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Abstract Late Pleistocene changes in insolation, greenhouse gas concentrations, and ice sheets have different spatially and seasonally modulated climatic fingerprints. By exploring the seasonality of paleoclimate proxy data, we gain deeper insight into the drivers of climate changes. Here, we investigate changes in alkenone-based annual mean and Globigerinoides ruber Mg/Ca-based summer sea surface temperatures in the East China Sea and their linkages to climate forcing over the past 400,000 years. During interglacial-glacial cycles, there are phase differences between annual mean and seasonal (summer and winter) temperatures, which relate to seasonal insolation changes. These phase differences are most evident during interglacials. During glacial terminations, temperature changes were strongly affected by CO 2 . Early temperature minima, ~20,000 years before glacial terminations, except the last glacial period, coincide with the largest temperature differences between summer and winter, and with the timing of the lowest atmospheric CO 2 concentration. These findings imply the need to consider proxy seasonality and seasonal climate variability to estimate climate sensitivity. 

Abstract. The International Ocean Discovery Program (IODP) conducted a series of expeditions between 2013 and 2016 that were designed to address thedevelopment of monsoon climate systems in Asia and Australia. Significantprogress was made in recovering Neogene sections spanning the region fromthe Arabian Sea to the Sea of Japan and southward to western Australia. Highrecovery by advanced piston corer (APC) has provided a host ofsemi-continuous sections that have been used to examine monsoonal evolution. Use of the half-length APC was successful in sampling sand-rich sediment in Indian Ocean submarine fans. The records show that humidity and seasonality developed diachronously across the region, although most regions show drying since the middle Miocene and especially since ∼ 4 Ma, likely linked to global cooling. A transition from C3 to C4 vegetation oftenaccompanied the drying but may be more linked to global cooling. WesternAustralia and possibly southern China diverge from the general trend inbecoming wetter during the late Miocene, with the Australian monsoon beingmore affected by the Indonesian Throughflow, while the Asian monsoon is tied more to the rising Himalaya in South Asia and to the Tibetan Plateau in East Asia. The monsoon shows sensitivity to orbital forcing, with many regions having a weaker summer monsoon during times of northern hemisphericGlaciation. Stronger monsoons are associated with faster continentalerosion but not weathering intensity, which either shows no trend ora decreasing strength since the middle Miocene in Asia. Marine productivityproxies and terrestrial chemical weathering, erosion, and vegetation proxiesare often seen to diverge. Future work on the almost unknown Paleogene isneeded, as well as the potential of carbonate platforms as archives ofpaleoceanographic conditions. 

Much of our understanding of Earth’s past climate comes from the measurement of oxygen and carbon isotope variations in deep-sea benthic foraminifera. Yet, long intervals in existing records lack the temporal resolution and age control needed to thoroughly categorize climate states of the Cenozoic era and to study their dynamics. Here, we present a new, highly resolved, astronomically dated, continuous composite of benthic foraminifer isotope records developed in our laboratories. Four climate states—Hothouse, Warmhouse, Coolhouse, Icehouse—are identified on the basis of their distinctive response to astronomical forcing depending on greenhouse gas concentrations and polar ice sheet volume. Statistical analysis of the nonlinear behavior encoded in our record reveals the key role that polar ice volume plays in the predictability of Cenozoic climate dynamics.