Changes in high-altitude winds over the South Pacific produce long-term effects on the Antarctic

Nov 5, 2019

New findings from the field of Earth history are improving our grasp of climate mechanisms

Satellite image with today's sediment input from rivers in Central Chile (Foto: NASA)

In the past million years, the high-altitude winds of the southern westerly wind belt, which spans nearly half the globe, didn’t behave as uniformly over the Southern Pacific as previously assumed. Instead, they varied cyclically over periods of circa 21,000 years. A new study has now confirmed close ties between the climate of the mid and high latitudes and that of the tropics in the South Pacific, which has consequences for the carbon budget of the Pacific Southern Ocean and the stability of the West Antarctic Ice Sheet. The study, led by Dr Frank Lamy from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, also involves researchers from MARUM – Center for Marine Environmental Sciences at the University of Bremen and has just been released in the Proceedings of the National Academy of Sciences of the United States of America (PNAS).

Press release Alfred Wegener Institute

Original publication:

Frank Lamy, John C.H. Chiang, Gema Martínez-Méndez, Mieke Thierens, Helge W. Arz, Joyce Bosmans, Dierk Hebbeln, Fabrice Lambert, Lester Lembke-Jene, Jan-Berend Stuut: Precession modulation of the South Pacific westerly wind belt over the past million years. PNAS 2019. DOI: 10.1073/pnas.1905847116

Schematic depiction of changes in the ocean-atmosphere system in the South Pacific in comparison, throughout the precession cycles (21,000 years) (Graphic: Helge Arz, IOW)

Changes in fluvial sediment input off the coast of northern Chile over the past 1 million years and comparison to changes in the precession of the Earth’s axis (Graphic: Helge Arz IOW, Frank Lamy AWI)