Late Holocene glacier change on Kerguelen Islands tracks shifts of the Southern Westerly Winds

The Southern Westerly Winds (SWW) play a vital role in regulating Earth`s climate system by driving global ocean circulation and storing vast quantities of CO₂. The strength and position of this powerful circulation pattern rapidly shifts in the face of ongoing warming. Observational time series link these developments to dramatic changes in regional temperature, precipitation and sea-ice extent. By providing a long-term context, records of past atmospheric change may provide critical baseline information to understand the causes and consequences of change. However, such reconstructions remain few and far in between due to the scarcity and remoteness of land masses in the surrounding Southern Ocean.

To address this knowledge gap we target a continuous lake sediment record from the Kerguelen Archipelago. Sitting astride the core belt of the SWW in the under-investigated Indian Ocean sector of the Southern Ocean, these islands are well-positioned to record past atmospheric circulation change. Here, we investigate the potential of utilizing changes in input of suspended glacigenic sediments to glacier-fed Lake Guynemer as barometer of regional atmospheric change. This approach capitalizes on the strong link between mass balance and erosion rates, as well as the high climatic sensitivity of small alpine glaciers. To track past variations in glacier activity, we characterize the distinct sedimentological character of these deposits using XRF core-scanning, advanced granulometry as well as environmental magnetic parameters. Our findings indicate that Late Holocene (3.5-1 ka BP) glacier change on the Kerguelen Islands tracked shifts in the SWW storm track.