6 September 2023, by Niklas Keller
Where does carbon dioxide come from – and where does it go? At Universität Hamburg, Tatiana Ilyina is working to accurately represent these processes in Earth system models.
Welcome to Universität Hamburg! Since August, Tatiana Ilyina has been a Professor of Earth System Sciences, with a focus on modelling the carbon cycle in the Earth system. In addition to her research and teaching activities at Universität Hamburg, Ilyina will be working at the Helmholtz-Zentrum Hereon. In the following interview, she tells us why she’s fascinated by questions that hardly anyone has asked before, and which projects she’ll be tackling.
Prof. Ilyina, what are your plans as a new professor at Universität Hamburg?
What unites all my plans is modelling the carbon cycle in the Earth system. In terms of research, there’s plenty to do. After all, climate change is essentially a carbon dioxide problem. In order to solve it, we need rapid and strong decarbonization. This requires a predictive understanding of where does anthropogenic CO2 ultimately go. Accordingly, our goal is to more realistically represent the sinks and sources of CO2 and reduce the current uncertainties in our Earth system models. The focus is on the ocean, because it’s the largest carbon reservoir that exchanges CO2 with the atmosphere. Specifically, there are three areas that I’ll concentrate on.
And they are?
We want to predict how changes in fossil carbon emissions affect atmospheric CO2 variations and the climate. We need to know that in order to assess the effect of climate policy on the Earth system. Depending on natural climate variations like El Niño, the carbon sinks can be stronger or weaker from year to year. As a result, they can remove a larger or smaller percentage of human-made emissions from the atmosphere. That’s the first focus area. Plus, there’s another challenge. By now, we can fairly accurately simulate how the carbon sinks would respond to rising CO2 emissions. But we know very little about what would happen if successful climate mitigation rapidly and substantially reduced those emissions. In a project at CLICCS, I want to shed light on this second focus area.
And the third?
It has to do with high-resolution Earth system modelling: Even if our models of the oceanic carbon cycle were perfect, they would still need to realistically represent the ocean’s circulation. The models need to include small-scale ocean processes like eddies. Our configuration of the ICON model can already produce simulations of the oceanic carbon cycle at a resolution of roughly 5 kilometers. As such, it can represent small-scale features of the ocean’s circulation and biogeochemistry that couldn’t be simulated before. In addition, with a focus on coastal ocean, higher resolution, and a more detailed representation of biogeochemical processes, the model offers new opportunities for investigating the land-ocean transition zone – that is, where humans interfere with the environment the most.
What role does the Cluster of Excellence for climate research CLICCS play in your work?
I’ve been part of CLICCS from the beginning – in the projects “Earth System Variability and Predictability in a Changing Climate” and “The Land-Ocean Transition Zone”. In these projects, we concentrated on the ocean as a carbon sink and asked ourselves: Where are the biggest knowledge gaps? What processes is it essential to include in the model? The new focus areas for my professorship are based on these insights. That’s why CLICCS is very important for my research.
How is your research divided among the different institutes?
My position is a joint appointment by Universität Hamburg and the Helmholtz-Zentrum Hereon. There will be a lot of collaboration between the two institutions, so that everyone can benefit from the research. At the Max Planck Institute for Meteorology I continue to lead the group Ocean Biogeochemistry. When it comes to setting up my new cross-institutional working group, I will combine the traditional research strengths of these institutions. My goal is to address new frontiers in modelling the carbon cycle in the Earth system.
Does Universität Hamburg feel like home? After all, you finished your doctoral studies here in 2006 and habilitated in 2022.
Yes, it does. I first came to Hamburg in 2002 and felt at home right away. After finishing my Ph.D., I was a postdoc at the University of Hawaii, followed by a short research stay at the Danish Meteorological Institute. Already back then, I had plenty of contact with scientists based in Hamburg.
I’ve been working at the Max Planck Institute for Meteorology for nearly 13 years now. Hamburg is the heart of climate modelling in Germany. It’s home to the German Climate Computing Center (DKRZ), the Helmholtz-Zentrum Hereon, the Max Planck Institute for Meteorology, and of course Universität Hamburg. As a result, it brings together experts from a wide range of fields. I’m very happy that I’ll be staying in the Hanseatic city.
Until now, you haven’t done a lot of teaching – but that will change now that you’re a professor. Are you looking forward to it?
I’ve always wanted to share the findings that fascinate me with students. I’m particularly interested in the carbon cycle in the ocean and its essential role in ecosystems and the climate system. In my lectures and seminars, students will feel my passion for those topics. I want to clearly put the carbon cycle in the spotlight – in the context of the Earth system and how we can model it. My goal is to show what exactly we need to know in order to comprehensively grasp past and future climate change.
Where does that passion come from?
After my habilitation colloquium, my Ph.D. advisor told me: You’ve accomplished something that would have been impossible just twenty years ago. It excites me to gain new insights and find the answers to questions that, until now, virtually no-one has thought to ask.
In addition, this allows us to provide policy-makers with more detailed recommendations. For instance, my working group showed for the first time that changes in CO2 fluxes between the ocean and atmosphere can be predicted up to six years in advance, and changes in the atmospheric CO2 concentration can be predicted up to two years in advance. Now these predictions are being included in the annually released “Global Carbon Budget.” Receiving that kind of recognition for my own research is something that makes me especially proud.