Sven Erik Jørgensen (born August 29, 1934 in Copenhagen) is an ecologist and chemist. He has become professor emeritus in environmental chemistry at the University of Copenhagen. He received in 1958 a master of science in chemical engineering from the Danish Technical University, then doctor of environmental engineering (Karlsruhe University) and doctor of science in ecological modelling (Copenhagen University). He is an honourable doctor at Coimbra University, Portugal and at Dar es Salaam University, Tanzania. In 1975 he founded a journal, Ecological Modelling, and in 1978 ISEM, the International Society of Ecological Modelling. There have been several awards: the Ruder Boskovic Medal, the Prigogine Prize, the Pascal Medal, the Einstein professorship at the Chinese Academy of Sciences, the Santa Chiara Prize for multidisciplinary teaching, and in 2004, together with William Mitsch, the Stockholm Water Prize. He has published 366 papers of which 275 were in peer-reviewed international journals, and has edited or authored 76 books, of which several have been translated into other languages (Chinese, Russian, Spanish, and Portuguese). He has authored a textbook in ecological modeling “Fundamentals of Ecological Modelling”, which was published as a fourth edition together with Brian Fath in 2011. It has been translated into Chinese and Russian (third edition). Recently he authored the textbook “Introduction to Systems Ecology”. It was published in English in 2012 and in Chinese in 2013. He was editor in chief of the Encyclopedia of Ecology published in 2008, and of the Encyclopedia of Environmental Management published during December 2012. He has taught courses in ecological modelling in 32 countries. He is the editorial board member of 18 international journals in the fields of ecology and environmental management. He is currently the president of ISEM and has been elected to the European Academy of Sciences, for which he is chairman of the Section for Environmental Sciences.