One proposed theory for the development of agriculture was climate change. There have been several large climatic transitions between the interglacial periods. Bar Yosef researched the paleoenvironmental conditions of the Levant and suggests that about 14,000BP (before present) there were more fluctuations in precipitation than changes in temperature, ultimately responsible for the expansion of the vegetational belts. This allowed for vast latitudinal migrations, good foraging patterns, increase in population growth, and an abundance of food resources. However, between 13,000 and 12,800BP known as the Younger Dryas, conditions became colder and drier, decreasing the annual precipitations and a change in the distribution of rainfall locations (29 Oct 2009). This placed much stress on the plants and animals. According to Bar Yosef, the dry climate expanded desert conditions and caused reductions in C3 plants, used for cereal, but also the reduction of megafauna which were unable to adapt to the new environment (Bar Yosef 1998: 174). This in turn created doubts about the current nomadic organization of the foraging groups. The hunting and gathering bands soon migrated towards the Mediterranean regions to join other foraging groups to live within a close proximity and seek refuge in the small fertile areas.
Childe an advocate for climate change as the effect for the development of agriculture states in his "Oasis Hypothesis" that because of the transition to dry and cold conditions, humans and animals migrated toward the river valleys for necessary water consumption. Bar Yosef states that along with "territorial restrictions, [there was] an increased motivation for intentional cultivation" (Last Hunters 70). This not only increased population size but could have also instigated sedentary life. The ideal environment that would foster the origins of agriculture would be in an area with an abundance of resources. Previously it was considered that agriculture arose in "marginal environments - areas where severe climatic change forced human populations to find new foods to eat" (Price and Gebauer 7); it is on the contrary however, that populations unable to sustain themselves would not take the risk of testing out new methods for the accumulation of food. Agriculture requires more energy expenditure and work from all inhabitants than foraging, therefore as a struggling population, this method would not have been the best option. Childe's argument takes into account the climatic and environmental pressures but it does not provide any cultural factors that might have also influenced the development of agriculture. Braidwood challenges Childe's hypothesis and suggests a more culturally driven theory for the agricultural origins.