ABSTRACT At the Intertropical Convergence Zone (ITCZ), the northern and southern Tradewinds converge, and this region is characterized by low atmospheric pressure and high precipitation. The climate in the Timor Sea is characterized by seasonal precipitation changes driven by meridional migrations of the ITCZ and the monsoonal front. The ITCZ shifts in response to changes in the thermal balance between the northern and southern hemispheres. Thus, reconstruction of paleo-precipitation in the Timor Sea is expected to reveal past changes in both regional and global climate, the latter through inference of the ITCZ position. To reconstruct paleo-precipitation in the Timor Sea, we performed extensive radiocarbon analysis on both planktonic foraminifera and total organic carbon (TOC), which is derived from terrestrial and marine sources. Increased precipitation enhances the fraction of relatively old, terrestrial carbon to the core site, which in turn increases the difference between the ages of TOC and planktonic foraminifera. Variations in radiocarbon ages reveal that during northern hemisphere cooling intervals such as Heinrich Stadial 1 and the Younger Dryas, the ITCZ was in a southern position, thus increasing precipitation in the Timor Sea. However, the Timor Sea was dryer during the Bølling–Allerød warming as the ITCZ shifted northward. At the Intertropical Convergence Zone (ITCZ), the northern and southern Tradewinds converge, and this region is characterized by low atmospheric pressure and high precipitation. The climate in the Timor Sea is characterized by seasonal precipitation changes driven by meridional migrations of the ITCZ and the monsoonal front. The ITCZ shifts in response to changes in the thermal balance between the northern and southern hemispheres. Thus, reconstruction of paleo-precipitation in the Timor Sea is expected to reveal past changes in both regional and global climate, the latter through inference of the ITCZ position. 2005) that is related to the position of the Intertropical Convergence Zone (ITCZ) because tropical convergence causes precipitation (Xie and Arkin 1997). The seasonal migration distance of the ITCZ over the Indonesian Archipelago is the largest on Earth today (van der Kaars et al. 2000). During the austral summer, the ITCZ migrates southward, resulting in high monsoonal precipitation over the Indonesian Archipelago (Hobbs 1998; Figure 1). The ITCZ returns to northerly position (10ºN to 15ºN) during the austral winter, resulting in lower precipitation driven by the dry southeast monsoon (Hobbs 1998). The southern hemisphere, especially around Antarctica, cooled (as seen through the Antarctic Cold Reversal; ACR; Lemieux- Dudon et al. 2010) during the northern hemisphere warming (B/A). The shifting thermal balance would have pushed the ITCZ northward. However, the Δ TOC-foram did not remain high during the B/A interval because of the exposure of the Sunda Shelf (at ∼14 ka) which forced a shift of the atmospheric circulation over the Indonesian Archipelago (Du et al. 2021). The low 232Th flux and residual flux in the Flores Sea (Muller et al. 2012), and the low K/Ca ratio in the western Timor Sea (Kuhnt et al. Shaded areas correspond to Heinrich Stadial 1 (18 –14.7 ka), the Bølling–Allerød warming interval (14.7–12.9 ka) and the Younger Dryas (12.9 –11.7 ka). 1964 K Nemoto et al. https://doi.org/10.1017/RDC.2024.13 Published online by Cambridge University Press (McManus et al. 2004). 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