Antarctic evidence for an abrupt northward shift of the Southern Hemisphere westerlies at 32 ka BP.

High-resolution ice core records from coastal Antarctica are particularly useful to inform our understanding of environmental changes and their drivers. Here, we present a decadally resolved record of sea-salt sodium (a proxy for open-ocean area) and non-sea salt calcium (a proxy for continental dust) from the well-dated Roosevelt Island Climate Evolution (RICE) core, focusing on the time period between 40-26 ka BP. The RICE dust record exhibits an abrupt shift towards a higher mean dust concentration at 32 ka BP.

Bipolar impact and phasing of Heinrich-type climate variability.

During the last ice age, the Laurentide Ice Sheet exhibited extreme iceberg discharge events that are recorded in North Atlantic sediments. These Heinrich events have far-reaching climate impacts, including widespread disruptions to hydrological and biogeochemical cycles. They occurred during Heinrich stadials-cold periods with strongly weakened Atlantic overturning circulation.

A new large-volume equilibration method for high-precision measurements of dissolved noble gas stable isotopes.

Rationale: Noble gases are widely used as physically based climate proxies, notably in dissolved water samples as tracers of past recharge temperature in groundwater and air-sea gas exchange processes in seawater. Recent advances in measuring large-volume samples of dissolved noble gas isotopic ratios at high precision have expanded the range of climate parameters that can be interpreted.

Methods: We build on prior methods for measuring noble gas stable isotopes at high precision with a new large-volume equilibration (LVE) method wherein sample gases are equilibrated in the sample flask between the dissolved phase and the headspace.

Use of δO in dating a Tibetan ice core record of Holocene/Late Glacial climate.

Ice cores from the northwestern Tibetan Plateau (NWTP) contain long records of regional climate variability, but refrozen meltwater and dust in these cores has hampered development of robust timescales. Here, we introduce an approach to dating the ice via the isotopic composition of atmospheric O in air bubbles (δO), along with annual layer counting and radiocarbon dating. We provide a robust chronology for water isotope records (δO and d-excess) from three ice cores from the Guliya ice cap in the NWTP.

Coupled atmosphere-ice-ocean dynamics during Heinrich Stadial 2.

Our understanding of climate dynamics during millennial-scale events is incomplete, partially due to the lack of their precise phase analyses under various boundary conditions. Here we present nine speleothem oxygen-isotope records from mid-to-low-latitude monsoon regimes with sub-centennial age precision and multi-annual resolution, spanning the Heinrich Stadial 2 (HS2) - a millennial-scale event that occurred at the Last Glacial Maximum. Our data suggests that the Greenland and Antarctic ice-core chronologies require +320- and +400-year adjustments, respectively, supported by extant volcanic evidence and radiocarbon ages.