Abstract

There is a general consensus that changes in atmospheric CO2 are a major driver of global temperature and climate change. Many studies also agree that changes in atmospheric CO2 and temperature over geological time are also linked. However, some estimates of past temperatures, derived from the isotopic analyses of marine calcitic fossils and sedimentological evidence for glacial episodes have been shown to have a limited correlation with the estimates of past atmospheric CO2 . This apparent mismatch is particularly striking in the Mesozoic. The data point to rising CO2 levels but falling temperatures. Hence this apparent negative relationship between temperature and CO2 has been used as a central argument of those questioning the role of greenhouse gases and global warming. Utilising sedimentology, geochemistry and faunal analyses together with isotopic data from a number of high latitude Arctic locations in western Siberia (the Yatria River and Taimyr Peninsula) and Svalbard (Festningen and Janusfjellet) this presentation explores the evidence for glacial episodes within the Mesozoic. This research also examines the isotopic composition of belemnites and brachiopods in order to further constrain temperature through the Mesozoic. Our new data, combined with the few published studies provide a crucial test of the current Mesozoic data and provide critical input into the debate on the main drivers of climate change.