Hans Joachim Schellnhuber

Hans Joachim "John" Schellnhuber, born 7 June 1950, is a German physicist.¹ He took a doctorate in theoretical physics at the University of Regensburg in 1980 and was a postdoctoral fellow at the Institute for Theoretical Physics in Santa Barbara; from solid state physics he moved into complex systems and nonlinear dynamics.^1,2 He was the founding director of the Potsdam Institute for Climate Impact Research, which he led from 1992 to 2018, and director emeritus until 2024.² Since December 2023 he has been Director General of the International Institute for Applied Systems Analysis (IIASA) in Laxenburg, Austria.² He has also been research director of the Tyndall Centre in England and an external professor at the Santa Fe Institute.^1,2

Wikipedia credits him with helping to create the analysis of tipping elements in the climate system, the "burning embers" diagrams of risk and the budget approach to emissions.¹ In 1995 he proposed the 2 °C guardrail for global warming, later adopted by Germany, the European Union and, after Copenhagen in 2009, governments worldwide.¹ He initiated the Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP), in which more than 30 research teams compare their simulations of climate impacts on water, floods and crops.¹ Since 2019 his work has turned to the built environment and regenerative architecture, and he founded Bauhaus Earth.²

He appears in the entry on PIK.