Socio-economic changes and climate change in the last two decades have caused dynamic changes in Mongolia’s pastoral systems. To study these dynamics, we applied the Dryland Development Paradigm (Reynolds et al., 2007) as a framework to analyze pastoral social-ecological systems in the Tuin and Baidrag river basins, located in Bayanhongor aimag. Global warming was identified as the most critical slow variable in these drylands. Water resources in the region have already decreased below critical threshold levels, with fewer rivers flowing and lakes drying out. Social-ecological vulnerability has increased more rapidly in the desert steppe region than in other ecological zones in the study area.