When geographers study how natural processes are changing the earth, what element of geography are they using to interpret the world?

The third geographical element Physical System

Spatial, temporal and physical ad human systems.

Explanation:

A geographer studies the earth in terms of the geophysical changes and tries to answers the question based on the spatial terms as space, place and time frameworks.  The human system and the physical system and the environment at large are directly influenced by the process of the man and his technology and thus their geographic perspective is based on these six elements that bring the changes to the earth's natural processes and help in studying the future effects on the planet. Word spatial describes how the areas or spaces that are arranged by the people and forms the characteristics of their mental maps. The places and the region are cultural bound and related to the experiences of the people. The physical systems that relate to the natural ecological system and the human system refer to the socio-cultural aspects of the environment and thus these are formed by a network of patterns etc.