The ice age ended in fits, with four reversals along the way

Glaciers began retreating around the eighteenth millennium BCE and the relief did not hold. Cold returned with the Oldest Dryas at or a little before 16,000 BCE and stayed for three thousand years. Warmth came back between about 12,700 and 10,900 BCE across two intervals that geologists call the Bolling and the Allerod, separated by a short cold snap, the Older Dryas, running roughly from 12,100 to 11,900 BCE. Then ice age conditions returned once more with the Younger Dryas at about 10,900 BCE, and only when that ended around 9700 BCE did the Holocene begin. Read as a list it looks like bookkeeping. Lived through, each reversal opened or closed whole regions to human settlement inside a few generations. Populations moved, split, merged and worked out new ways to eat. Farming, herding and the larger settled communities that followed took shape inside this instability rather than after it.

Around the middle of the fourteenth millennium BCE the Mushabian culture became established in Sinai and the Negev, carrying tools and toolmaking techniques characteristic of the late Afian of Egypt and the cultures that followed it there. The archaeologist Ofer Bar-Yosef argued that the Mushabian merged with the Geometric Kebaran, a local Levantine tradition, and that the merger produced the Natufian around 13,000 BCE. The Natufian lasted until the middle of the tenth millennium BCE, when farming began in the Middle East, and its makers are generally taken to be the cultural forebears of the early Semitic speakers. Follow that chain backwards. Grain harvesting in the Ethiopian highlands before 16,000 BCE, the Afian in Egypt by 15,000 BCE, the Mushabian in Sinai, the Natufian in the Levant, then the first farming villages of the Middle East. Every step runs south to north. The culture textbooks treat as the source of the Neolithic has an African grandparent.