Pollen records from dated sediments give spatially extensive coverage of data on vegetation distribution changes and therefore, can be used for proxy indicators for reconstructions of palaeovegetation and palaeoclimate. An international project on pollen-based reconstruction of global palaeovegetation (The BIOME 6000 project of IGBP) has made great progress in the synthesis and mapping of Late Quaternary palaeoecology since its inauguration in 1994 with an international cooperation of Quaternary palynologists,palaeoecologists and botanists. The project is focus on the mid-Holocene and the last glacial maximum,conventionally associated with the millennia around 6 ka BP and 18 ka BP as key periods at which to attempt to reconstruct natural changes in the Earth system. Applications of pollen data are expected to use a global synthesis. Success depends on community-wide participation for data compilation and quality assurance, and on a robust methodology for assigning palaeorecords to biomes. Thus the biomes are applied by a global consistent standard and can be used for various vegetation types in different regions. By involving
regional experts in PFT assignments, one can combine data from different floras without compromising global consistency in biome assignments and the primary data are put into community data bases. The aim of BIOME6000 is to collect pollen data for 6 ka BP and 18 ka BP and to construct global maps of biomes,using a standard objective biomization technique which assign pollen spectra to biomes via plant functional types (PFTs). Present results have generated state-of-the-art palaeovegetation maps based on the individual site data for the two palaeo-time periods in globe-scale; many sites are over some regions in previous geographical gaps. The possibility of achieving greater realism in global depends not only on biosphere modeling developments, but also on the availability of key input information of such as basic data on PFTs, and global-scale validation data sets. Major benefits will be envisaged to be obtained from a co-evolution of the synthesis and analysis of data describing vegetation changes from the past, such as benchmarks for evaluating palaeoclimate simulations, to test biogeophysical feedback hypotheses, and to help derive estimates of changes in biospheric variables that are related to the distribution of vegetation types.
Developments of BIOME 6000 products will play great roles in the future global change science, including fields of the coupled climate-biome model simulations, the functions and impacts of atmospheric trace-gas and aerosol composition on climate changes, and the mechanisms on millennial time scale.This paper is attempted to introduce the project BIOME6000 and involved international participants including Chinese Quaternary palynologiests cooperation, to describe the method used for biome reconstruction, to review the major progresses and present products, and to discuss the applications of possible developments for the near future.