Earth system science: <italic>quo vadis</italic>?—Odyssey of the Earth I

<p indent="0mm">The tracking for the environmental effects of greenhouse gas emissions has introduced contemporary systems thinking to the Earth, leading to the birth of the Earth system science. After over four decades, two distinct directions of its future development have emerged with different foci and spatiotemporal scopes. The first direction is represented by the U.S. National Academy of Sciences 2022 report ―Next Generation of Earth System Science‖, which advocates a human dimension centered approach focusing on interactions among natural and social processes. By contrast, the second direction, which is predominant in China, emphasizes exploring the natural processes to decipher the spatiotemporal evolution of the Earth system itself, with the anthropogenic processes as just one component of the research. This endeavor has been manifested in the biannual conference series on Earth system science in Shanghai since 2010. This second direction, in effect, represents an ―upgraded version‖ of the Earth system science research. It proposes to embrace the latest advances in astronomy and space science, in Earth’s deep interior and in molecular and micro-biology. This will immensely broaden the scope of the Earth sciences through supersized cross-disciplinary collaboration, ultimately leading to a full understanding of the Earth system, a goal that inevitably requires endeavor of several decades. A four-part paper series of ―Odyssey of the Earth‖ is conceived to offer a systematic elucidation of the proposed ―upgraded Earth System Science― and to outline the framework and major research topics of the new initiation. The present paper serves an introduction and will be followed by in-depth analysis and more detailed discussions on the progresses in astronomy, deep Earth and bio/geosphere interactions and their roles in the evolution of the Earth system.