Central to the concept of coupled human and natural systems (CHANS), humans and nature are organized into interacting subsystems of a cohesive whole at multiple spatial and temporal scales. Following an overview of the challenges in implementing the CHANS concept, we used widely available measures of social, economic, and ecological systems, including gross domestic product, population size, net primary productivity, and livestock and their ratios to examine CHANS dynamics on the Mongolian Plateau from 1981 to 2010. Our cross-border analysis of coupled dynamics over the past three decades demonstrated striking contrasts between Inner Mongolia (IM) and Mongolia (MG), with policies playing shifting roles in these measures. For prioritizing future research on the CHANS concept, we hypothesize that although the divergence of IM and MG for 1981–2010 was largely driven by market reforms, the importance of socioeconomic forces driving climate changes will gradually decrease in IM while remaining important in MG.