The Marpole phase of the Gulf of Georgia, SW British Columbia (2400–1200 cal B.P.) is recognized by many archaeologists as a significant period of culture change. Concurrent with this cultural phase is a climatic regime characterized by a substantial increase in forest fires associated with persistent summer drought: the Fraser Valley Fire Period (FVFP). Culturally, the Marpole phase is characterized by the widespread appearance of large houses, standardized art forms, and elaborate burials. Interactions among people of this region intensified and were, as today, economically, socially, and ideologically linked to the lower Fraser River system. Ecologically, the FVFP likely resulted in a regional decline in salmon abundance and/or predictability, especially in small streams and offshore areas, but also more berries and wildlife, and easier overland access via trail networks. The ecological diversity of the lower Fraser region, both terrestrial and riverine, resulted in both more abundant and more predictable resources than surrounding areas during this period of changing climate. We hypothesize that social and economic networks throughout the Gulf of Georgia were solidified during the Marpole phase to ensure access to Fraser resources and allow social buffering of resource uncertainty. We suggest that the differential availability of resources also allowed and encouraged individuals who had access to Fraser Valley resources to gain relatively greater prestige.