Long-term, robust climate proxy records provide a baseline against which recent climate variability can be compared, and climate models evaluated, to refine their predictive skill. To identify accurately the spatial patterns of climate change an extensive proxy network is required, but this is problematic for the Southern Hemisphere given the paucity of sites.
The Southern Annular Mode (SAM), or Antarctic Oscillation, is represented by the atmospheric pressure difference between Antarctica and the Southern Hemisphere’s mid-latitudes and is the dominant mode of regional atmospheric variability. Although the long-term pattern of change in the SAM is a critical archive for understanding the natural variability of the southern westerly airflow system, few data are presently available for the study of this meteorological phenomenon, with reliable indices of the SAM being very short, only extending back to 1957.
Given the significant impact of southern hemispheric climate variability on ocean carbon cycle and CO2 air-sea fluxes, determining whether the Southern Ocean acts as a net carbon sink or source, it is clear that more research is required to improve understanding of these regional systems and their impact on past and future climatic changes. Furthermore, new regional reconstructions are important since climate changes and extremes identified from them can exhibit much larger amplitudes than those apparent in hemispheric and global reconstructions.
The island of Tierra del Fuego is directly situated in the core path of the southern westerlies and is therefore ideally suited for studies of variability in their intensity. In particular, the region’s peatland-based palaeoclimate archives are capable of recording long-term changes in the southern westerlies, given that wind intensity and prevailing westerly circulation affects precipitation and, subsequently, influences the atmospheric moisture balance that drives changes in bog surface wetness.
The scientific aim of the PATAGON project is therefore to develop a new regional network of proxy archives and create quantitative climate reconstructions for southern South America spanning the last ~2000 years using Sphagnum-dominated peat deposits. The project will encompass a full multi-proxy suite of palaeoecological and geochemical techniques including: plant macrofossil, testate amoebae, stable isotopic (δ18O, δD, δ13C) and C/N analyses. These comprehensive and high-resolution records will be supported by a robust chronology based on a number of radiometric techniques (210Pb; 137Cs; 241Am; 210C).
This collaborative, NERC-funded project involves academics and research staff from several of the UK’s leading palaeoenvironmental departments including those of the Universities of Aberdeen, Plymouth and Swansea which, alongside Southampton, brings together a number of leading experts in the discipline of late Quaternary climate and environmental change. This research programme will also provide a UK-lead on international efforts to generate high precision climate change reconstructions, and strengthen and enhance the capacity of UK researchers to derive long-term climate change data.