Geoscience Reference
In-Depth Information
seven
h
e “Long Drought” of the Mid-Holocene
h ere are only a limited number of ways societies can respond
to accumulated climatic stress: movement or social collabora-
tion; muddling their way from crisis to crisis; decisive, central-
ized leadership on the part of a few individuals; or developing
innovations that increase the carrying capacity of the land. h
e
alternative to all these options is collapse.
Brian Fagan,
Floods, Famines, and Emperors
During the mid-Holocene, climate in the West shit ed toward
warmer, drier conditions. h is climatic upheaval and prolonged drought forced
many humans to leave their home terrain in search of water and food, espe-
cially in the Great Basin and what is known today as southeastern California.
h e inland areas were the hardest hit, and, in response, the archaeological
evidence suggests that populations migrated to the coast, which of ered a
cooler climate, more moisture, and plentiful food.
Along the coast, the steady rise of sea level following the last ice age slowed
at er the massive inl ow of glacial melt waters began to taper of . Coastal
habitats began to expand, and coastal ecosystems l ourished. Coastal groups
took advantage of these abundant marine resources, establishing settlements
along the Pacii c Northwest coast, around present-day San Francisco Bay,
and as far south as California's Santa Barbara Basin and Channel Islands.
Coastal conditions also became more favorable for salmon migration,
spawning, and population growth. Salmon soon became the single most
important Native American food resource along the coast, attracting still
more humans to the area.
tahoe's submerged trees
Some of the most vivid evidence of the mid-Holocene drought comes from
Lake Tahoe, the largest alpine lake in the United States. Appropriately
