对地球系统科学的几点认识

地球系统科学将是２１世纪地球科学的主旋律，它被定义为：“将地球作为一个整体来伯全部知识；对地球的气圈、水圈、生物圈和岩石中的各种作用及各层圈间相互作用时间进行的研究”。此种学术思想可追溯到１００多年前，见於文字也有近二十年。它对当代地学的发展起了重要的推动作用，有四个特点：地球现象的远距离相互联系、影响；内动力和外动力研究一体化；地质作用和生物作用研究一体化；一类活动作为地球系统的一部分。当前地球系统科学的发展也提出了一些新问题，主要的是：在学术思路上对与岩石圈有关的地质作用有所忽视；观察研究系统不全面；还未深人到资源形成和小环境的研究中。近年来的观测试验表明，发生在岩石圈的各种地质作用正积极参与垒球各圈层间的物质能量交换。对它们的忽视，可能正是目前一些生物地球化学循环模型无法平衡的原因。

REMARKS ON EARTH SYSTEM SCIENCE

Defined as “that branch of knowledge or study dealing with Earth as a whole; study of the sum of processes operating in the atmosphere, hydrosphere, biosphere and lithosphere and the interactions between these compartments”, Earth System Science is considered as principal melody of geosciences at the 21st century. The naive academic thinkings of Earth System Science could be traced hack to 100 years ago, when Thomas C. Chamberlin (1898) put forward a hypothesis that alternate functioning of internal agencies (crustal movement, volcanism which emit (into atmosphere) and external agencies (weathering, photosynthesis, formation of organic matters, and the deposition of fossil fuels and carbonate rocks which withdraw CO2 from the atmosphere) has brought about warm and cold periods in the Earth’s history. He considered this mechanism responsible for the advancement and retreat of Permian and Quaternary glaciations. The term of Earth System Science first appeared as the name of a special NASA committee in 1983, and then a guideline book for global change study and monitoring Earth’s processes in 1988. The implementation of the ideas and methodologies of Earth System Science has played an important role in the development of modern geosciences. It reveals the mechanism of a series of earth processes by linking together the phenomena that used to be considered as irrelevant. It has improved traditional models, and provied new possibilities in prediction of various resources and environmental problems. It has not only contributed to the great achievements of Global Change (IGBP)study, but also penetrated into all fields of geosciences and changed their traditional approaches of research. The Earth System Science is characterized as: (1)linking and revealing mutual effects of the Earth’s phenomena that happened far away to each other; (2)merging the internal agencies and external agencies into an integral whole; (3)merging the geological and biogenic processes into an organic whole; (4)regarding the human activities as a part of Earth’s system. New development of Earth System Science has also faced some problems: (1) an overlook on geological processes. In the biogeochemical system, geological processes are always regarded as long term cycles comparing with the biologica1, atmospheric, and hydrological processes. Consequently, geological processes are not sufficiently addressed in different global change models, or given a parameter 1-2 order of magnitude lower than other processors; (2) incomplete in the monitoring system. For example, in the 10 core projects of IGBP, the monitoring of geological processes is completely ignored; (3) the Earth System Science approaches have not penetrated into the fields of microenvironment and studies of resources formation. The recent field experiment and monitoring on some typical sites have demonstrated that geological processes are not necessarily all long-term cycling. Some of them are actively involved in modern global biogeochemical cycles. A better estimation of the geo logical processes could be a way to solve the problem of inbalance in the available global change models.