We study high-resolution climate variability through the analysis of tree-rings and other palaeoclimate archives at regional to global scales. Instrumental climate data are evaluated and used for the calibration of these archives to reconstruct climate over the past couple hundred to thousand years. We teach introductory and methodological courses on climatology with emphasis on spatial patterns and long-term changes of climate and ecological variability.
Tree-ring network used to assess the 1452 Kuwae eruption. The eruption cooled large regions of the Northern Hemisphere and was likely the strongest such event of the last millennium.
For details see here: Esper J, Büntgen U, Hartl-Meier C, Oppenheimer C, Schneider L (2017) Northern Hemisphere temperature anomalies during the 1450s period of ambiguous volcanic forcing. Bulletin of Volcanology 79,41, doi: 10.1007/s00445-017-1125-9. (Esper_2017_BullVolc.)