The Milankovitch-Dansgaard-Oeschger Nexus: An Integrated Ice Core-Speleothem Synthesis of Glacial Abrupt Climate Change

Abstract

Understanding past abrupt climate change events is crucial for projecting future climate variability. This paper presents an integrated synthesis of ice core and speleothem records to investigate the Milankovitch-Dansgaard-Oeschger (DO) nexus during glacial periods. Milankovitch cycles, operating on orbital timescales, are known pacemakers of long-term glacial-interglacial transitions, while DO events represent centennial-to-millennial scale abrupt warming spells primarily identified in Greenland ice cores. By combining the strengths of high-resolution atmospheric and temperature proxies from ice cores with precisely U-Th dated, regionally distributed terrestrial hydroclimate and vegetation signals from speleothems, this study aims to reveal the spatial coherence, teleconnections, and potential orbital modulation of DO events. The synthesis critically examines the timing, magnitude, and geographical expression of these events, providing a more comprehensive understanding of their underlying mechanisms, their connection to global ice sheet dynamics and ocean circulation, and how longer-term astronomical forcing might influence their frequency and amplitude. This integrated approach offers novel insights into the complex interactions driving glacial abrupt climate change and underscores the interconnectedness of Earth's climate system components.