Further Research into Arctic Warming and its Global Impacts

The SFB/TRR 172 "(AC)³" has been awarded a new grant and will continue its research in the third phase of DFG funding for a further four years. The focus is on improving understanding and prediction models for the rapidly increasing warming in the Arctic.

The Collaborative Research Centre “Arctic Amplification: Climate Relevant Atmospheric and Surface Processes and Feedback Mechanism (AC)³,” which is headed by Leipzig University, is to enter its third funding phase. This was announced today (November 24, 2023) by the German Research Foundation (DFG). From January 2024, the research network, which also includes the Universities of Bremen and Cologne, the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI), and the Leibniz Institute for Tropospheric Research (TROPOS), will continue its ground-breaking work for another four years. The overall aim is to make fundamental and significant advances in our understanding of Arctic amplification and improve the reliability of models used to predict the dramatic warming of the Arctic.

“Over the past 25 years, we have observed a drastic increase in near-surface air temperatures in the Arctic, which is two to three times more pronounced than global warming,” says Professor Manfred Wendisch, spokesperson for the Collaborative Research Centre from the Leipzig University. This phenomenon, which the interdisciplinary network has been studying and trying to understand for eight years using various scientific methods, is known as Arctic amplification. Professor Susanne Crewell, deputy spokesperson from the University of Cologne, explains: “In recent years, we have been able to quantify seasonal differences and better understand the interaction of various feedback mechanisms that are thought to be the cause of Arctic amplification.” Dr Gunnar Spreen, deputy spokesperson from the University of Bremen, adds: “This is connected to a dramatic decrease in sea ice. In summer, we only have about half of the ice that we had 40 to 50 years ago. (AC)³ is investigating which interactions between the atmosphere and ocean play a role here.”

What the Researchers Have Found Out So Far

The scientists have used existing and new data to identify short-term changes and indications in Arctic climate variables. “The Arctic atmosphere has become significantly wetter. Storm activity has also increased regionally,” summarises Manfred Wendisch. In addition, winter warming has intensified in the regions around Svalbard and the North Pole, which has led to a decrease in the thickness of sea ice in the Fram Strait and snow depth on the ice.

The research aircraft HALO and the polar aircraft Polar 5 and 6 in conjunction with the icebreaker Polarstern have been used on expeditions to the Arctic. The latter were part of the MOSAiC expedition led by the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI). The Collaborative Research Centre (AC)³ was the main German university contribution to MOSAiC.

Future Priorities and Projects

The Collaborative Research Centre / Transregio 172 “Arctic Amplification (AC)³” will answer three central questions in its third phase:

  • What are the main causes and to what extent do these contribute to Artic amplification?
  • How do changes in the transport of air masses impact the weather and climate in the Arctic and mid-latitudes?
  • What trends can be identified that are caused by Arctic amplification and how will they develop in a future, warmer climate?

To better connect their results in the future, the researchers are developing cross-cutting themes to answer key questions in four key areas: the vertical temperature gradient, surface processes, Arctic mixed-phase clouds, and transport and transformation of air masses.

The main objective of the third phase of the Collaborative Research Centre (AC)³ is to bring together the numerous observational and modelling results from the previous phases in order to make fundamental and significant advances in our understanding of Arctic amplification. In the coming years, the interdisciplinary network’s research questions will continue to provide the basis for ground-breaking insights into Arctic climate change. These will also contribute to addressing the challenges of climate change on a global scale.

Areas of Focus at the University of Bremen

The main focus of (AC)³ at the University of Bremen is on remote sensing and oceanography. In the Faculty of Physics / Electrical Engineering, research in ten sub-projects is dedicated to the analysis of clouds, water vapor, and aerosols from satellite data, the observation of sea ice changes and melt ponds on the ice, as well as research into ocean currents, ocean temperature, and the effects of climate change on the Arctic. Support for doctoral students plays an important role. Through interdisciplinary research approaches and state-of-the-art technologies, the University of Bremen makes a significant contribution to expanding our understanding of the Arctic and the global climate.

In the third funding phase, the renewed approval means that additional funds of around three million euros are available for research in Bremen.

Further Information:



Dr. Gunnar Spreen
Institute of Environmental Physics
University of Bremen
Phone: +49 421 218-62158
Email: gunnar.spreenprotect me ?!uni-bremenprotect me ?!.de

The Arctic
The Arctic is warming two to three times faster than the rest of the world. This phenomenon is known as Arctic amplification. To understand this warming, the DFG-funded Transregional Collaborative Research Centre (AC)³ was established in 2016. It includes modelling and data analysis efforts as well as observational elements.