Earth surface systems are controlled by a combination of global factors (laws, principles and
relationships that apply everywhere and always) and local factors which are place-and time-
contingent. Formal arguments, framed in the context of the state factor model of soils and
ecosystems, show that where the scales of the global and local components are sufficiently
different, global or local dynamics can be discovered without considering the other.
However, the same arguments show that the total, aggregated system cannot be understood …