Southern Hemisphere Westerly Winds Drove Deglacial Mid-Latitude Peat Growth Seminar

Abstract: 
Peatlands preserve climate and environmental change over thousands of years, and arguably nowhere is this more important than the Southern Ocean region. This region has particular significance for understanding the evolution of the southern westerly winds, and their influence on ocean carbon flux, Antarctic sea ice, and regional temperature and precipitation patterns. Here we investigate the timing and drivers of widespread peatland initiation in the southern mid-latitudes after the Last Glacial Maximum, by sampling and radiocarbon-dating basal peats from sub-Antarctic islands of the South Atlantic, and collating published basal peat radiocarbon ages from peat forming regions >35°S. Using Kernel density estimate models we investigate spatial and temporal phases of peat initiation and compare with climate proxy records to identify drivers. We propose that phases of peat formation identified across different latitudinal belts are driven by a combination of warming temperatures and shifts in the latitudinal position and strength of the southern westerly winds. Changes in these winds directly drive effective precipitation and nutrient-rich dust deposition in the mid-latitudes, stimulating peat growth. Recent warming and a southward shift of the SWW since the mid-20th century hold significant implications for quantifying carbon fluxes from the Southern Ocean, with contemporary poleward-shifting winds likely to enhance net carbon losses.

Speaker Information

Dr Zoë Thomas

Zoë moved to the University of Southampton in January this year from the University of New South Wales in Sydney, Australia, where she held a Research Fellowship. Zoë’s research interests are in past climate and environmental change. Her current work on tipping points focuses on understanding feedbacks, timing, teleconnections, and impacts of abrupt changes in the Earth System.

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