Kimbrough, AlenaGagan, MichaelDunbar, GavinHantoro, WahyoeShen, Chuan-ChouHu, Hsun-MingCheng, HaiEdwards, LawrenceRifai, HamdiSuwargadi, Bambang W2024-10-142024-10-142662-4435https://hdl.handle.net/1885/733721479Speleothem δ18O is widely used as a proxy for rainfall amount in the tropics on glacial-interglacial to interannual scales. However, uncertainties in the interpretation of this renowned proxy pose a vexing problem in tropical paleoclimatology. Here, we present paired multi-proxy geochemical measurements for stalagmites from southwest Sulawesi, Indonesia, and confirm changes in rainfall amount across ice age terminations. Collectively, the stalagmites span two glacial-interglacial transitions from ~380,000 to 330,000 and 230,000 to 170,000 years ago. Mg/Ca in the slow-growing stalagmites is affected by water moving through the karst and prior calcite precipitation, making it a good proxy for changes in local rainfall. When paired, Mg/Ca and δ18O corroborate prominent shifts from drier glacials to wetter interglacials in the core of the Australasian monsoon domain. These shifts in rainfall occur 4,000-7,000 years later than glacial-interglacial increases in global temperature and the associated response of Sulawesi vegetation, determined by speleothem δ13C.M.K.G., W.S.H., R.L.E., H.C. and C.-C.S.; an Australian Postgraduate Award and International Postgraduate Research Scholarship to A.K.K.; Science Vanguard Research Program of the Ministry of Science and Technology (110-2123-M 002-009), the Higher Education Sprout Project of the Ministry of Education, Taiwan, ROC (110L901001), and National Taiwan University (110L8907) to C.-C.S.; U.S. National Science Foundation grants (2202913) and (1702816) to R.L.E. and H.C.; and National Natural Science Foundation of China grants to H.C. (NSFC 41731174 and NSFC 41888101).application/pdfen-AU© 2023 The authorshttp://creativecommons.org/licenses/by/4.0/202310.1038/s43247-023-00873-82024-02-18Creative Commons Attribution licence