“Coupled human and natural systems (CHANS) are systems in which human and natural components interact.”
Note: these systems are usually exhibiting non-linear dynamics with thresholds, reciprocal feedback loops, time lags, resilience, heterogeneity, and surprises.
Liu, J., Dietz, T., Carpenter, S.R., et al. 2007. Coupled Human and Natural Systems. Ambio, 36(8). https://doi.org/10.1126/science.1144004