Interview: "Implementing ice sheets in Earth System Models is crucial to understand their interactions with past, present and future climates"

In this interview, iC3 researcher Petra Langebroek explains her work on integrating the Antarctic ice sheet into Earth system models, what it means to be a modeler, and the importance of understanding ice-ocean interactions.

Could you describe yourself, your research focus, and how it relates to iC3?

Hei! My name is Petra Langebroek. I am a research director and senior scientist based in Bergen, Norway. My expertise lies in ice sheet and climate modeling, focusing on both the Greenland and Antarctic ice sheets. My work spans various timescales, from deep in the past to present-day and future projections.

At iC3, my role is to integrate the Antarctic ice sheet into Earth system models, which combine climate, ice sheets, and the carbon cycle. Historically, these models did not capture ice sheets, but we are now working to include them to better understand their interactions with the climate system.

Credit: Andreas Graven & Petra Langebroek

Why is it important to include ice sheets in Earth system models?

When I completed my PhD in 2008, it was believed that the Antarctic ice sheet would remain relatively stable. However, we now know that Antarctica is changing much faster than anticipated.

The Southern Ocean is warming, causing ice shelves to melt and the inland ice - the ice sheets - to retreat. Ice sheet melt directly contributes to sea level rise. This is particularly concerning for me as a Dutch scientist, given the implications for coastal regions.

Beyond sea level, changes in Antarctica affect ocean circulation, nutrient distribution, and carbon uptake, making it essential to couple ice sheets with climate models to understand these feedbacks.

What does it mean to be a modeler?

As a modeler, I use physical equations and mathematics to simulate and explore processes that are difficult to observe directly. Models allow us to test "what if" scenarios, such as the impact of increased carbon dioxide or ice loss on the climate system.

While observations are crucial for validating models, they cannot predict future changes or fully reconstruct the past. Modeling bridges this gap, enabling us to understand complex interactions and make informed projections.

How far back in time does your research go?

It depends on the project. For iC3, my work focuses on implementing ice sheets into Earth system models, which requires a lot of technical work, and is more present-day and future oriented. However, in other projects, I collaborate on studies examining past climates, such as interglacials in the Quaternary or periods like the Miocene and Pliocene, going back millions of years.

How do modelers ensure their results fit observations, especially for the past?

We validate models by comparing them to present-day observations, such as precipitation and temperature. We adapt the model parameterisations until the model simulates a present-day state that aligns with current data.

To simulate the past, we change the forcing, for example of carbon dioxide, and run the model again. This process involves uncertainties, as past data is often indirect, such as data retrieved from ice cores or sedimentary records. By testing different scenarios, we can better understand past climates.

Can you give an example of a concrete application of your current research?

One focus is on understanding how warm ocean water interacts with Antarctic ice shelves, melting them from below. Collaborating with colleagues, we develop algorithms to model these interactions, which are crucial for coupling ice sheets to the oceans around them.

This work helps us predict how ice loss might impact sea levels and the global climate.

Credit: Kristin Richer & Petra Langebroek

What technologies or methodologies excite you most in your field?

I am both excited and cautious about AI and machine learning. These tools promise faster and more detailed modeling but risk losing the physical understanding that underpins traditional numerical models. 

Can you share a memorable moment in your research?

One special experience was participating in a deep ice core drilling campaign in Greenland. As a modeler, I usually work behind a computer, so this hands-on fieldwork was a unique and rewarding opportunity to contribute directly to data collection and experience how it is to be on the ice.

How would you allocate an unlimited research budget?

I would invest in developing advanced models that combine physics and AI, enabling faster and more detailed climate information, preferably resolving processes and interactions that we cannot simulate in our traditional models.  

What big question would you like to answer in the future?

I want to understand how much, how fast, and where ice sheets are changing, particularly in relation to tipping points in Antarctica. These changes could have profound implications for sea level rise and global climate systems.

If you could change one thing in science, what would it be?

I would foster a more collaborative and supportive environment. While competition drives progress, it can sometimes lead to unnecessary conflict. A kinder, more cooperative scientific community would benefit everyone.

What does an ideal day off look like for you?

I enjoy spending time in warm, sunny places, preferably dry and not slippery. Whether it's relaxing on a beach or hiking in the mountains, I value outdoor time with my family.

Could you share a book or movie that has influenced or touched you?

I enjoy disaster movies, and recently rewatched The Day After Tomorrow with my kids. While dramatized, these type of movies highlight how Hollywood portrays realistic topics in exaggerated ways, which I find both entertaining and thought-provoking.

Do you have a personal motto or final thoughts to share?

My advice is to do what you enjoy and trust that things will work out. Life is full of challenges, but with time everything eventually falls into place.

Petra Langebroek is a research director and senior scientist at the NORCE Norwegian Research Center and associate professor at the Department of Geosciences at UiT The Arctic University of Norway. Her research  focuses on how ice sheets interact with climate. She is particularly interested in where and how fast ice sheets are changing, particularly in relation to tipping points in Antarctica.