N4 – Scale interactions in a warming Arctic

The Arctic is the fastest warming region of our planet, causing significant changes such as permafrost thaw and sea ice loss. In this project we work towards a better understanding of how small-scale surface inhomogeneities and extreme weather events influence large-scale Arctic climate dynamics and the global climate system as a whole. Combining climate modeling, fieldwork, lab experiments, and observational data, we investigate key interactions that could lead to non-linear dynamics in Arctic climate behavior.

Work packages:

WP1: Global effects of Arctic surface heterogeneity
Lead: Victor Brovkin

We will improve climate models to better simulate how small-scale variations in land and ice surfaces—like melt ponds and ice floes—affect regional and global climate processes. Using high-resolution remote sensing data, we will develop new parameterizations and run dedicated simulations to quantify how these surface features influence the Arctic's water cycle, greenhouse gas emissions, and sea-ice evolution.

WP2: Weather extremes and permafrost carbon
Lead: Lars Kutzbach

We will study how intense weather events, such as heatwaves and storms, impact the stability of permafrost and its stored carbon. Field research in Greenland’s tundra and laboratory experiments will help us understand how these extremes accelerate permafrost thaw and release greenhouse gases. This improved understanding will allow us to better estimate how such events influence long-term carbon feedbacks in the Arctic.

WP3: Instability and memory of Arctic climate elements
Lead: Dirk Notz

Building on insights from WP1 and WP2, we will use advanced climate models to assess how surface heterogeneity and weather extremes influence the large-scale, long-term evolution of the Arctic climate system. This WP focuses on understanding the long-term stability of critical Arctic components like permafrost and sea ice, and how their responses might lead to irreversible changes in the global climate system. The results will help us understand the resilience and vulnerabilities of the Arctic climate under continuing warming.