Reconstructing Neoproterozoic palaeoclimates using a combined data/modelling approach
Published:January 01, 2007
L. E. Sohl, M. A. Chandler, 2007. "Reconstructing Neoproterozoic palaeoclimates using a combined data/modelling approach", Deep-Time Perspectives on Climate Change: Marrying the Signal from Computer Models and Biological Proxies, M. Williams, A. M. Haywood, F. J. Gregory, D. N. Schmidt
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Climate reconstructions of the Neoproterozoic Era (1000–542 Ma) face special challenges because many proxies used to constrain younger palaeoclimates are not available/applicable in Precambrian time. Given the few available proxies, deep time climate simulations are best viewed as a means to address more fundamental questions about the nature of climate change and to address disparities in data interpretation by examining phenomena from a process-related perspective. The Global Climate Model (GCM) simulations presented here were aimed at determining what combination of forcings might have permitted the initiation of low-to mid-latitude continental ice-sheets during the Sturtian glacial interval, c. 750 Ma. However, despite the formation of extensive extratropical ice cover, tropical regions in these experiments remain too warm for the initiation of large ice-sheets. The enhanced precipitation along the leading edge of icy regions suggests that the addition of topographic relief and dynamic ice flow could make ice-sheets viable into subtropical regions. However, these simulations suggest that ‘hard’ snowball Earth solutions are only likely for much earlier intervals in Earth history, and are certainly not viable in combination with large accumulations of greenhouse gases.
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Deep-Time Perspectives on Climate Change: Marrying the Signal from Computer Models and Biological Proxies
This book unites climate modelling, palaeoceanography and palaeontology to address fundamental events in the climate history of Earth over the past 600 million years. Understanding the ‘tipping points’ that have led to rapid changes in the Earth's climate is vitally important with the realization that humans modify global climate. In an effort to better understand past and future climate change, general circulation models have become the forerunners of attempts to simulate future climate. Although extraordinarily sophisticated, they remain imperfect tools that require ‘grounding’ in geological data. In this, the study of past major climate transitions like the Palaeozoic icehouse worlds and the extreme greenhouse of the Cretaceous are invaluable. Both the mechanisms that forced changes in the Earth's climate as well as the proxies that track these changes are discussed. The central message of the book is that general circulation models tested with geological data in an iterative ‘ground truth’ process provide the best estimates of the Earth's ancient climate.