Abstract: Based on the calibrated and validated CENTURY model,aboveground net primary production (ANPP) in alpine meadow (AM, Haibei alpine meadow ecosystem research station of CAS in Qinghai province), temperate meadow steppe(TM,Yaojingzi grassland reserves in Jilin province),temperate steppe(TS,Inner Mongolia grassland ecosystem research station of CAS)and temperate desert(TD,Alashanzuo banner in Inner Mongolia autonomous region) were simulated by using observed climatic data (1961-2010) and projected climatic data (1961-2100) by PRECIS model under A2 and B2 scenarios.Therefore,the effects of climate change on ANPP in four types of grassland ecosystems were analyzed with or without considering the enhanced atmospheric CO2 concentration under A2 and B2 scenarios.The results indicated that:(1) In the past 50 years,the trend of ANPP in AM ascended significantly (P＜0.01) mainly affected by minimum temperature increase,and each ANPP in other three types of grassland ecosystems showed large inter annual variation with no significant trend.The positive correlation between ANPP and precipitation in TM,TS and TD were extremely significant (P＜0.01),while the correlation between ANPP and temperature in TM,TS and TD were relatively weaker.(2) Without considering the enhanced atmospheric CO2 effect,the average changes of ANPP in four types of grassland ecosystems in 2020s,2050s and 2080s compared to baseline (1961-1990) would increase by 4.9%, 12.0%,18.6% and 3.0%, 6.6%,8.9% under A2 and B2 scenarios,respectively.The increase rate of ANPP is TS>TD>TM>AM.(3)With considering the enhanced atmospheric CO2 effect,ANPP in four types of grassland ecosystems could increase significantly and the average changes of ANPP in 2020s,2050s and 2080s would be 20.0%,31.8%,45.6% and 9.0%,13.7%,18.0% under A2 and B2 scenarios,respectively.The increase rate of ANPP is TS>AM>TD>TM.

Key words: Climate change, Aboveground net primary production, CENTURY model, Grassland ecosystems