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Plenary talk by Dr Yama Dixit on Indian monsoon history at International Paleoceanography Conference in Sydney

16 Sep 2019

The International Conference on Paleoceanography (ICP) gathers world experts in Paleoceanography, the history of the oceans, every three years. This year, ASE/EOS Research Fellow Dr Yama Dixit was invited as a plenary speaker at the 13th ICP held in Sydney, Australia. Her speech, on the history of the Indian summer monsoon was well received and prompted a discussion on the climate mechanisms that drives abrupt climate anomalies (like two well-known drying events that occurred 4.2 kyr BP and 8.2 kyr BP). In this light, the impact of changes in the tropical ocean climate phenomena (the El- Nino Southern Oscillation and the Indian Ocean Dipole) and also the high latitude climate phenomena (North Atlantic cooling and the slowdown of AMOC), on the monsoon system was also discussed.

As a paleoclimatologist, Dr Dixit is interested in climate variability of the quaternary period (from 2.6 million years ago and up until today), with a particular focus on the Indian monsoon. She studies how the Indian monsoon has changed in the past, what drove those changes and how they affected ancient societies. The Indian summer monsoon (ISM) system is not only a critical part of the global hydrological cycle, but millions of people on the Indian subcontinent depend on it for their livelihood, as it provides 80% of annual rainfall. Dr Dixit uses carbonate shell chemistry from lake and marine sediments as a proxy to reconstruct past climate. Both intensity and cyclicity of the ISM can be traced through layers of deposited sediment and help reconstruct past climate patterns.

The study of past climates and biogeochemical changes give insight about past climate extremes, but perhaps more importantly, keys to evaluating climate change models, and to predicting future climate and its effects, both environmental and socio-economical. Some of the findings that Dr Dixit presented at the ICP are that the ISM appears to be determined by a complex interplay of high and low latitude climate anomalies, and that the Holocene history of the ISM closely follows the cultural transformations in this region highlighting the significance of natural climate variability as one of the factors affecting ancient human settlements.

 

Read more about isotope geochemistry on the Isotope Geochemitry Group web page.