|Title||Atmospheric methane, southern European vegetation and low-mid latitude links on orbital and millennial timescales|
|Publication Type||Journal Article|
|Year of Publication||2009|
|Authors||Tzedakis, PC, Pälike, H, Roucoux, KH, de Abreu, L|
|Journal||Earth and Planetary Science Letters|
|Keywords||ITCZ, Mediterranean, methane, millennial, orbital, Pollen, vegetation|
Pollen records from marine and terrestrial sequences in southern Europe reveal a strong coherence between changes in tree populations and atmospheric methane concentrations over the last 800 thousand years. Variations in the continental hydrological balance provide a link for the observed patterns, leading to concomitant changes in southern European vegetation, and low-latitude wetland extent and methane/volatile organic compound emissions, although additional contributions to the methane budget from extratropical sources are not excluded. Here we propose that the close coupling between low- and mid-latitude hydrological changes reflects shifts in the mean latitudinal position of the Intertropical Convergence Zone, which determines the extent to which southern Europe is dominated by subtropical or mid/high-latitude influences. This provides a conceptual framework within which to view vegetation variability in southern Europe on orbital and millennial timescales.