Johannes Jakob Lohmann

NP Nonlinear Processes in Geosciences

The 2025 Division Outstanding Early Career Scientist Award is awarded to Johannes Jakob Lohmann for important contributions to our understanding of non-linear climate dynamics during the last glacial period.

By innovative time series analyses of ice core records, Johannes Jakob Lohmann showed that the occurrence of abrupt climate changes comprises intrinsically deterministic dynamics modulated by slowly varying external forcing, but also a concrete stochastic driver. His work bridges long-held opposing views, and brings us closer to a definite understanding of these most puzzling abrupt changes. He has in recent years made significant advances in the theoretical understanding of multi-stability and tipping points in the climate as a chaotic, heterogeneous, and non-autonomous complex system. With an emphasis on the Atlantic ocean’s circulation, he showed that a complicated form of rate-induced tipping can occur, which may lead to a loss of predictability of the future climate state. By creative use of climate models and a deep understanding of dynamical systems, he presented an unusually deep view into the complicated bifurcation structure of the climate system, including its unstable states, which are very much underexplored. The knowledge he showed can hold the key to predicting different types of tipping points.