Earth system processes perform work to maintain motion, cycles, and metabolisms - an aspect that is not commonly considered. In this talk, I will show how thermodynamics plays a central role in the Earth system, determining how and how much work can be extracted from sunlight. Work, in turn, is a major constraint on dynamics, from atmospheric motion to the hydrological cycle and the global biosphere. I show that by maximizing work, we can describe highly complex Earth system processes in a relatively simple way. I use examples from the atmospheric circulation, hydrology, and terrestrial ecosystems to illustrate this approach and its utility for Earth system science.

Axel Kleidon


Axel Kleidon studied physics and meteorology at the University of Hamburg and Purdue University. He received his Ph.D. in meteorology from the University of Hamburg. After his PostDoc at Stanford University, he joined the faculty of the University of Maryland. Since 2006 he has led an independent research group at the Max-Planck-Institute for Biogeochemistry in Jena, Germany. In his research, he uses thermodynamics to quantify natural energy conversions within the Earth system and their limits. He applies this approach to understand atmosphere-biosphere interactions, Earth system responses to global change, and the natural limits of renewable energy.