The focus of Stocker's research is the development of models of climate change based on, among other, the analysis of ice cores from the polar regions. He significantly contributed to creating the "hockey stick graph" that shows a growing increase of global mean temperatures in recent times. Since 1998, he contributes to the reports of the Intergovernmental Panel on Climate Change, and is co-chairman of the IPCC Working Group I (assessing scientific aspects of the climate system and climate change) from 2008 to 2015.[1]