Reconstructing the Indian Monsoon response to global climate change

The Indian Summer Monsoon, a subsystem of the Asian Monsoon, is one of Earth's most dynamic expressions of oceanic atmospheric-terrestrial processes affecting some of Earth's most densely populated regions. Therefore, it is imperative to have a comprehensive understanding of the Indian Summer Monsoon in order to understand how its behaviour may be manifested by anthropogenic induced climate changes. Reconstructing how the monsoon behaved in the past presents an opportunity to disentangle its sensitivities to a range of forcing parameters (e.g. ice volume) during periods of different climatic states. However, understanding of how the Indian Summer Monsoon behaved in the past has been limited both spatially and temporally, further constrained by discrepancies among climate proxy records. This thesis fills both a temporal and spatial gap in our knowledge of the past behaviour of the Indian Summer Monsoon. High-resolution (millennial scale) records of Indian Summer Monsoon induced river runoff and surface freshening from the core convective region of the Indian Summer Monsoon, the northern Bay of Bengal and Andaman Sea, have been generated from 140 to 70 thousand years ago. These records provide an insight into how the Indian Summer Monsoon responded to the penultimate deglaciation (Termination II), the subsequent warmth of the Last Interglacial Period and ensuing oscillations between warm interstadial and cold stadial periods of Marine Isotope Stage 5. These records are compared with both high-latitude and low-latitude climate records in order to understand how the monsoon responded to changes in Earth's internal climate system and the influence of external forcing.