Since World War II, the explosion in scientific knowledge naturally led many scientists and educators, to specialize in one discipline or another. Even within a scientific discipline, such as ecology, now called environmental studies, there were many specializations. Some include water ecology, habitat studies, population studies, etc. After a half century, the over-emphasis on specialization became so pronounced, that many believed that integration among various scientific disciplines must be established anew.
This integration is most pronounced in the scientific disciplines representing any part of studies of the Earth, namely Geology, hydrology, meteorology, biology and others. A new integrated Earth Science discipline, referred to as Earth System Science, was created. The push for this integration with Earth Science was promoted most actively by the National Science Foundation (NSF) and the National Aeronautic and Space Administration (NASA).
In most scientific and education quarters, it is now recognized that people can understand how the Earth works and how we interact with the Earth, if we teach the subject in a more project based manner. Earth Science teachers are encouraged to include all the systems of the Earth in their classes. If Earth Science teachers have a greater understanding of the various spheres of the living and nonliving parts of the Earth as a system, they can effectively explain and teach Earth System Science.
To encourage you to have a basic understanding of the Earth System Science as a scientific discipline, I have included an Earth System Science WebSlide.