In the past 50 years, global Earth observation has formed strong technological abilities and comprehensive systems, and played a significant role in different fields. With in-depth research on land, atmosphere and oceans, a new strategic demand for Earth Observation from space is coming forth from Earth system science and global change research. In this paper, we have proposed a new series of satellites-scientific satellites for global change research, which includes the following six satellites: atmospheric carbon satellite, aerosol satellite, night-light satellite, forest biomass satellite, glacier satellite and ocean salinity satellite; and we have presented our new suggestion entitled of Establishing a Moon-based Earth observation system, which focuses on the observation of large scale geoscientific phenomena for its several unique advantages. Meanwhile, we have introduced our idea of a Earth observation for the three poles environment comparison research, which approaches to study global change with new Earth observation techniques including Moon-based platform and scientific satellites.