Abstract:Earth sciences made unprecedented progress in the 20th century and will develop further at an accelerating pace in the future. This paper briefly reviews the most important achievements contributed by several generations of Earth scientists in the world during the past century. Emphasizing the great significance of the study of the Earth system as a whole and of interactions of its all parts, research opportunities in the next decades are tentatively outlined and research priorities of interdisciplinary and Earth-system aspects are proposed. Finally, some recommendations for research implementation to both scientists and policy-makers are also made.