I am Professor at Universität Hamburg - being part of an exceptional setting of climate research and teaching at the Faculty of Mathematics, Informatics and Natural Sciences. Since August 2023, I founded a new Research Area Modeling the Carbon Cycle in the Earth System in the Department of Earth System Sciences, as well as a new Department Earth system modeling at Helmholtz-Zentrum Hereon. My working group is transitioning from the Max Planck Institute for Meteorology, where I still continue as Lead of the Ocean Biogeochemistry Group. Learn more about my research plans here.

Ongoing climate change is essentially a CO2 problem. It can only be solved by strong decarbonization measures drastically cutting CO2 emissions. Thereby there are fundamental uncertainties in our understanding of how the carbon cycle and feedbacks change. I directly address this one of the most pressing problems of our time through my research. My research interests lie primarily in the area of the ocean carbon cycle, its variability and predictability on decadal time-scales, as well as its impacts on Earth’s climate via the climate-carbon-cycle feedbacks on centennial to millennial time-scales.

My research philosophy has been to address these topics with Earth system models (ESMs). Together with my group, we develop the model HAMOCC (HAMburg Ocean Carbon Cycle model) as an interactive ESM component and the main tool to test our ideas.  We focus on ESM simulations enabled by interactive carbon cycle. In this way, variations in atmospheric CO2 concentration are computed prognostically and are directly modulated by the ocean and land carbon sinks. By resolving carbon-climate feedbacks, such approach enhances the realism of ESM simulations and better informs on their uncertainties. It furthermore allows computing how climate and carbon sinks respond to changing emissions during decarbonization and provides a direct link between policy changes and the Earth system.

Together with research students and post-docs in my group, as well as with external collaborators, I address knowledge gaps in our understanding of the following research questions:

• How does the ocean carbon sink respond to rapid climate change events?

• What are predictability horisons for the natural carbon sinks and atmospheric CO2 growth?

• What is the role of internal climate variability on the ocean carbon sink?

• How meso- and submeso-scale processes in the ocean impact the ocean biogeochemical cycles?

• How did changes in ocean circulation shape the biogeochemical cycles during ancient warmings and the last glacial cycle?

• What are the impacts of artificial ocean alkalinity enhancement in the Earth system?

I contribute to advancing the international climate science as co-Chair of the Working Group on Coupled Modeling of the World Climate Research Programme.

I am actively recruiting PhD and MSc students, as well as postdoctoral researchers under the broad themes listed above. Specific projects are usually advertised separately. Do not hesitate to get in touch to discuss potential projects! 

Recruitment opportunities in my group

Postdoctoral | Research Associate within the project funded by the European Union’s Horizon Europe "Artificial Intelligence for enhanced representation of processes and extremes in Earth System Models" (AI4PEX) studying biogeochemical impact of the individual and compound ocean extreme events based on high-resolution ESM simulations and observations by leveraging ML methods. Position description and application instructions

We are at the EGU 2025 General Assembly - visit our presentations:

Predictability and feedbacks of the changing ocean carbon sink – insights from Earth system models |Fridtjof Nansen Medal Lecture by Tatiana Ilyina

CL4.9: Advancing Ocean Biogeochemistry in the ICON-XPP Earth System Model for CMIP7 Contribution | Fatemeh Chegini

OS1.6: Impact of Mesoscale Eddies on CO₂ Fluxes in the Southern Ocean | Mariana Salinas Matus|ECS

BG1.2: Hurricanes trigger ocean CO2 uptake and phytoplankton bloom in a high-resolution Earth system model simulation|David Nielsen|ECS

OS1.13: Impact of submesoscale flows on primary production and export fluxesof carbon in the South Atlantic Ocean | Nuno Serra 

BG1.2: Contribution of storm-induced outgassing to the CO2 air-sea flux in the Southern Ocean in a high-resolution ICON | Arjun Kumar | ECS

OS4.3: Ocean compound extreme events under emission reduction and negative CO2 pathways | Danai Filippou |ECS

CL4.13: Understanding the mechanisms driving the ocean’s anthropogenic carbon reservoir under changing emissions | Hwa-Jin Choi | ECS

CL4.13: Asymmetric carbon-climate responses to cumulative emissions under different CO2 pathways | Hongmei Li

CL4.11: Different time scales in the transient response of the ocean carbon and oxygen cycles to deglacial climate change | Bo Liu

CL4.11: Impact of past AMOC disruptions on ocean oxygenation | Eva Rückert | ECS

BG1.2: Improved air-sea CO2 flux estimates by adding sailboat measurements | Jacqueline Behncke | ECS

CL4.11: Advancing Climate System Understanding: Insights from the PalMod Project | Kerstin Fieg

Research Highlights