The Fertile Crescent was favorable for early settlements primarily because of access to water and more fertile soil. The area includes major rivers such as the Euphrates and Tigris, which provided a reliable source of water for irrigation, agriculture, and drinking. The soil in this region was also enriched by the flooding of these rivers, making it highly fertile and conducive to farming.
While a warmer climate might have been beneficial for agriculture, it is the combination of access to water and fertile land that played a crucial role in the establishment of early settlements. The presence of mountains may have offered some protection, but they are not the primary reason for settlement in this region.