The westerly winds determine weather patterns and affect carbon-dioxide (CO2
) flux in and out of the Southern Ocean, an important sink for atmospheric CO2
. Our research reconstructs changes in the westerlies over the past 5000 yr, using a marine sediment core record collected from the subantarctic Auckland Islands. Our results indicate an intensification of the westerlies around 1600 yr ago, contemporaneous with other records from comparable latitudes across the Pacific Ocean.