The cause of atmospheric CO 2 change during the recent ice ages remains a first order question in climate science. Most mechanisms have invoked carbon exchange with the deep ocean, due to its large size and relatively rapid exchange time with the atmosphere 1 . The Southern Ocean is thought to play a key role in this exchange, as much of the deep ocean is ventilated to the atmosphere in this region 2 . However reconstructing changes in deep Southern Ocean carbon storage is challenging, so few direct tests of this hypothesis exist. Here we present new deep-sea coral boron isotope data that track the pH -and thus CO 2 chemistry -of the deep Southern Ocean over the last 40,000 years. At sites closest to the Antarctic continental margin, and most influenced by the deep Southern waters that form the ocean's lower overturning cell, we find a close relationship between ocean pH and atmospheric CO 2 : during intervals of low CO 2 ocean pH is low, reflecting enhanced ocean carbon storage; during intervals of rising CO 2 ocean pH rises, reflecting loss of carbon from the ocean to the atmosphere. Correspondingly, at shallower sites we find rapid (millennial to centennial-scale) pH decreases during abrupt CO 2 rise, reflecting the rapid transfer of carbon from the deep to the upper

The record of volcanic forcing of climate over the past 2500 years is based primarily on sulfate concentrations in ice cores. Of particular interest are large volcanic eruptions with plumes that reached high altitudes in the stratosphere, as these afford sulfate aerosols the longest residence time in the atmosphere, and thus have the greatest impact on radiative forcing. Sulfur isotopes measured in ice cores can be used to identify these large eruptions because stratospheric sulfur is exposed to UV radiation, which imparts a time-evolving mass independent fractionation (MIF) that is preserved in the ice. However sample size requirements of traditional measurement techniques mean that the MIF signal may be obscured, leading to an inconclusive result. Here we present a new method of measuring sulfur isotopes in ice cores by multi-collector inductively

Citation for published item:fldiniD vis wF nd whermottD prnk nd fldiniD tmes F vF nd erisD lo nd guetoD wri¡ n nd pirhildD sn tF nd ro'mnnD hirk vF nd wtteyD hvid F nd w¤ ullerD olfgng nd xitD hn gonstntin nd ynt£ n¡ onD oerto nd qri¡ Ewon¡ oD gristin nd ihrdsD hvid eF @PHISA 9egionl tempertureD tmospheri irultionD nd seEie vriility within the ounger hrys ivent onstrined using speleothem from northern seriF9D irth nd plnetry siene lettersFD RIW F ppF IHIEIIHF Further information on publisher's website: httpXGGdxFdoiForgGIHFIHITGjFepslFPHISFHQFHIS Publisher's copyright statement: NOTICE: this is the author's version of a work that was accepted for publication in Earth and Planetary Science Letters. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reected in this document. Changes may have been made to this work since it was submitted for publication. A denitive version was subsequently published in Earth and Planetary Science Letters, 419, 1 June 2015, 10.1016/j.epsl.2015 Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details.