Causes and purposes of human migration activities

Natural changes of climate (temperature, water source), war and food.

What drives people to migrate? In this regard, there is a popular "push-pull theory" that there are two fundamental reasons for people's migration: thrust and tension. The negative factors of the emigration place play a driving role, pushing the emigrants away from their original residence. These negative factors mainly include: 1) the exhaustion of natural resources, 2) the increase of agricultural production costs, 3) the surplus of rural labor force, and 4) the decline of income level. The positive factors of the migration place play a pulling role on the migrants, mainly including: 1) more employment opportunities, 2) higher income level, 3) better culture and public facilities, 4) better education conditions and so on. However, the place of emigration is not completely full of negative factors, and some factors need to be preserved, such as familiar environment and interpersonal network. Similarly, there are negative factors of exclusion in immigrant areas, such as unfamiliar environment, fierce competition and pressure of life. The choice of immigrants is often made after weighing the advantages and disadvantages of both sides.

In population migration, rural to urban migration is usually more common. As for the reasons for this migration, Lewis put forward the theory of dual development, arguing that the traditional agricultural sector and modern industrial sector coexist in developing countries. Because the resources that traditional departments rely on for production are non-renewable, and the economic benefits increase slowly, with the population growth, there will be zero-value labor; On the contrary, the scale of modern departments is constantly expanding, and the demand for labor will increase, thus providing an important channel for the transformation of labor in traditional departments. On the basis of Lewis model, Jinghan Fei and Ranis put forward the model of agricultural surplus labor force. In their view, Lewis did not see that the improvement of agricultural labor productivity and the growth of agricultural surplus products were prerequisites for the agricultural labor force to turn to the modern sector. Jinghan Fei and Ranis believe that the transformation of dual structure and the transfer of rural surplus labor force can be divided into three stages: the stage of agricultural surplus labor force and unlimited supply, the stage of food shortage and rising prices of agricultural products, and the stage of agricultural industrialization.