The Uvic Earth System Climate Model and the Thermohaline Circulation in Past, Present and Future Climates

Abstract

Over the last few years significant advances have been made towards understanding the mechanisms behind climate variability over the Last Glacial Cycle. This has become possible through the development of a new breed of climate models of intermediate complexity. In this review, the philosophy behind the development of these models is discussed with particular attention given to the Uvic Earth System Climate Model. Results are then surveyed from numerous studies using these intermediate complexity, as well as other, climate models aimed at piecing together puzzles buried within the paleo proxy record. Particular attention is given to the climate feedbacks involved in glacial inception 116,000 years ago, as well as modelling efforts aimed at understanding millennial timescale Dansgaard-Oeschger oscillations and their packaging into Bond Cycles in cold climates, their association with Heinrich events, and their dependence on the mean climatic state. In examining the climate over the last 135,000 years, it is apparent that variations in the formation of intermediate waters, both in the Labrador Sea and the Antarctic Circumpolar Current, have important consequences for the stability and variability of the climate system. A discussion of some future challenges for the climate and paleoclimate community is also given.