Maik Renner works as PostDoc at the Max-Planck-Institute for Biogeochemistry, Jena, Germany. Trained as hydrologist he assessed the skill of hydrological forecasts of the River Rhine, jointly working at the interface between research, consulting and river board authorities. During his doctorate at the meteorological department of TU Dresden and the Research Centre for Environment, Leipzig, Germany he showed that there are different signatures of climate and land-cover change in water and energy cycling, highlighting hot spots of change in hydrological functioning due to forest damage (Mountain catchments in Central Eastern Europe) or by intensification of agriculture (Corn belt in the US). Currently, he is working with Axel Kleidon on the thermodynamic limits of energy conversion processes at the earth surface interacting with the lower atmosphere. Recent publications show how these limits contribute to our understanding of water and energy cycling and thus enable the prediction of the hydro-climatic impacts of global change from first principles.