Work

Westerly wind shifts drove Southern Hemisphere mid-latitude peat growth since the last glacial

Year: 2025

Type: article

Abstract: Extratropical peatlands in the Southern Hemisphere preserve detailed information on climatic and environmental change going back millennia. They are particularly valuable for understanding the evolution of the mid-latitude southern westerly winds (SWW), which play a major role in driving regional temperature and precipitation patterns, Antarctic sea-ice extent and ocean carbon fluxes. Here we investigate the timing and drivers of peatland initiation across the southern mid-latitudes after the Last Glacial Maximum (21,000 years ago) and test how this might relate to past changes in the SWW. We radiocarbon-date basal peats from the Falkland Islands and collate published basal peat radiocarbon ages from peat-forming regions south of 35° S. Using kernel density estimate models, we find distinct latitudinal phases of post-glacial peat initiation that suggest that peat growth is sensitive to variations in SWW position through their influence on moisture availability, temperature and dust deposition. A peak in peat growth in regions north of 52.5° S during the Antarctic Cold Reversal (14,700–12,800 years ago) suggests an equatorward migration of the SWW, coinciding with a slowdown in atmospheric CO 2 increases. In light of recent SWW intensification and poleward migration, our findings highlight the potential for ongoing changes in the Southern Hemisphere climate and carbon fluxes under continued anthropogenic heating.

Source: Nature Geoscience

DOI: 10.1038/s41561-025-01842-w