human-climate connection in north central iran between 6000 and 2700 bce

During the holocene, man’s challenges with climate entered a new phase. holocene climatic cycles, by creating dry events, have imposed many subsistence tensions on water-dependent communities. the semi-arid and arid region of north central iran, which has been very vulnerable to any climate change, experienced unfavorable environmental conditions during these climatic events. so far, only a handful of early holocene rural settlements have been found in the region, possibly because of the mostly arid climate of the period. in general, the first evidence of neolithic villages in north central iran dates back to the beginning of the middle holocene, after the 8.2 ka bp event. the first cultural flourishing of this region can be seen from the last quarter of the sixth millennium bce. each cultural flourishing period seems to have declined for some time with the occurrence of a dry event. the effects of climatic tensions on human societies in north central iran have been found around 6500-6000, 5700-5400, 5000-4700, 4300-4000, and 3300-2700 bce. according to data analysis, the frequency of settlements and the trend of cultural progress gradually peaked from the early sixth millennium to the mid-fourth millennium bce, but in the second half of the latter millennium, a gradual decline began which led to the bronze age collapse in ca. 2700 bce. this event probably occurred due to the drop in temperature and the increase in the frequency and severity of aridity in the transition phase to the late holocene.