65,000 years of vegetation change in central australia and the australian summer monsoon

Carbon isotopes in fossil emu (Dromaius novaehollandiae) eggshell from Lake Eyre, South Australia, demonstrate that the relative abundance of C4 grasses varied substantially during the past 65,000 years. Currently, C4 grasses are more abundant in regions that are increasingly affected by warm-season precipitation. Thus, an expansion of C4 grasses likely reflects an increase in the relative effectiveness of the Australian summer monsoon, which controls summer precipitation over Lake Eyre. The data imply that the Australian monsoon was most effective between 45,000 and 65,000 years ago, least effective during the Last Glacial Maximum, and moderately effective during the Holocene.

Temperature and surface-ocean water balance of the mid-holocene tropical western pacific

Skeletal Sr/Ca and 18O/16O ratios in corals from the Great Barrier Reef, Australia, indicate that the tropical ocean surface approximately 5350 years ago was 1 degrees C warmer and enriched in 18O by 0.5 per mil relative to modern seawater. The results suggest that the temperature increase enhanced the evaporative enrichment of 18O in seawater. Transport of part of the additional atmospheric water vapor to extratropical latitudes may have sustained the 18O/16O anomaly. The reduced glacial-Holocene shift in seawater 18O/16O ratio produced by the mid-Holocene 18O enrichment may help to reconcile the different temperature histories for the last deglaciation given by coral Sr/Ca thermometry and foraminiferal oxygen-isotope records.