Atmospheric methane, southern European vegetation and low-mid latitude links on orbital and millennial timescales

Download

	PDF Restricted to Registered users only Download (1029Kb) | Request a copy
	PDF - Publishers print Restricted to Registered users only Download (2239Kb) | Request a copy

Description/Abstract

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.