CONTRASTING EFFECTS OF CLIMATE AND CARBON DIOXIDE ON AMAZONIAN ECOSYSTEMS SINCE THE LAST GLACIAL MAXIMUM

Amazonia is the dominant carbon pool in the terrestrial carbon cycle. Yet its history over glacial-interglacial cycles continues to remain unresolved. We investigated this issue in a series of transient, continuous 21,000 year simulations with a dynamic process-based ecosystem model. Our results indicate that changes in ecosystem distribution were governed by climate whereas carbon sequestration into biomass and soils was primarily controlled by the global rise in atmospheric carbon dioxide during deglaciation. At the last glacial maximum the Amazon Basin remained predominantly covered by evergreen rain forests, although its carbon storage was only half its present value.