Forcings of Indo-Pacific Warm Pool Climate During the Past One Million YearsdissertationsParish, Meredith ClairecreatorRussell, JamesAdvisorClemens, StevenReaderHerbert, TimothyReaderDalton, ColleenReaderKonecky, BronwenReaderBrown University. Department of Earth, Environmental, and Planetary Sciencessponsor2024xv, 190 p.born digitalThesis (Ph. D.)--Brown University, 2024thesesThe past one million years encompasses major changes in the Earth’s glacial-interglacial cycles, with a shift from 41- to 100-kyr during the Mid-Pleistocene Transition (MPT) and increased interglacial CO2 during the Mid-Brunhes Transition (MBT). These reorganizations of Earth’s climate and carbon cycle provide natural experiments to test the impacts of CO2 on tropical rainfall and water resources. We produced long, orbitally-resolved hydroclimate and vegetation reconstructions to uncover the evolution of hydroclimate and its primary climate forcing mechanisms in the Maritime Continent (MC), a region with global importance through transport of heat to higher latitudes. We provide a strong framework for interpreting branched glycerol dialkyl glycerol tetraethers (brGDGT), leaf wax d2H and d13C records from Lake Towuti, Indonesia on orbital timescales by producing records that span the last deglaciation. We then produce 1-Myr, orbital-scale temperature, hydroclimate, and vegetation records from Lake Towuti to constrain the controls on MC climate across major reorganizations of Earth’s carbon cylce. We show that the MC experienced hydroclimatic stability during a period of stable, warm temperature prior to the MBT, followed by increasing orbital-scale instability as interglacial CO2 concentrations rose after the MBT, suggesting strong sensitivity to climate warming. We observe prominent 41-kyr cycles in rainfall, suggesting an important role for ice volume and/or greenhouse gas concentrations in controlling precipitation in the MC. Insolation has long been presumed as the dominant forcing of hydroclimate in the tropics, yet our data point to temperature and glacial-interglacial cycles as the primary forcing of MC hydroclimate.PaleoclimatologyHydroclimateorganic biomarkersAlkanesgdgtsIndo-Pacific Warm PoolMaritime ContinentEnglishRPB20241015