Hydroclimatic variability in the southwestern Indian Ocean between 6000 and 3000 years ago 1 2

16 The ‘4.2 ka event’ is frequently described as a major global climate anomaly between 4.2 17 and 3.9 ka BP, which defines the beginning of the current Meghalayan age in the Holocene epoch. 18 The ‘event’ has been disproportionately reported from proxy records from Northern Hemisphere 19 but its climatic manifestation remains much less clear in Southern Hemisphere. Here, we present 20 highly resolved and chronologically well-constrained speleothem oxygen and carbon isotopes 21 records between ~6 and 3 ka BP from Rodrigues Island in the southwestern subtropical Indian 22 Ocean, located ~600 km east of Mauritius. Our records show that the ‘4.2 ka event’ did not 23 manifest as a period of major climate change at Rodrigues Island in the context of our record’s 24 length. Instead, we find evidence for a multi-centennial drought that occurred near-continuously 25 between 3.9 and 3.5 ka BP and temporally coincided with climate change throughout the 26 Southern Hemisphere. 27 28