The Earth System is a complex social- environmental system of interacting physical, chemical, biological and social components and processes that determine the state and evolution of the planet and the life on it (UNEP 2019a). The Earth System can be understood more easily through its many subsystems. In this report, these subsystems are organized as follows: (1) air and climate; (2) land and biodiversity; and (3) oceans and freshwater. The increasing scale and speed of changes caused by the drivers shown in Figure 1.1 present us with urgent challenges. Changes caused by activities in sectors such as transport and energy (not represented in the figure) are also damaging the environment. Nine “planetary boundaries” have been identified. These boundaries are considered to mark the “safe zone” for the planet as long as they are not crossed (Box 1.2).
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Earth Systems
Figure 1.1 Major drivers of changes to the Earth System and its main three subsystems: air and climate, land and biodiversity, and oceans and freshwater
