Terrestrial climate during the Cenozoic Era, the development and first applications of novel biomarker proxies
The terrestrial realm is a crucial-component of Earth’s climate system. Over the last century relatively small changes in land temperature had a direct influence on food security, natural disasters, and have been linked to human conflict. In order to accurately predict future changes in terrestrial temperature, it is crucial to constrain terrestrial temperatures during past periods of natural climate change. However, despite decades of research, the majority of our understanding of past temperature is based on marine records. The lack of understanding of past terrestrial temperatures is one of the largest uncertainties in predicting the impact of anthropogenic climate change and understanding the sensitivity of the terrestrial realm to manmade climate change provides a major challenge for the scientific community.
This major gap in paleoclimate research has motivated my research of the recent years. I will present results from my ongoingresearch on the development of novel terrestrial temperature proxies, based on molecular fossils (biomarkers) of archaea and bacteria in peat. I will show that the distribution of various biomarkers in peat depends on temperature, especially isoprenoid and branched glycerol dialkyl glycerol tetraethers (GDGTs). I will then apply these proxies to ancient peat and lignite (fossilized peat) deposits to provide new insights into the dynamics of terrestrial temperatures during key periods of the Cenozoic Era; the greenhouse world of the early Paleogene (~50 Myr) and the last natural change in pCO2 during last deglaciation (20-0 kyr).