Tales from the ancient Indian monsoon

The Indian (or South Asian) Monsoon is one of the most powerful meteorological phenomena on the planet, responsible for providing drinking and irrigation water to over a billion people. But its future stability under anthropogenic climate change is uncertain, with different computer models giving different answers to the question “what will happen to the monsoon in a warmer world?”. One way we can try to better understand the Indian monsoon is to interrogate the geological record for clues as to its past stability. In this talk I will show you how ancient mud from the bottom of the sea, combined with geochemistry and microfossils, can shed light on past monsoon behaviour. How did the monsoon respond to the large-scale growth of the Northern Hemisphere ice sheets 2.7 million years ago? How strong was the monsoon the last time we had ~400 ppm of CO2 in our atmosphere?