Population and the Earth System

Over the last two centuries, the Human System has grown from having a small impact on the Earth System to becoming dominant. Both population and per capita consumption have grown extremely fast, especially since about 1950. We argue that Earth System Models must be coupled with Human System Models through bidirectional feedbacks. In particular, population should be modeled endogenously, rather than exogenously as in most Integrated Assessment Models. The growth of the Human System threatens to overwhelm the Carrying Capacity of the Earth System, and may be leading to collapse. The Earth Sciences can, and should be, involved in the exploration of mitigation strategies including education, regulatory policies, and technological advances.

A minimal coupled Human And Nature Dynamical model (HANDY, Motesharrei et al., 2014, J. Ecological Economics) provides simple guidance on the impact of excessive depletion of nature and excessive economic inequality, and how to avoid the resulting societal collapse.