Stefan Rahmstorf

The 2024 Alfred Wegener Medal & Honorary Membership is awarded to Stefan Rahmstorf for exceptional and groundbreaking research in climate science and oceanography.

Stefan Rahmstorf has gained worldwide recognition for his groundbreaking work on several research topics, including the stability of ocean circulation, the modelling of climate change in Earth’s history, the analysis of sea-level rise, and the mechanisms of extreme weather events. Rahmstorf’s enthusiasm for interesting concepts in theoretical physics has repeatedly led him to new insights into the climate system. In the 1990s, his work on nonlinear dynamics and bifurcation theory led him to a new understanding of the instability of Atlantic currents. Later, he demonstrated that the concept of stochastic resonance can explain properties of abrupt ice age climate changes (Dansgaard-Oeschger events). Through his research on the thermohaline ocean circulation, he played a key role in establishing the concept of ‘tipping points’ in the climate system.

Rahmstorf is a pioneer in the field of numerical modelling of palaeoclimates and in the use of palaeoclimatological data for systematic uncertainty analysis for future climate development. For instance, he initiated the first study to estimate climate sensitivity, a crucial parameter measuring the global temperature response to CO2 doubling, by combining data from the last ice age with a large set of model simulations with systematically varied parameters. This study, along with many others by Rahmstorf, has been included in the Intergovernmental Panel on Climate Change (IPCC) reports. Rahmstorf’s work has had a decisive influence on the international discussion of sea-level rise in recent years. In 2006, he developed a new approach for sea-level studies, which calculated a significantly higher future sea-level rise than the classic IPCC models of the time. Since then, experts have widely accepted such higher projections, and the IPCC revised its forecasts upward by around 60 percent in its latest report. Rahmstorf initiated a study on the effects of ocean circulation changes on regional sea level, an important physical effect that had been previously overlooked by the research community. Since 2011, Rahmstorf shifted his attention to weather extremes and has played a crucial role in international expert discussions in this field.

Due to the breadth of his research topics, Rahmstorf is a rare generalist with a comprehensive understanding of the climate system. Consequently, he is one of the most sought-after public communicators of climate science. Rahmstorf is a highly respected and accomplished scientist, with a wide range of research interests and contributions to the scientific community. Given his exceptional contributions to the field of climate science and oceanography, Rahmstorf is a highly worthy recipient of the Alfred Wegener Medal.