Summary of Climate and Agriculture

Climate of Late Pleistocene and Early Holocene
Favorable for Wild Grains in Fertile Crescent

Fertile Crescent is the largest Mediterranean zone
Result: Diversity of species

Greatest seasonal variation of fertile Mediterranean zones
Characterized by winter rain, hot, arid summers
Result: Favors annual plant species, like grains

Wide range of altitude and topography
Result: Species diversity, staggered harvest times

Habitat favorable for big mammals
Result: Animal domestication

NOTE: Some researchers have suggested that Holocene cooling periods,
such as the Younger Dryas, with its increased aridity, may have
encouraged greater (or perfect) reliance on cultivated crops among
populations retaining hunting and gathering.

Rowan Sage’s Cool Theory on CO₂ and Agriculture

Atmospheric CO₂ levels during the Pleistocene Ice Ages precluded development
of agriculture

At transition into Holocene, CO₂ levels increased from 200 ppm to roughly 250 ppm by 12,000 BP

Increased atmospheric CO₂ drive photosynthesis rates higher, increasing plant productivity

Climate of Early to Mid-Holocene Favorable for Population Growth

China experienced increased monsoonal rains, improving agriculture yields

Holocene warming expanded habitable areas

Climate Primary Reason for Spread of Agriculture East-West

Plant species are adapted to specific features of climate
(Seasonal changes, day-length, temperature, rainfall, etc.)

Climates tend to be similar or continuous along latitudes
(Difficult for cultivated plant species to spread to populations too far north or south,
such as those in Sub-Saharan Africa)