Figure 3
From: CO2 and fire influence tropical ecosystem stability in response to climate change
(A) Temporal variations in the climate-fire-CO2-vegetation system of tropical West Africa over the last 28,000 years BP reconstructed from Lake Bosumtwi. Atmospheric CO2 from the EPICA (triangles)42 and Taylor Dome ice cores43 (squares). Computed changes in Northern Hemisphere summer (JJA) insolation at 6.5°N44 (grey line). Reconstructed precipitation changes from the δD values of C31 n-alkanes (blue circles) from Lake Bosumtwi15. Reconstructed changes in fire from a 20-year moving average of the frequency of charcoal layers in thin sections (brown), concentrations of the cellulose combustion byproduct levoglucosan (ng/cm2/yr) orange circles) and particulate charcoal influx (particles/cm2/yr; pink diamonds). Relative proportion of C3 and C4 plants from the δ13C values of C31 n-alkanes. (B) Expanded view of the transition from dry, frequently burned, grassland dominated ecosystems to more humid, low fire and CO2 dominated forested ecosystems during the last deglaciation. The blue dashed line indicates the onset of humid conditions, the green dashed line indicates the midpoint of the abrupt deglacial vegetation shift.
