Thomas Stocker (Zurich, Switzerland, 1959) graduated in physics from ETH Zurich, where he went on to receive a PhD in Natural Sciences in 1987. After holding a series of research positions at University College London, McGill University (Montreal) and Columbia University (New York), in 1993 he moved to the University of Bern, where he is now Professor of Climate and Environmental Physics in the Institute of Physics. Author of five books and more than 260 papers in scientific journals, he has maintained a decades long association with the Intergovernmental Panel on Climate Change, as a coordinating lead author, then, between 2008 and 2015, as the co-chair of its Working Group I. It was during his tenure that the report Climate Change 2013: The Physical Science Basis was approved by the governments, providing the scientific foundation for the Paris Agreement.
Thomas Stocker’s research has focused on measuring the concentrations of carbon dioxide trapped in the air bubbles enclosed in 800,000-year-old ice cores. The Swiss scientist developed a number of climate models to help interpret this data and, by this means, understand climate changes over a very long timescale spanning several ice ages. On the basis of his research, Stocker has reached three main conclusions: firstly, carbon dioxide concentrations today are 35% higher than at any time in the past 800,000 years; secondly, today’s global warming is without precedent in at least the last 2,000 years; and thirdly, polar ice cores contain evidence of instabilities in the climate system – abrupt changes – that occurred in the past and could recur in future due to the perturbations that human action is inflicting on the climate. These phenomena also indicate that the coupled system of the atmosphere and ocean has limited stability to perturbations, with the ocean being an important element in transmitting large-scale climate disruptions between the hemispheres. This relationship had already been hypothesized, but it was the analysis of Antarctic and Greenlandic ice that finally confirmed it.