## How mathematics helps structuring climate discussions

Rupert Klein

Free University of Berlin

2018-03-22 ~ 2018-03-22

15:00-16:00

Room.1493, Science Building No. 1

##### Abstract

Mathematics in climate research is often thought to be mainly a provider of techniques for solving the continuum mechanical equations for the flows of the atmosphere and oceans, for the motion and evolution of Earth’s ice masses, and the like. Three examples will elucidate that there is a much wider range of opportunities. Climate modelers often employ reduced forms of “the continuum mechanical equations” to efficiently address their research questions of interest. The first example discusses how mathematical analysis can provide systematic guidelines for the regime of applicability of such reduced model equations. Meteorologists define “climate”, in a narrow sense, as “the statistical description in terms of the mean and variability of relevant quantities over a period of time” (World Meteorological Society, http://www.wmo.int; see the website for a broader sense definition). Now, climate researchers are most interested in changes of the climate over time, and yet there is no unique, well-defined notion of “time dependent statistics”. In fact, there are restrictive conditions which data from time series need to satisfy for classical statistical methods to be applicable. The second example describes recent developments of analysis techniques for time series with non-trivial temporal trends. Modern climate research has joined forces with economy and the social sciences to generate a scientific basis for informed political decisions in the face of global climate change. One major type of problems hampering progress of the related interdisciplinary research consists of often subtle language barriers. The third example describes how mathematical formalization of the notion of “vulnerability” has helped structuring related interdisciplinary research efforts.

Prof. Rupert Klein studied mechanical engineering at RWTH Aachen University, Germany, and did his PhD with honors in 1988 in Aachen on "Shock initiated ignitions" in the department of mechanical engineering. He went on for a Post Doc at Princeton, back to Aachen and finally became Professor at Free University Berlin (FU Berlin) in 1997. Additionally, he was head of the department of data and computation at the Potsdam Institute for Climate Impact Research. His research group at FU Berlin is working on geophysical fluid dynamics, especially multi-scale modelling and analysis for climate simulations as well as combustion problems. Prof Klein was awarded many prizes, among them the prestigious Leibniz Prize of the German Research Foundation in 2003. He is the speaker of the collaborative research center (CRC) "Scaling Cascades in Complex Systems" and has published over 180 scientific papers.