Climate Geochemistry

Dr. Gerald H. Haug, Prof. of ETH Zürich

The department addresses climate-ocean-atmosphere processes - from 'geologic' to annual timescales. The climate system has many interacting components and thresholds. Changes in internal feedback loops such as changes in ocean-atmosphere interactions, the oceanic heat transport, the oceanic nutrient reservoir, the nutrient status of the high latitude surface ocean and its effects on atmospheric greenhouse gases amongst many others amplify modest external forcing mechanisms and ultimately alter climate on different timescales. Periods of interest include much of the Cenozoic, the past 65 million years, including the Pliocene thermal maximum some 3 million years ago, which is the youngest geologic analogue of a 400ppm CO₂ world – the same amount as today due to anthropogenic activities.

One focus is biogeochemical processes in the polar oceans and their role in regulating atmospheric CO₂ concentration between ice ages and warmer periods. To quantify the mechanisms and causes of such major changes in the environmental conditions of the Earth, we use diverse geochemical methods, including light stable isotopes of foraminifera and organic matter, biomarkers, trace metals, and high-resolution non-destructive analytical techniques such as scanning XRF. We pursue diverse archives, including sediments from the open ocean, isolated marine basins, freshwater lakes, and speleothems.