This seminar is run by the Oxford Centre for Tropical Forests, an Oxford Martin School Centre

Summary: The Quaternary (last c. 2.6 million years) has been characterised by repeated 'cycles' of cold (glacial) and warm (interglacial) global temperature. Glacial-interglacial cycles have been linked to changes in the Earths orbital pathway which vary on three key timescales: 1) eccentricity (100,000 years), 2) obliquity (41,000 years), and 3) precession (19-21,000 years). Over the last 1 million years the eccentricity cycle has been closely linked to global temperature by evidence obtained from marine and ice core records. This pattern of climate change has also been shown to be reflected in terrestrial vegetation change at high- and mid-latitudes; however, the impact on vegetation in the tropics remains poorly understood due to a paucity of records which span multiple glacial-interglacial cycles.

New data obtained from tropical fossil pollen records and model outputs suggest that the pattern of vegetation change at low latitudes has been fundamentally different to that observed at high- and mid-latitudes. Evidence from Lake Titicaca (high Andes), Erazo/Mera (eastern Andean flank/western Amazonia) and Lake Bosumtwi (west Africa) demonstrate that tropical vegetation: 1) is impacted by high magnitude global climate change, 2) can respond in an abrupt non-linear fashion, and 3) is linked to the precessional cycle. Global climate-vegetation models which replicate a latitudinal difference in vegetation change over the last 800,000 years suggest that variation in seasonality, which can be controlled by precession, may explain the different pattern of change identified at low latitudes.

Speaker: Dr William Gosling, Palaeoenvironmental Change Research Group, Open University

The seminars will be followed by drinks

For further information please contact jane.applegarth@eci.ox.ac.uk | +44 (0)1865 285190 (Direct)