Contribution of China to the global carbon cycle since the last glacial maximum - Reconstruction from palaeovegetation maps and an empirical biosphere model

A better understanding of the long-term global carbon cycle requires improved estimates of the changes in terrestrial carbon storage (vegetation and soil) during the last glacial-interglacial transition. A set of reconstructions of palaeovegetation and palaeoclimate in China for the last glacial maximum (LGM) and the mid-Holocene (MH) allows us to use the Osnabruck biosphere model (OEM), which needs as input only 3 climatic parameters that are easily derivable from palaeodata, to reconstruct the past terrestrial carbon storage since the LGM. The change from the conditions of the LGM (colder and drier than present) to the MH (warmer and wetter than present) resulted in a gain of 116 Pg of terrestrial carbon in China mainly due to the build-up of temperate forest and tropical monsoon rain forest, and to the effects of changes in climate and CO2 levels. However, a loss of 26 Pg of terrestrial carbon (which does not include anthropogenic disturbances) occurred in China between the MH and the present due to shifts in the area covered by the main vegetation types. Results also show that glacial-interglacial changes in climate and vegetation distribution, both associated with variations in the Asian monsoon system, significantly affected terrestrial carbon storage in China which strongly contributed to the global carbon cycle.