went to the Max Planck Institute there.

ET: Did your research focus shift during your postdoc years? Did you take it into a different direction?

AS: Mm-hmm [yes]. When I was a postdoc in Victoria, I was still very much focused on the physics. But I became interested in paleoclimate and what happened in the past, and the issue became that when we tried to model the past ocean, if we have a physics only model that only has temperature, and salinity, and velocities in it, there's only very little data that we can use the compare 00:15:00the model to.

Most of the paleo oceanographic data that there is lots of data that exists, but most of it is based on biological proxies. For example, carbon isotopes measured on little tiny shells of vermin and frill that live on the sea floor. That gives us information about the carbon isotopic signature of the water but if you have only temperature, salinity, and velocity in your model which is the basic physics that is in there, you don't know how that would affect the carbon isotope of the water, so I noticed that it is very difficult to compare and validate the model results with real data from the sediment even though lots of lots of data exists, but just the incompatibility with the kind of data with 00:16:00what we had with the physical model was the issue that we had. When I came to Jena, I came into contact with people who had experience more with the biological side of things and this was at the Max Planck Institute for Biogeochemistry, I started collaborating with them and they gave me a code of a simple ecosystem model and I plugged it into the physics model of the UVic, the ocean circulation model, and I had very quick success after maybe a week or so after a few days it was running and I could produce plots and maps of productivity in phytoplankton, which is very exciting to me. So that got me fired up and enthusiastic and even though it took many more years to really 00:17:00calibrate the model correctly and make sure everything was working as good as possible. That was a start into the more biological and chemical components. Since then we've developed the model to include full ocean biogeochemistry carbon cycle, oxygen nutrient cycles. That was a major part and very important important part of my career to branch out into these biogeochemical processes.

ET: It sounds like you synthesized different models or code from different models. Do you write code as well?

AS: Yes. That was a very similar code that we received, just a four tracer: nutrient, phytoplankton, zooplankton, detritus, called NPDZ models. We've built 00:18:00upon them and expanded it. Now we have more phytoplankton groups. We also have not only one nutrient that we had at that time but we have phosphate and nitrate and also iron now included in the model. We've been developing it to make it more realistic, to include more processes that really happen in the real ocean.

ET: After your time with the Institute of Geosciences with the University of Kiel you came to OSU, Oregon State?

AS: Yes.

ET: How did you decide to come here? What was that decision and transition like?

AS: Again, my job at Kiel was temporary so I had to look for other opportunities 00:19:00and I knew that here at College of Ocean and Atmospheric Sciences was at that time they were looking for a climate modeler so I met Peter Clark at a meeting and asked him are you still looking for somebody. He said yes. So, I applied and it worked all out. I was very happy.

ET: What were your initial impressions of the university and Corvallis in general?

AS: Since we were in Victoria before we knew the west coast. So, we liked it there and we also like Corvallis for the same reasons. It's just the quality of life here, the nature is so close by, lots of hiking trails and you're close to the ocean.

You're close to the mountains. It's a wonderful place to live.

ET: How has your role as a teacher changed through your career?

AS: Well, I haven't been teaching very much but when I came here teaching is part of my job, even though it's a relatively small part. It's only about 1/3 of my time teaching, but I had to learn and I think I'm still learning. I'm still kind of improving my teaching.

ET: You teach a class on global warming?

AS: Yes, an undergraduate class.

ET: How has teaching that class changed from when you first started to now?

AS: It has changed quite a bit. I tried to make the class more interactive. 00:21:00Initially it was more of a lecture only class. Even though it's still based on lectures, I try to include more interactive components to it because I feel like I want to know what the students think so getting feedback from students helps me improve my teaching, otherwise I don't know what they learn or what they think. I introduced a few things that made the classes more interactive. For example, I introduced student summaries in which I asked a few students to recapture what we did in the last lecture and so at the beginning of each lecture the students recapture what we did last lecture. That way we come up to the state where we are, and we remind everybody where we are, but I also get the 00:22:00feedback from the students what they understood from last lecture and what was not so clear so we can go over things that remain unclear from the last lecture again.

ET: You recently published an open source textbook on climate science.

AS: Mm-hmm [yes].

ET: Why did you choose an open source format?

AS: Well, I feel textbooks are expensive and I just wanted to take that expense away from students that are already have high tuitions to pay. That was my motivation, and also to make it accessible to as many people as possible. Open textbook can be accessed by everybody, not only students.

ET: Now I'll move more to questions related to your research. Can you talk about how you used nutrients to model ocean cycles? You kind of touched on it earlier, but in bringing nutrients into your models-

AS: Nutrients in the ocean are required by phytoplankton to grow and so the ocean works a little bit different than land. Land plants also need nutrients, like you fertilize your plants at home to have them grow better. But in the ocean it is tricky because the phytoplankton have to live at the surface of the ocean because that's where light is. The absorption of light by water essentially makes the deep ocean dark. Photosynthesis can only happen at the surface at the top essentially 100 meters or so. That means in order to do photosynthesis phytoplankton have to be small, they have to be floating on top. 00:24:00If they were like trees they would sink to the bottom and if there was no light they couldn't do photosynthesis, so that's why they develop into small algae that float near the surface. But still there's a food web. The algae are eaten by zoo plankton. Zoo plankton get eaten by fish. Some of the detrital material, like fetal pellets for example they sink in the water column and that leads to removal of nutrients from the surface. Nutrients and carbon are removed from the surface and sequestered in the deep ocean. If there was no process that bring back those nutrients to the surface, the phytoplankton would just starve and they could not grow any more. But the circulation, the turbulence in the ocean, so the physics essentially, brings some of the nutrients in the subsurface back 00:25:00to the surface and allows phytoplankton to grow, productivity, and makes the whole food web possible.

ET: Why couple ocean and climate cycles together?

AS: Well, the ocean is an important part of the climate system. The large heat capacity of the ocean is very important for climate. The ocean also transports heat from one region to another region and this global overturning circulation that I mentioned at the beginning is part of that. It removes heat from the southern hemisphere, puts it into the northern hemisphere and it makes the north Atlantic, for example, relatively warm compared to the north Pacific. From a 00:26:00physical point of view, the ocean is very important for the climate system. But the ocean is also important from the biogeochemical point of view because of the process that I mentioned earlier, the sinking of organic matter to the deep ocean, that is called the biological pump, because it removes carbon from the surface and the atmosphere to the deep ocean. So it makes the atmosphere have less CO2 than it would have otherwise. Essentially it keeps CO2 levels relatively low in the atmosphere and because CO2 levels impact climate, through the greenhouse effect, that also then impacts climate so the ocean biology and biogeochemistry impacts climate through the carbon cycle.

ET: What are difficulties in coupling these cycles together with respect to 00:27:00making projections about future climate?

AS: Well, the interactions between the biology and the chemistry and the physics is one of the difficulties and the biology itself is so complex and diverse. There's so many different kinds of phytoplankton and zoo plankton that food webs are complicated, so it is not straightforward to model that and put that into a global model, but with all models we have to simplify and the way do it currently is just we have a few groups that we call phytoplankton functional groups, like for example diazotrophs that can fix nitrogen or diatoms that 00:28:00require silicone as a nutrient or other phytoplankton. We try to model these individual groups that are functionally different, but we cannot model each individual species of phytoplankton just because of computational limitations. Even with those plankton functional groups, the ecosystem models become quite complex. We started as I mentioned earlier in Jena I started with four tracers: the NPZD model. Those have four prognostic tracers. Prognostic is what we call those that we calculate explicitly at each time step and each grid point in the model. Now we have expanded the model to have 30 prognostic tracers because we 00:29:00not only include the biological tracers let's say in terms of carbon or nutrients, we also included isotopes, which adds to the total number of traces we keep track of in the model. You may imagine that if we have 30 prognostic tracers they are all interacting with each other or they're flux is from one to the other. It becomes quite complicated, so the code also becomes quite complicated.

ET: You mentioned the ocean, or deep ocean, as a carbon sink?

AS: Mm-hmm [yes].

ET: Does human caused increase in carbon or carbon dioxide in the atmosphere, does that change that carbon cycle between the atmosphere and ocean and does that change the deep ocean as an ocean sink?

AS: It does.

Since global warming changes the circulation of the ocean, it also changes the 00:30:00carbon cycle because the circulation is important for the carbon cycle. As I mentioned earlier, the circulation brings up nutrients for the phytoplankton, so if you stratify the ocean more, which is what global warming does. Global warming warms the surface first. That leads to more stable stratification. We use that word to indicate that it is more difficult to mix the surface with a subsurface, so there will be less mixing of the surface with the subsurface. It's like if you have a bathtub and you just put warm water at the surface, then that warm water, because it's more buoyant it would stay at the surface and would not mix with the underlying water unless you stir it up. That is the same 00:31:00thing as happening in the ocean. The surface warms also at high latitudes it becomes fresher because there is more precipitation. All of these processes lead to less mixing between the surface and the subsurface and that decreases phytoplankton productivity because there's less nutrient input into the photic zone, into the upper ocean, and it also changes how the circulation affects the carbon cycle, like this large-scale overturning circulation. We know that global warming will slow this circulation down. In fact, it is already measured to be slowing down right now. There are the first indications that we're seeing right now that early model projects during my Ph.D. for example, that Manabe and Stouffer were the first who projected that to happen. Now we see the first indication that it's in fact, indeed happening. It's slowing down and that slowdown will affect the carbon cycle. There's no doubt about it.

ET: How does that slowing down affect the climate, or, climate cycles, I guess? Does it have a dramatic impact on weather, for example?

AS: Well, it can. We know that the overturning circulation not only affects climate in the north Atlantic, so the movement of near the surface of waters from the tropics to the high latitudes in the Atlantic warms the north Atlantic relatively. That's why Europe is relatively warm. If you slow that heat transport reduces, so it will affect clearly climate near Europe. But the overturning also affects the tropics. We know that at least for large changes in 00:33:00the overturning that the intertropical convergence zone responds currently because of this circulation that makes the northern hemisphere a little bit warmer than the southern hemisphere. The intertropical convergence zone, which is the band of high precipitation near the equator is just north of the equator. It's just a few degrees north of the equator, but if that circulation was stopped or reduced dramatically, then that ban would shift to further south. Either at the equator or just south of the equator. The evidence for this is not only from models but also from paleo data that have shown that link between the ocean circulation and the intertropical convergence zone in the past. We're pretty sure that this is a robust process and if the ocean circulation was to 00:34:00dramatically reduce, we would expect the intertropical convergence to shift. That would mean large shift in rain bands in the tropics, which would affect many, many people and ecosystems in the tropics.

ET: As a scientist you have an active public voice on Twitter and the Climate Change National Forum. Why take on this active role?

AS: Well, I think the general public needs to be more informed. My feeling is that climate science needs to be better explained to the general public. There is what the public thinks about climate change and whether or not it is caused by humans, for example, is much different from what scientists think.

I go to conferences a lot and there is no question. It's a very rare to meet a climate scientist and there are only very few that doubt this or that kind of play this role down. Essentially almost all of climate scientists agree that climate change is caused by humans, the global warming we're seeing currently. Whereas in the popular, the general public only I think half of the general public or so or maybe a little more, but much less than the percentage of scientists believe that global warming is caused by humans. I think it's important to convey that message to the public because if we don't believe that climate change is caused by humans then we don't do anything about it. If it's not our fault, we don't need to do anything about it. But it is our fault. We 00:36:00are to blame for it and there are also important consequences if this goes on in the future. It will have dramatic impacts if it goes on unchecked. So, in order to avoid this we have to reduce greenhouse gas emissions. In order to come to that conclusion you first have to understand that it's caused by humans. I just want to contribute to reduce this discrepancy between what scientists think and what the public thinks. I think there's a lot of, I think, deliberate misinformation in the media about that topic and I just want to counter that and try to bring the science to the public.

ET: What has your experience been like communicating scientific information to non-scientists? Has it made you think about language differently, or-?

AS: Yes, and the undergraduate class that I'm teaching most of them are non-science majors, so that is helpful. In fact, the class is also helpful for my research. I think there is a nice kind of feedback. When you teach or try to explain the big picture you also get more aware of the big picture. Usually when you do your work you're focus on the little details. Of course the little details are important but the big picture's also important. Sometimes you can lose sight of the big picture when you work on the details. Communicating and teaching brings back that broader view, which I think is important for a 00:38:00scientist to have. I don't know if I was answering your question or not.

ET: Yeah, it does. I'm going to move to some broader questions on climate change. What were your earliest conversations on climate change like and how have they shifted over time?

AS: The earliest conversations-I guess that must have been during my Ph.D. time in Bern. I think at that time it became clear that climate change is happening and that it may have serious consequences. It was not so much in the public perception yet. That changed with for example Al Gore publishing his or making his movie An Inconvenient Truth, and other things that brought it more to the 00:39:00public. But I was mostly interested in the science so I was not really much interested in following the public debates about it, but I know that in Germany or in Switzerland at that time there was no doubt that the scientists were not doubted. There was not a pushback like in the U.S. When I came to the U.S. I noticed that there was so much pushback against science and scientists that I felt that was not happening in Europe. There may be a little bit of that but it's much, much worse here.

ET: Have you thought about why maybe what would influence that discrepancy or cultural difference?

AS: Well, that's hard to say.

I think there may have been this polarization happening here that is partly 00:40:00responsible for that. Kind of the group thinking and so that you know if you just only listen to a certain kind of news or media that perpetuates these lies, in my opinion, or these misinformations then you just believe that and that is much less happening in Europe. Then maybe in the U.S. there is a larger mistrust of authority in general, so that people are much more suspicious of government and authority than maybe in Germany or in Switzerland.

ET: Can you speak about the community of climate researchers here at OSU and how the institution facilitates collaborate environment?

AS: When I came here I was new to the U.S. system so I didn't know anything about how to write grant proposals and how the system works. I was really very fortunate to be welcomed into a group of paleoclimate scientists that were working together at that time in preparing a large proposal and they immediately trained me in the process and helped me with understanding how the system works and so I was very fortunate in that regard and that helped me a lot also to write my own proposals, to get started here in a new situation. CEOAS also in 00:42:00general is very collaborative. People work together rather than against each other and that is just a wonderful place to be because if you have a question about something you can just knock on people's doors and say hey, do you know about this? Usually as scientists they are happy to help and talk about what their interests are.

ET: How do you foresee, or do you perceive having to deal with or cope with funding cuts to climate change research in this particular political environment?

AS: I hope not, but I think one has to expect something like that may be 00:43:00possible. So, yeah. I mean in past republican administrations funding for climate science was not cut, but in the present administration we don't know. Everything seems possible. But I hope not. Now it is certainly there's lots of open questions and things we need to know about the climate system.

ET: What kind of policy changes would you like to see happen within the U.S. relating to climate change?

AS: Well, I hope that the U.S. gets back into the Paris Agreement. I think that was a positive step by the Obama administration. I was really hopeful at that 00:44:00time when that decision was announced. Withdrawing from it I think was a mistake. We clearly need to reduce carbon emissions. The whole earth does it. We're the only country that is not in the Paris Agreement at the moment. I hope that we get back to reason and back into that agreement and into collaboration with the whole world to try to address this problem.

ET: You've touched on communication earlier, scientific communication, do you have any other thoughts on changes to public education that could help Americans either better understand climate change or change their behavior?

AS: Yeah, I don't know. I guess it would be good if the topic was taught not only in the university but also already in school. I think it's happening. I'm 00:45:00not sure how broadly it is taught in school, but I think it would be important to teach about it at all levels.

ET: Are you hopeful about the future of the planet in the context of climate change?

AS: I am hopeful. My hope or despair changes. Sometimes I'm more optimistic. Other times I'm more depressed. It's an up and down depending on events.

ET: Well, that concludes our interview. Thank you for your time.

AS: Thank you.

ET: I appreciate your participation.