A dataset of the mid-brunhes period at site MD05-2925, Solomon Sea: Surface-subsurface planktonic foraminifera stable C-O isotope and Mg/Ca ratios.

Here we present derived thermal-hydrological variations data during the Marine isotope stages (MISs) 10-12 using surface and subsurface dwelling planktonic foraminiferal geochemical proxies of a sedimentary core of MD05-2925 (9.3oS, 151.5oE, water depth 1661 m, core depth 1842-2430 cm), Solomon Sea. Globigerinoides ruber (s.s., white, 250-300 µm) and Pulleniatina obliquiloculata (355-425 µm) tests were hand-picked and cleaned for stable carbon and oxygen isotopes and Mg/Ca analyses. Composite benthic foraminifera tests (>250 µm, Uvigerina spp., and Bulimina spp.) are also hand-picked and cleaned for stable oxygen isotope stratigraphy. In total, 235 and 148 measurements for C-O stable isotopes and Mg/Ca ratios for planktonic foraminifera in 2-5 cm resolution for the period from 352.1 to 462.3 ka are presented in this data report, respectively. Age model is established by tuning composite benthic foraminiferal oxygen isotope to global composite benthic foraminifera oxygen isotope stack LR04. Surface and subsurface temperatures and seawater oxygen isotopes (δ18OW, without ice volume correction) were calculated.

A tale of shifting relations: East Asian summer and winter monsoon variability during the Holocene.

Understanding the dynamics between the East Asian summer (EASM) and winter monsoon (EAWM) is needed to predict their variability under future global warming scenarios. Here, we investigate the relationship between EASM and EAWM as well as the mechanisms driving their variability during the last 10,000 years by stacking marine and terrestrial (non-speleothem) proxy records from the East Asian realm. This provides a regional and proxy independent signal for both monsoonal systems. The respective signal was subsequently analysed using a linear regression model. We find that the phase relationship between EASM and EAWM is not time-constant and significantly depends on orbital configuration changes. In addition, changes in the Atlantic Meridional Overturning circulation, Arctic sea-ice coverage, El Niño-Southern Oscillation and Sun Spot numbers contributed to millennial scale changes in the EASM and EAWM during the Holocene. We also argue that the bulk signal of monsoonal activity captured by the stacked non-speleothem proxy records supports the previously argued bias of speleothem climatic archives to moisture source changes and/or seasonality.

Nonlinear climatic sensitivity to greenhouse gases over past 4 glacial/interglacial cycles.

The paleoclimatic sensitivity to atmospheric greenhouse gases (GHGs) has recently been suggested to be nonlinear, however a GHG threshold value associated with deglaciation remains uncertain. Here, we combine a new sea surface temperature record spanning the last 360,000 years from the southern Western Pacific Warm Pool with records from five previous studies in the equatorial Pacific to document the nonlinear relationship between climatic sensitivity and GHG levels over the past four glacial/interglacial cycles. The sensitivity of the responses to GHG concentrations rises dramatically by a factor of 2-4 at atmospheric CO2 levels of >220 ppm. Our results suggest that the equatorial Pacific acts as a nonlinear amplifier that allows global climate to transition from deglacial to full interglacial conditions once atmospheric CO2 levels reach threshold levels.

Obliquity pacing of the western Pacific Intertropical Convergence Zone over the past 282,000 years.

The Intertropical Convergence Zone (ITCZ) encompasses the heaviest rain belt on the Earth. Few direct long-term records, especially in the Pacific, limit our understanding of long-term natural variability for predicting future ITCZ migration. Here we present a tropical precipitation record from the Southern Hemisphere covering the past 282,000 years, inferred from a marine sedimentary sequence collected off the eastern coast of Papua New Guinea. Unlike the precession paradigm expressed in its East Asian counterpart, our record shows that the western Pacific ITCZ migration was influenced by combined precession and obliquity changes. The obliquity forcing could be primarily delivered by a cross-hemispherical thermal/pressure contrast, resulting from the asymmetric continental configuration between Asia and Australia in a coupled East Asian-Australian circulation system. Our finding suggests that the obliquity forcing may play a more important role in global hydroclimate cycles than previously thought.